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Brief Guide to Doing SPICE Hands-On Lessons Using WGC

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   Brief Guide to Doing SPICE Hands-On Lessons Using WGC
      Overview
         WGC and WGC Tutorial URLs
      ``CASSINI Remote Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Time Conversion (convtm)
         Time Conversion -- Selected Extra Credit
         Obtaining Target States and Positions (getsta)
         Obtaining Target States and Positions -- Selected Extra Credit
         Spacecraft Orientation and Reference Frames (xform)
         Spacecraft Orientation and Reference Frames -- Selected Extra Credit
         Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)
         Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit
         Intersecting Vectors with an Ellipsoid and a DSK (fovint)
      ``ExoMars 2016 Remote Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Time Conversion (convtm)
         Time Conversion -- Selected Extra Credit
         Obtaining Target States and Positions (getsta)
         Obtaining Target States and Positions -- Selected Extra Credit
         Spacecraft Orientation and Reference Frames (xform)
         Spacecraft Orientation and Reference Frames -- Selected Extra Credit
         Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)
         Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit
         Intersecting Vectors with an Ellipsoid and a DSK (fovint)
      ``KPLO Remote Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Time Conversion (convtm)
         Time Conversion -- Selected Extra Credit
         Obtaining Target States and Positions (getsta)
         Obtaining Target States and Positions -- Selected Extra Credit
         Spacecraft Orientation and Reference Frames (xform)
         Spacecraft Orientation and Reference Frames -- Selected Extra Credit
         Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)
         Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit
         Intersecting Vectors with an Ellipsoid and a DSK (fovint)
      ``BepiColombo MPO Remote Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Time Conversion (convtm)
         Time Conversion -- Selected Extra Credit
         Obtaining Target States and Positions (getsta)
         Obtaining Target States and Positions -- Selected Extra Credit
         Spacecraft Orientation and Reference Frames (xform)
         Spacecraft Orientation and Reference Frames -- Selected Extra Credit
         Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)
         Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit
         Intersecting Vectors with an Ellipsoid and a DSK (fovint)
      ``CASSINI In-situ Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Step-1: ``UTC to ET''
         Step-2: ``SCLK to ET''
         Step-3: ``Spacecraft State''
         Step-4: ``Sun Direction''
         Step-5: ``Sub-Spacecraft Point''
         Step-6: ``Spacecraft Velocity''
      ``BepiColombo MPO In-situ Sensing'' Hands-On Lesson Using WGC
         Kernels Used
         Step-1: ``UTC to ET''
         Step-2: ``SCLK to ET''
         Step-3: ``Spacecraft State''
         Step-4: ``Sun Direction''
         Step-5: ``Sub-Spacecraft Point''
         Step-6: ``Spacecraft Velocity''
      ``Mars Express Geometric Event Finding'' Hands-On Lesson Using WGC
         Kernels Used
         Find View Periods
         Find Times when Target is Visible
         Extra Credit
      ``ExoMars-16 TGO Geometric Event Finding'' Hands-On Lesson Using WGC
         Kernels Used
         Find View Periods
         Find Times when Target is Visible
         Extra Credit
      ``KPLO Geometric Event Finding'' Hands-On Lesson Using WGC
         Kernels Used
         Find View Periods
         Find Times when Target is Visible
         Extra Credit
      ``BepiColombo MPO Geometric Event Finding'' Hands-On Lesson Using WGC
         Kernels Used
         Find View Periods
         Find Times when Target is Visible
         Extra Credit
      ``Binary PCK'' Hands-On Lesson Using WGC
         Moon rotation (mrotat)
         Earth rotation (erotat)




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Brief Guide to Doing SPICE Hands-On Lessons Using WGC





March 01, 2023



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Overview




This guide provides brief instructions on how to do SPICE ``Remote Sensing'' (CASSINI, ExoMars 2016, KPLO, and BepiColombo MPO), ``In-situ Sensing'' (CASSINI and BepiColombo MPO), ``Geometric Event Finding'' (Mars Express, ExoMars 2016, KPLO, and BepiColombo MPO), and ``Binary PCK'' hands-on lessons using the SPICE WebGeocalc (WGC) tool.

Instructions for each lesson are provided in a separate section below. They follow the lesson steps and individual assignments within each step, indicate which WGC computation panels (``calculations'') should be used and what inputs should be entered or selected in these calculations, and what key outputs should be expected from WGC. Where applicable, they indicate that a particular quantity computed in the lesson cannot be computed by WGC.



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WGC and WGC Tutorial URLs



WGC servers at NAIF can be accessed at:

   https://wgc.jpl.nasa.gov:8443/webgeocalc/#NewCalculation
   https://wgc2.jpl.nasa.gov:8443/webgeocalc/#NewCalculation
WGC server at ESAC can be accessed at:

   http://spice.esac.esa.int/webgeocalc/#NewCalculation
Project-specific WGC servers (e.g. for KPLO) can be accessed at the URLs provided during the class.

The WGC tutorial and examples are linked from the WGC introduction page on the NAIF server:

   https://naif.jpl.nasa.gov/naif/webgeocalc.html


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``CASSINI Remote Sensing'' Hands-On Lesson Using WGC






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Kernels Used



Use the ``SPICE Class - CASSINI Remote Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



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Time Conversion (convtm)



To compute ET seconds past J2000, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 jun 11 19:32:00
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   140254384.184620
To compute calendar ET in the default format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 jun 11 19:32:00
   Output time system        TDB
WGC will return the following calendar ET time string:

   2004-06-11 19:33:04.184625 TDB
To compute calendar ET in a custom format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 jun 11 19:32:00
   Output time system        TDB
   Custom format             YYYY-MON-DDTHR:MN:SC ::TDB
WGC will return the following calendar ET time string:

   2004-JUN-11T19:33:04
To compute spacecraft clock time, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 jun 11 19:32:00
   Output time system        Spacecraft clock (SCLK=-82)
WGC will return the following SCLK time string:

   1/1465674964.105


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Time Conversion -- Selected Extra Credit



1. To compute TDB Julian Date, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 jun 11 19:32:00
   Output time system        TDB
   Output time format        Julian Date
WGC will return the following TDB time string:

   2453168.314631800 JD TDB
5. To compute the earliest UTC time that can be converted to CASSINI spacecraft clock, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-82)
   Time format               Spacecraft clock ticks
   Input time                0.0
   Output time system        UTC
   Output time format        Calendar (year-month-day)
WGC will return the following UTC time string:

   1980-01-01 00:00:00.000000 UTC
6. To convert the spacecraft clock time obtained in the regular task back to UTC Time and present it in ISO calendar date format, with a resolution of milliseconds, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-82)
   Time format               Spacecraft clock string
   Input time                1/1465674964.105
   Output time system        UTC
   Custom format             YYYY-MM-DDTHR:MN:SC.### ::RND
WGC will return the following UTC time string:

   2004-06-11T19:31:59.999


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Obtaining Target States and Positions (getsta)



To compute the apparent state of Phoebe as seen from CASSINI in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    PHOEBE
   Observer type             Object
   Observer                  CASSINI
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -119.92092897
   2194.13933986
   -57.63897986
   -5.98023114
   -2.11880531
   -0.29482213
To compute the apparent position of Earth as seen from CASSINI in the J2000 frame and one way light time between CASSINI and the apparent position of Earth, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  CASSINI
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following position vector, km, and one way light time, s:

   353019393.12261910
   -1328180352.14030500
   -568134171.69730540
   4960.42691203
To compute the apparent position of Sun as seen from Phoebe in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  PHOEBE
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following position vector, km:

   376551465.27159620
   -1190495630.30282120
   -508438699.11000470
Note that WGC will also compute the distance between Sun and Phoebe body centers, km:

   1348176829.09957000
but it cannot convert this distance to AUs.



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Obtaining Target States and Positions -- Selected Extra Credit



5. To compute the position of the Sun as seen from Saturn in the J2000 using the following light time and aberration corrections: NONE, LT and LT+S, manually load a JUP310 Jovian satellite ephemeris SPK from the generic kernels area and specify/select the following inputs in the ``State Vector'' calculation (except for corrections):

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  SATURN
   Reference frame           J2000
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   State representation      Rectangular
and these corrections for NONE (the geometric position), LT (the reception light time only corrected position), and LT+S (the apparent position):

   Light propagation         No correction
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
WGC will return the following position vectors, km, correspondingly:

   367770592.36738380
   -1197330367.35880470
   -510369088.67673343
 
   367770572.92069393
   -1197330417.73307600
   -510369109.50883270
 
   367726456.16774523
   -1197342627.87914750
   -510372252.74684080
Unload the JUP310 Jovian satellite ephemeris SPK before proceeding to the next step.



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Spacecraft Orientation and Reference Frames (xform)



To compute the apparent state of Phoebe as seen from CASSINI in the IAU_PHOEBE body-fixed frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    PHOEBE
   Observer type             Object
   Observer                  CASSINI
   Reference frame           IAU_PHOEBE
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -1982.63976162
   -934.53047112
   -166.56259513
   3.97083213
   -3.81249566
   -2.37166299
To compute the angular separation between the apparent position of Earth and the CASSINI high gain antenna (HGA) boresight, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  EARTH
   Target shape 1            Point
   Observer 1                CASSINI
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in CASSINI_HGA frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
WGC will return the following output separation angle, deg:

   71.92414848


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Spacecraft Orientation and Reference Frames -- Selected Extra Credit



2. To compute the angular separation between the apparent position of Sun and the CASSINI HGA nominal boresight to find out if HGA is illuminated, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  SUN
   Target shape 1            Point
   Observer 1                CASSINI
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in CASSINI_HGA frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
WGC will return the following output separation angle, deg:

   73.12975129
This angle is less than 90 degrees so the HGA is illuminated.



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Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)



To compute the apparent sub-observer point of CASSINI on Phoebe modeled as an ellipsoid in the IAU_PHOEBE frame, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   104.49789074
   45.26884577
   7.38331473
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   2084.11604205
To compute the apparent sub-observer point of CASSINI on Phoebe in the IAU_PHOEBE frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   95.37257468
   40.94817689
   6.60990270
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   2094.24215979
To compute the apparent sub-solar point on Phoebe modeled as an ellipsoid as seen from CASSINI in the IAU_PHOEBE frame , specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   78.68071625
   76.87865160
   -21.88456729
To compute the apparent sub-solar point on Phoebe as seen from CASSINI in the IAU_PHOEBE frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   79.11113709
   77.33831624
   -22.02817575


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Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit



1. To compute the apparent sub-solar point on Phoebe as seen from CASSINI in the IAU_PHOEBE frame using the ``Intercept: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Intercept: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   74.54229300
   79.60686277
   -24.87078454
2. To compute the geometric sub-observer point of CASSINI on Phoebe in the IAU_PHOEBE frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   104.49708353
   45.27041148
   7.38409174
3. To compute the planetocentric coordinates of the geometric sub-observer point of CASSINI on Phoebe in the IAU_PHOEBE frame, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following latitude and longitude, deg, and radius, km:

   3.70986500
   23.42331102
   114.12088079
WGC does not allow computing planetodetic and planetographic coordinates on bodies that are tri-axial ellipsoids with different equatorial radii. Choosing the planetographic coordinates for output will result in the following error message:

   Reference frame center is not a spheroid. Planetodetic and
   planetographic coordinate representations can only be
   calculated for bodies with equal equatorial axes. The center
   body of the reference frame, PHOEBE, has equatorial axes
   that differ, 115.0 and 110.0. Use planetocentric coordinates
   instead.


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Intersecting Vectors with an Ellipsoid and a DSK (fovint)



To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Phoebe modeled as an ellipsoid in the IAU_PHOEBE frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          Ellipsoid
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vectors, km:

   91.02635667
   67.19017758
   2.03016242
 
   89.99095003
   66.72560204
   14.73282379
 
   80.96314734
   76.64306316
   14.42662102
 
   81.99683969
   77.10572511
   1.69850758
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Phoebe modeled as an ellipsoid in the IAU_PHOEBE frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          Ellipsoid
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   36.43251123
   1.02800787
 
   36.55583078
   7.49186596
 
   43.42988023
   7.37325329
 
   43.23917363
   0.86454948
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Phoebe modeled as an ellipsoid in the IAU_PHOEBE frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          Ellipsoid
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   86.39001297
   72.08919557
   8.25459687
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Phoebe modeled as an ellipsoid in the IAU_PHOEBE frame and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          Ellipsoid
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   39.84371945
   4.19587780
the following incidence, emission, and phase angles, deg:

   18.24722120
   17.85830930
   28.13948173
and the following local solar time:

   11:31:50
To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Phoebe in the IAU_PHOEBE frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          DSK model
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vectors, km:

   78.76953031
   61.56990460
   0.96393463
 
   76.58597747
   60.57892774
   13.65732587
 
   68.67722558
   71.10033236
   13.44360714
 
   73.18644320
   73.13094296
   0.93419040
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Phoebe in the IAU_PHOEBE frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          DSK model
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   38.01282665
   0.55240127
 
   38.34372978
   7.96186655
 
   45.99314861
   7.74452041
 
   44.97826691
   0.51732714
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Phoebe in the IAU_PHOEBE frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          DSK model
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   74.32619282
   66.60211698
   7.24732469
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Phoebe in the IAU_PHOEBE frame using a DSK shape model and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    PHOEBE
   Front body shape          DSK model
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Ray vector                CASSINI_ISS_NAC boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2004 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   41.86284040
   4.15340347
the following incidence, emission, and phase angles, deg:

   33.19950064
   9.22984680
   28.13948113
and the following local solar time:

   11:39:55


Top

``ExoMars 2016 Remote Sensing'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - ExoMars 2016 Remote Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Time Conversion (convtm)



To compute ET seconds past J2000, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 jun 11 19:32:00
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   582017589.184640
To compute calendar ET in the default format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 jun 11 19:32:00
   Output time system        TDB
   Output time format        Calendar (year-month-day)
WGC will return the following calendar ET time string:

   2018-06-11 19:33:09.184642
To compute calendar ET in a custom format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 jun 11 19:32:00
   Output time system        TDB
   Custom format             YYYY-MON-DDTHR:MN:SC ::TDB
WGC will return the following calendar ET time string:

   2018-JUN-11T19:33:09
To compute spacecraft clock time, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 jun 11 19:32:00
   Output time system        Spacecraft clock (SCLK=-143)
   Output time format        Spacecraft clock string
WGC will return the following SCLK time string:

   1/0070841719.26698


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Time Conversion -- Selected Extra Credit



1. To compute TDB Julian Date, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 jun 11 19:32:00
   Output time system        TDB
   Output time format        Julian Date
WGC will return the following TDB time string:

   2458281.314689600 JD TDB
5. To compute the earliest UTC time that can be converted to ExoMars-16 TGO spacecraft clock, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-143)
   Time format               Spacecraft clock ticks
   Input time                0.0
   Output time system        UTC
   Output time format        Calendar (year-month-day)
WGC will return the following UTC time string:

   2016-03-13 21:34:13.193650 UTC
6. To convert the spacecraft clock time obtained in the regular task back to UTC Time and present it in ISO calendar date format, with a resolution of milliseconds, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-143)
   Time format               Spacecraft clock string
   Input time                1/0070841719.26698
   Output time system        UTC
   Custom format             YYYY-MM-DDTHR:MN:SC.### ::RND
WGC will return the following UTC time string:

   2018-06-11T19:32:00.000


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Obtaining Target States and Positions (getsta)



To compute the apparent state of Mars as seen from TGO in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MARS
   Observer type             Object
   Observer                  EXOMARS 2016 TGO
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   2911.82242547
   -2033.80245966
   -1291.70085522
   1.30950490
   -0.05597018
   3.10432898
To compute the apparent position of Earth as seen from TGO in the J2000 frame and one way light time between TGO and the apparent position of Earth, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  EXOMARS 2016 TGO
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following position vector, km, and one way light time, s:

   -49609884.08045448
   57070665.86178913
   30304236.92973865
To compute the apparent position of Sun as seen from Mars in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MARS
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following position vector, km:

   -24712734.28893231
   194560532.94319060
   89906636.78934350
Note that WGC will also compute the distance between Sun and Mars body centers, km:

   215749214.49206870
but it cannot convert this distance to AUs.



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Obtaining Target States and Positions -- Selected Extra Credit



4. To compute the position of the Sun as seen from Mars in the J2000 using the following light time and aberration corrections: NONE, LT and LT+S, specify/select the following inputs in the ``State Vector'' calculation (except for corrections):

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MARS
   Reference frame           J2000
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   State representation      Rectangular
and these corrections for NONE (the geometric position), LT (the reception light time only corrected position), and LT+S (the apparent position):

   Light propagation         No correction
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
WGC will return the following position vectors, km, correspondingly:

   -24730875.20069792
   194558449.55971023
   89906170.85450794
 
   -24730866.48857886
   194558445.24649155
   89906168.75352160
 
   -24712734.28893231
   194560532.94319060
   89906636.78934350


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Spacecraft Orientation and Reference Frames (xform)



To compute the apparent state of Mars as seen from TGO in the IAU_MARS body-fixed frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MARS
   Observer type             Object
   Observer                  EXOMARS 2016 TGO
   Reference frame           IAU_MARS
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -2843.46412456
   2235.45954373
   1095.89496870
   0.31144328
   -1.15192925
   3.08212262
To compute the angular separation between the apparent position of Mars and the TGO nominal instrument view direction, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  MARS
   Target shape 1            Point
   Observer 1                EXOMARS 2016 TGO
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Y axis in TGO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         Yes
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
WGC will return the following output separation angle, deg:

   5.43847143


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Spacecraft Orientation and Reference Frames -- Selected Extra Credit



2. To compute the angular separation between the apparent position of Sun and the TGO nominal instrument view direction to find out if the science deck illuminated, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  SUN
   Target shape 1            Point
   Observer 1                EXOMARS 2016 TGO
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Y axis in TGO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         Yes
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
WGC will return the following output separation angle, deg:

   130.54279733
This angle is greater than 90 degrees so the science deck is not illuminated.



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Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)



To compute the apparent sub-observer point of TGO on Mars in the IAU_MARS frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   2554.16465516
   -2008.01038262
   -983.24042077
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   385.04529279
To compute the apparent sub-observer point of TGO on Mars in the IAU_MARS frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   2554.22331603
   -2008.05650034
   -983.26327153
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   384.96725758
To compute the apparent sub-solar point on Mars as seen from TGO in the IAU_MARS frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   487.58869797
   -3348.61049793
   -286.69722014
To compute the apparent sub-solar point on Mars as seen from TGO in the IAU_MARS frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   488.09583992
   -3352.09336966
   -286.99895399


Top

Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit



1. To compute the apparent sub-solar point on Mars as seen from TGO in the IAU_MARS frame using the ``Intercept: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            Intercept: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   487.54669671
   -3348.32205372
   -290.07721511
2. To compute the apparent sub-observer point of TGO on Phobos in the IAU_PHOBOS frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOBOS
   Reference frame           IAU_PHOBOS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   12.05913904
   4.17308831
   -0.67546616
3. To compute the planetocentric coordinates of the apparent sub-observer point of TGO on Phobos in the IAU_PHOBOS frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOBOS
   Reference frame           IAU_PHOBOS
   Observer                  EXOMARS 2016 TGO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following latitude and longitude, deg, and radius, km:

   -3.03000878
   19.08827715
   12.77864449
WGC does not allow computing planetodetic and planetographic coordinates on bodies that are tri-axial ellipsoids with different equatorial radii. Choosing the planetographic coordinates for output will result in the following error message:

   Reference frame center is not a spheroid. Planetodetic and
   planetographic coordinate representations can only be
   calculated for bodies with equal equatorial axes. The center
   body of the reference frame, PHOBOS, has equatorial axes
   that differ, 13.0 and 11.4. Use planetocentric coordinates
   instead.


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Intersecting Vectors with an Ellipsoid and a DSK (fovint)



To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Mars modeled as an ellipsoid in the IAU_MARS frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          Ellipsoid
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vectors, km:

   2535.00445179
   -2028.52838809
   -990.59432639
 
   2525.05593461
   -2042.07461651
   -988.19646467
 
   2525.20138167
   -2042.10358036
   -987.76992477
 
   2535.14886773
   -2028.55774855
   -990.16957287
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Mars modeled as an ellipsoid in the IAU_MARS frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          Ellipsoid
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   -38.66704048
   -16.96728341
 
   -38.96331703
   -16.92492977
 
   -38.96210076
   -16.91739679
 
   -38.66585276
   -16.95978024
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Mars modeled as an ellipsoid in the IAU_MARS frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          Ellipsoid
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   2530.12229730
   -2035.30663798
   -989.18816471
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Mars modeled as an ellipsoid in the IAU_MARS frame and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          Ellipsoid
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   -38.81424755
   -16.94244506
the following incidence, emission, and phase angles, deg:

   43.72871855
   6.08637448
   49.45727680
and the following local solar time:

   14:51:36
To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Mars in the IAU_MARS frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          DSK model
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vectors, km:

   2535.27825807
   -2028.71207603
   -990.68783903
 
   2525.35917194
   -2042.25880287
   -988.29907684
 
   2525.50638508
   -2042.28889640
   -987.87359025
 
   2535.42250373
   -2028.74138215
   -990.26344789
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Mars in the IAU_MARS frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          DSK model
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   -38.66655257
   -16.96717476
 
   -38.96247962
   -16.92485905
 
   -38.96125942
   -16.91733365
 
   -38.66536612
   -16.95967901
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Mars in the IAU_MARS frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          DSK model
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Rectangular
WGC will return the following position vector, km:

   2530.47105768
   -2035.52942714
   -989.30698550
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Mars in the IAU_MARS frame using a DSK shape model and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MARS
   Front body shape          DSK model
   Reference frame           IAU_MARS
   Observer                  EXOMARS 2016 TGO
   Ray vector                TGO_NOMAD_LNO_NAD boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2018 JUN 11 19:32:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   -38.81345348
   -16.94234008
the following incidence, emission, and phase angles, deg:

   44.38719437
   5.46181871
   49.45727689
and the following local solar time:

   14:51:36


Top

``KPLO Remote Sensing'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - KPLO Remote Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Time Conversion (convtm)



To compute ET seconds past J2000, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   662822439.183960
To compute calendar ET in the default format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Output time system        TDB
   Output time format        Calendar (year-month-day)
WGC will return the following calendar ET time string:

   2021-01-02 01:20:39.183959 TDB
To compute calendar ET in a custom format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Output time system        TDB
   Custom format             YYYY-MON-DDTHR:MN:SC ::TDB
WGC will return the following calendar ET time string:

   2021-JAN-02T01:20:39
To compute spacecraft clock time, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Output time system        Spacecraft clock (SCLK=-155)
   Output time format        Spacecraft clock string
WGC will return the following SCLK time string:

   1/1095:4530960


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Time Conversion -- Selected Extra Credit



1. To compute TDB Julian Date, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Output time system        TDB
   Output time format        Julian Date
WGC will return the following TDB time string:

   2459216.556009100 JD TDB
5. To compute the earliest UTC time that can be converted to KPLO spacecraft clock, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-155)
   Time format               Spacecraft clock ticks
   Input time                0.0
   Output time system        UTC
   Output time format        Calendar (year-month-day)
WGC will return the following UTC time string:

   2000-01-01 12:00:00.000000 UTC
6. To convert the spacecraft clock time obtained in the regular task back to UTC Time and present it in ISO calendar date format, with a resolution of milliseconds, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-155)
   Time format               Spacecraft clock string
   Input time                1/1095:4530960
   Output time system        UTC
   Custom format             YYYY-MM-DDTHR:MN:SC.### ::RND
WGC will return the following UTC time string:

   2021-01-02T01:19:30.000


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Obtaining Target States and Positions (getsta)



To compute the apparent state of Moon as seen from KPLO in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MOON
   Observer type             Object
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -1644.52619495
   403.44030666
   -659.48288212
   -0.68365295
   -0.53710111
   1.40358849
To compute the apparent position of Earth as seen from KPLO in the J2000 frame and one way light time between KPLO and the apparent position of Earth, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   State representation      Rectangular
WGC will return the following position vector, km, and one way light time, s:

   274796.47231277
   -229775.66219176
   -132406.96430545
To compute the apparent position of Sun as seen from Moon in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MOON
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   State representation      Rectangular
WGC will return the following position vector, km:

   29767887.20725118
   -132448141.93447962
   -57447546.63910401
Note that WGC will also compute the distance between Sun and Moon body centers, km:

   147407116.60408977
but it cannot convert this distance to AUs.



Top

Obtaining Target States and Positions -- Selected Extra Credit



4. To compute the position of the Sun as seen from Moon in the J2000 using the following light time and aberration corrections: NONE, LT and LT+S, specify/select the following inputs in the ``State Vector'' calculation (except for corrections):

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MOON
   Reference frame           J2000
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   State representation      Rectangular
and these corrections for NONE (the geometric position), LT (the reception light time only corrected position), and LT+S (the apparent position):

   Light propagation         No correction
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
WGC will return the following position vectors, km, correspondingly:

   29782863.55498986
   -132445301.95992541
   -57446341.26913592
 
   29782869.37259879
   -132445297.37780900
   -57446339.48277447
 
   29767887.20725118
   -132448141.93447962
   -57447546.63910401


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Spacecraft Orientation and Reference Frames (xform)



To compute the apparent state of Moon as seen from KPLO in the MOON_ME body-fixed frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MOON
   Observer type             Object
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Reference frame           MOON_ME
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -1371.82545359
   -948.54151590
   -721.46522871
   -0.54249964
   -0.35188864
   1.51918815
To compute the angular separation between the apparent position of Moon and the KPLO nominal instrument view direction, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  MOON
   Target shape 1            Point
   Observer 1                KOREA PATHFINDER LUNAR ORBITER
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in KPLO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
WGC will return the following output separation angle, deg:

   29.98967834


Top

Spacecraft Orientation and Reference Frames -- Selected Extra Credit



2. To compute the angular separation between the apparent position of Sun and the KPLO nominal instrument view direction to find out if the science deck illuminated, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  SUN
   Target shape 1            Point
   Observer 1                KOREA PATHFINDER LUNAR ORBITER
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in KPLO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
WGC will return the following output separation angle, deg:

   133.58682151
This angle is greater than 90 degrees so the science deck is not illuminated.



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Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)



To compute the apparent sub-observer point of KPLO on Moon in the MOON_ME frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1311.59999155
   906.89881368
   689.78167845
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   79.93809991
To compute the apparent sub-observer point of KPLO on Moon in the MOON_ME frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1310.56131465
   906.18062554
   689.23543792
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   81.31384578
To compute the apparent sub-solar point on Moon as seen from KPLO in the MOON_ME frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1333.60421904
   -1113.43170986
   -18.12110449
To compute the apparent sub-solar point on Moon as seen from KPLO in the MOON_ME frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1332.31355108
   -1112.35412588
   -18.10356680


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Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit



1. To compute the apparent sub-solar point on Moon as seen from KPLO in the MOON_ME frame using the ``Intercept: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Intercept: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1333.60421904
   -1113.43170986
   -18.12110449
2. To compute the geometric sub-observer point of KPLO on Mars in the IAU_MARS frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   -3128.42290664
   -249.60832325
   -1290.34782992
3. To compute the planetocentric coordinates of the apparent sub-observer point of KPLO on Mars in the IAU_MARS frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetocentric
WGC will return the following planetocentric longitude and latitude, deg, and radius, km:

   -173.59883389
   -22.35046430
   3393.27735444
To compute the planetographic coordinates of the apparent sub-observer point of KPLO on Mars in the IAU_MARS frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MARS
   Reference frame           IAU_MARS
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetographic
WGC will return the following planetographic longitude and latitude, deg, and radius, km:

   173.59883389
   -22.58938265
   3393.27735444


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Intersecting Vectors with an Ellipsoid and a DSK (fovint)



To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Moon modeled as an ellipsoid in the MOON_ME frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          Ellipsoid
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vectors, km:

   1330.39103977
   884.38754332
   682.99129900
 
   1325.50103256
   881.18320405
   696.50695157
 
   1317.31188523
   893.66760811
   696.13674177
 
   1321.96554453
   896.72462104
   683.26481915
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Moon modeled as an ellipsoid in the MOON_ME frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          Ellipsoid
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   33.61427482
   23.14822282
 
   33.61566370
   23.63385243
 
   34.15306470
   23.62052663
 
   34.15009526
   23.15803308
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Moon modeled as an ellipsoid in the MOON_ME frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          Ellipsoid
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1323.70921165
   889.16480649
   689.73808789
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Moon modeled as an ellipsoid in the MOON_ME frame and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          Ellipsoid
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   33.89013253
   23.39041849
the following incidence, emission, and phase angles, deg:

   75.36348395
   15.71930997
   90.97449383
and the following local solar time:

   16:54:59
To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of Moon in the MOON_ME frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          DSK model
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vectors, km:

   1330.03476491
   883.83684875
   682.66101343
 
   1324.62670338
   879.91370704
   696.03612460
 
   1315.94194737
   892.28962201
   695.50031146
 
   1321.20632985
   895.93628065
   682.68377376
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of Moon in the MOON_ME frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          DSK model
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   33.60489695
   23.14600512
 
   33.59501327
   23.63854822
 
   34.13968615
   23.62650516
 
   34.14197605
   23.15430060
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of Moon in the MOON_ME frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          DSK model
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Rectangular
WGC will return the following position vector, km:

   1322.78357023
   888.02386624
   689.12826986
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of Moon in the MOON_ME frame using a DSK shape model and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MOON
   Front body shape          DSK model
   Reference frame           MOON_ME
   Observer                  KOREA PATHFINDER LUNAR ORBITER
   Ray vector                KPLO_POLCAM-R boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2021 JAN 02 01:19:30
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   33.87463406
   23.39034854
the following incidence, emission, and phase angles, deg:

   79.62243678
   12.44723587
   90.97449322
and the following local solar time:

   16:54:55


Top

``BepiColombo MPO Remote Sensing'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - BepiColombo MPO Remote Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Time Conversion (convtm)



To compute ET seconds past J2000, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   852386745.184030
To compute calendar ET in the default format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        TDB
   Output time format        Calendar (year-month-day)
WGC will return the following calendar ET time string:

   2027-01-05 02:05:45.184031 TDB
To compute calendar ET in a custom format, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        TDB
   Custom format             YYYY-MON-DDTHR:MN:SC ::TDB
WGC will return the following calendar ET time string:

   2027-JAN-05T02:05:45
To compute spacecraft clock time, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        Spacecraft clock (SCLK=-121)
   Output time format        Spacecraft clock string
WGC will return the following SCLK time string:

   1/0863834674:28127


Top

Time Conversion -- Selected Extra Credit



1. To compute TDB Julian Date, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        TDB
   Output time format        Julian Date
WGC will return the following TDB time string:

   2461410.5873285187 JD TDB
5. To compute the earliest UTC time that can be converted to BepiColombo MPO spacecraft clock, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock ticks
   Input time                0.0
   Output time system        UTC
   Output time format        Calendar (year-month-day)
WGC will return the following UTC time string:

   1999-08-22 00:00:05.204000 UTC
6. To convert the spacecraft clock time obtained in the regular task back to UTC Time and present it in ISO calendar date format, with a resolution of milliseconds, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                1/0863834674:28127
   Output time system        UTC
   Custom format             YYYY-MM-DDTHR:MN:SC.### ::RND
WGC will return the following UTC time string:

   2027-01-05T02:04:36.000


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Obtaining Target States and Positions (getsta)



To compute the apparent state of MERCURY as seen from MPO in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MERCURY
   Observer type             Object
   Observer                  BEPICOLOMBO MPO
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -683.20708781
   -1438.94585601
   -2427.81935629
   0.03613279
   2.35990408
   -1.78341780
To compute the apparent position of Earth as seen from MPO in the J2000 frame and one way light time between MPO and the apparent position of Earth, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  BEPICOLOMBO MPO
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
WGC will return the following position vector, km, and one way light time, s:

   -59257854.69091041
   185201786.21846142
   88178321.17891033
 
   712.19341196
To compute the apparent position of Sun as seen from Mercury in the J2000 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MERCURY
   Reference frame           J2000
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
WGC will return the following position vector, km:

   -23429947.23907467
   54297427.57199317
   31434173.46824882
Note that WGC will also compute the distance between Sun and MERCURY body centers, km:

   66972235.51736662
but it cannot convert this distance to AUs.



Top

Obtaining Target States and Positions -- Selected Extra Credit



2. To compute the geometric position of Jupiter as seen from Mercury in the J2000 frame, manually load a JUP365 Jovian satellite ephemeris SPK from the generic kernels area and specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    JUPITER
   Observer type             Object
   Observer                  MERCURY
   Reference frame           J2000
   Light propagation         No correction
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
WGC will return the following position vector, km:

   -623644094.41838810
   532767093.11246020
   251130102.03451324
3. To compute the position of the Sun as seen from Mercury in the J2000 frame using the following light time and aberration corrections: NONE, LT and LT+S, with the JUP365 Jovian satellite ephemeris SPK still loaded, specify/select the following inputs in the ``State Vector'' calculation (except for corrections):

   Target type               Object
   Target                    SUN
   Observer type             Object
   Observer                  MERCURY
   Reference frame           J2000
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
and these corrections for NONE (the geometric position), LT (the reception light time only corrected position), and LT+S (the apparent position):

   Light propagation         No correction
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
 
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
WGC will return the following position vectors, km, correspondingly:

   -23438490.40236970
   54294213.48461554
   31433347.02463599
 
   -23438492.54961504
   54294212.27207869
   31433346.55007268
 
   -23430052.90345647
   54297381.15594409
   31434164.77541952
Unload the JUP365 Jovian satellite ephemeris SPK before proceeding to the next step.



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Spacecraft Orientation and Reference Frames (xform)



To compute the apparent state of MERCURY as seen from MPO in the IAU_MERCURY body-fixed frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MERCURY
   Observer type             Object
   Observer                  BEPICOLOMBO MPO
   Reference frame           IAU_MERCURY
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -2354.69762022
   -762.54754931
   -1518.40846958
   1.20858923
   0.39425920
   -2.67112542
To compute the angular separation between the apparent position of MERCURY and the MPO nominal instrument view direction, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  MERCURY
   Target shape 1            Point
   Observer 1                BEPICOLOMBO MPO
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in MPO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
WGC will return the following output separation angle, deg:

   0.00897766


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Spacecraft Orientation and Reference Frames -- Selected Extra Credit



2. To compute the angular separation between the apparent position of Sun and the MPO nominal instrument view direction to find out if the science deck illuminated, specify/select the following inputs in the ``Angular Separation'' calculation:

   Specification type        Two directions
   Direction type 1          Position
   Target 1                  SUN
   Target shape 1            Point
   Observer 1                BEPICOLOMBO MPO
   Light propagation 1       To observer
   Light-time algorithm 1    Newtonian
   Stellar aberration 1      Corrected for stellar aberration
   Use anti-vector 1         No
   Direction type 2          Vector
   Ray vector 2              Z axis in MPO_SPACECRAFT frame
   Correction type 2         None
   Use anti-vector 2         No
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
WGC will return the following output separation angle, deg:

   135.39275877
This angle is greater than 90 degrees so the science deck is not illuminated.



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Computing Sub-s/c and Sub-solar Points on an Ellipsoid and a DSK (subpts)



To compute the apparent sub-observer point of MPO on MERCURY in the IAU_MERCURY frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1978.72631908
   640.79260145
   1275.61063011
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   463.63403747
To compute the apparent sub-observer point of MPO on MERCURY in the IAU_MERCURY frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1979.55761722
   641.06180756
   1276.14754350
Note that WCG will compute the altitude but it will be labeled ``Observer Distance (km)'' in the output table and will have the following distance, km:

   462.60838580
To compute the apparent sub-solar point on MERCURY as seen from MPO in the IAU_MERCURY frame using the ``Near point: ellipsoid'' method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1526.83084694
   1903.93597088
   -1.43551256
To compute the apparent sub-solar point on MERCURY as seen from MPO in the IAU_MERCURY frame using a DSK shape model and the nadir point method, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            NADIR/DSK/UNPRIORITIZED
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1525.67256731
   1902.49161289
   -1.43442153


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Computing Sub-spacecraft and Sub-solar Points -- Selected Extra Credit



1. To compute the apparent sub-solar point on MERCURY as seen from MPO in the IAU_MERCURY frame using the ``Intercept: ellipsoid'' method, manually load a JUP365 Jovian satellite ephemeris SPK that will be needed for subsequent ``Extra Credit steps'' from the generic kernels area and specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Intercept: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1526.82756104
   1903.93860405
   -1.43802202
2. To compute the geometric sub-observer point of MPO on Europa in the IAU_EUROPA frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    EUROPA
   Reference frame           IAU_EUROPA
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   -753.48359857
   -1366.70324298
   -24.29565536
3. To compute the planetocentric coordinates of the apparent sub-observer point of MPO on Europa in the IAU_EUROPA frame using the 'Near point: ellipsoid' method, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    EUROPA
   Reference frame           IAU_EUROPA
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Planetocentric
WGC will return the following latitude and longitude, deg, and radius, km:

   -0.89189109
   -118.86859441
   1560.83489408
WGC does not allow computing planetodetic and planetographic coordinates on bodies that are tri-axial ellipsoids with different equatorial radii. Choosing the planetographic coordinates for output will result in the following error message:

   Reference frame center is not a spheroid. Planetodetic and
   planetographic coordinate representations can only be
   calculated for bodies with equal equatorial axes. The center
   body of the reference frame, EUROPA, has equatorial axes
   that differ, 1562.6 and 1560.3. Use planetocentric coordinates
   instead.
Unload the JUP365 Jovian satellite ephemeris SPK before proceeding to the next step.



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Intersecting Vectors with an Ellipsoid and a DSK (fovint)



To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of MERCURY modeled as an ellipsoid in the IAU_MERCURY frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          Ellipsoid
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vectors, km:

   1973.71676409
   645.43602637
   1281.00907254
 
   1979.64324274
   647.35380261
   1270.87514457
 
   1983.30742254
   636.03711992
   1270.87623002
 
   1977.38104498
   634.11904820
   1281.01014962
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of MERCURY modeled as an ellipsoid in the IAU_MERCURY frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          Ellipsoid
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   18.10854840
   31.66988939
 
   18.10801829
   31.39055578
 
   17.78079510
   31.39058566
 
   17.78033503
   31.66991913
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of MERCURY modeled as an ellipsoid in the IAU_MERCURY frame, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          Ellipsoid
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1978.52391704
   640.74031886
   1275.95016484
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of MERCURY modeled as an ellipsoid in the IAU_MERCURY frame and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          Ellipsoid
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   17.94442417
   31.53033979
the following incidence, emission, and phase angles, deg:

   44.64363856
   0.05864845
   44.60856489
and the following local solar time:

   09:46:41
To compute the Cartesian position vectors of the FOV boundary vector surface intercept points on the surface of MERCURY in the IAU_MERCURY frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          DSK model
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vectors, km:

   1974.25716440
   645.60214021
   1281.34585342
 
   1980.44938049
   647.60139206
   1271.40726839
 
   1984.03435100
   636.28474958
   1271.36080444
 
   1978.15849786
   634.38367993
   1281.49936711
To compute the planetocentric longitudes and latitudes of the FOV boundary vector surface intercept points on the surface of MERCURY in the IAU_MERCURY frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          DSK model
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA
                             field-of-view boundary vectors
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Planetocentric
WGC will return the following longitudes and latitudes, deg:

   18.10827034
   31.66965115
 
   18.10759955
   31.39090934
 
   17.78117498
   31.39090758
 
   17.78073720
   31.66957299
Both computations above also returned the illumination angles the FOV boundary vector surface intercept points but these angles were omitted from the output shown above.

To compute the Cartesian position vectors of the FOV boresight surface intercept point on the surface of MERCURY in the IAU_MERCURY frame using a DSK shape model, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          DSK model
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Rectangular
WGC will return the following position vector, km:

   1979.35742495
   641.01021051
   1276.48746436
To compute the planetocentric longitude and latitude of the FOV boresight surface intercept point on the surface of MERCURY in the IAU_MERCURY frame using a DSK shape model and the illumination angles and the local solar time on a 24-hour clock at this point, specify/select the following inputs in the ``Surface Intercept Point'' calculation:

   Target                    MERCURY
   Front body shape          DSK model
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Ray vector                MPO_SIMBIO-SYS_HRIC_FPA boresight
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   17.94442318
   31.53033533
the following incidence, emission, and phase angles, deg:

   45.34859624
   1.13773104
   44.60856527
and the following local solar time:

   09:46:41


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``CASSINI In-situ Sensing'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - CASSINI In-situ Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



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Step-1: ``UTC to ET''



To compute ET seconds past J2000 for a given UTC string, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2004-06-11T19:32:00
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   140254384.184620


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Step-2: ``SCLK to ET''



To compute ET seconds past J2000 for a given SCLK string, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-82)
   Time format               Spacecraft clock string
   Input time                1465674964.105
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   140254384.183430
Either the input SCLK time or these output ET seconds past J2000 should be used as the input time in all remaining ``In-situ Sensing'' lesson steps in order for WGC to compute values matching the results provided in the programming lesson. The output ET seconds may be saved for future use in the WGC ``Saved Values'' area by simply clicking on them with the left mouse button. The saved value can then be drag-n-dropped from the ``Saved Values'' area into the empty ``Time:'' box in the next calculation.



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Step-3: ``Spacecraft State''



To compute the geometric state of the CASSINI spacecraft with respect to the Sun in the Ecliptic frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    CASSINI
   Observer type             Object
   Observer                  SUN
   Reference frame           ECLIPJ2000
   Light propagation         No correction
   Time system               TDB
   Time format               Seconds past J2000
   Input time                140254384.183430
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   -376599061.91656125
   1294487780.92915730
   -7064853.05469811
   -5.16422619
   0.80171891
   0.04060306


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Step-4: ``Sun Direction''



To compute the apparent direction of the Sun in the INMS frame, specify/select the following inputs in the ``Pointing Direction'' calculation:

   Calculation type          Pointing Direction
   Direction type            Position
   Target                    SUN
   Observer                  CASSINI
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Use anti-vector           No
   Time system               TDB
   Time format               Seconds past J2000
   Input time                140254384.183430
   Reference frame           CASSINI_INMS
   Vector magnitude          Unit
   Coordinate system         Rectangular
WGC will return the following unit vector along the Sun direction:

   -0.29020402
   0.88163119
   0.37216672


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Step-5: ``Sub-Spacecraft Point''



To compute the planetocentric longitude and latitude of the CASSINI sub-spacecraft point on Phoebe, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    PHOEBE
   Reference frame           IAU_PHOEBE
   Observer                  CASSINI
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               TDB
   Time format               Seconds past J2000
   Input time                140254384.183430
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   23.42315899
   3.70979740
WGC cannot compute the direction from the CASSINI spacecraft to the sub-spacecraft point in the INMS frame.



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Step-6: ``Spacecraft Velocity''



To compute the CASSINI spacecraft velocity with respect to Phoebe in the INMS frame, specify/select the following inputs in the ``Pointing Direction'' calculation:

   Calculation type          Pointing Direction
   Direction type            Velocity
   Target                    CASSINI
   Observer                  Phoebe
   Reference frame           J2000
   Light propagation         No correction
   Use anti-vector           No
   Time system               TDB
   Time format               Seconds past J2000
   Input time                140254384.183430
   Reference frame           CASSINI_INMS
   Vector magnitude          Unit
   Coordinate system         Rectangular
WGC will return the following unit vector along the velocity direction:

   0.39578487
   -0.29280766
   0.87041255


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``BepiColombo MPO In-situ Sensing'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - BepiColombo MPO In-situ Sensing Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Step-1: ``UTC to ET''



To compute ET seconds past J2000 for a given UTC string, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               UTC
   Time format               Calendar date and time
   Input time                2027 JAN 05 02:04:36
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   852386745.184030


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Step-2: ``SCLK to ET''



To compute ET seconds past J2000 for a given SCLK string, specify/select the following inputs in the ``Time Conversion'' calculation:

   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                863834674:28127
   Output time system        TDB
   Output time format        Seconds past J2000
WGC will return the following ET seconds past J2000:

   852386745.184040
The input SCLK time should be used as the input time in all remaining ``In-situ Sensing'' lesson steps in order for WGC to compute values matching the results provided in the programming lesson. The input SCLK time may be saved for future use in the WGC ``Saved Values'' area by simply clicking on it in the results table with the left mouse button. The saved value can then be drag-n-dropped from the ``Saved Values'' area into the empty ``Time:'' box in the next calculation.



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Step-3: ``Spacecraft State''



To compute the geometric state of the BepiColombo MPO spacecraft with respect to the Sun in the Ecliptic frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    BEPICOLOMBO MPO
   Observer type             Object
   Observer                  SUN
   Reference frame           ECLIPJ2000
   Light propagation         No correction
   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                863834674:28127
   State representation      Rectangular
WGC will return the following state vector, km and km/s:

   23439067.89610513
   -62315194.63894688
   -7240868.73859754
   35.79932269
   18.15198781
   0.89057038


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Step-4: ``Sun Direction''



To compute the apparent direction of the Sun in the SERENA STROFIO +X Buffle frame, specify/select the following inputs in the ``Pointing Direction'' calculation:

   Calculation type          Pointing Direction
   Direction type            Position
   Target                    SUN
   Observer                  BEPICOLOMBO MPO
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Use anti-vector           No
   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                863834674:28127
   Reference frame           MPO_SERENA_STROFIO+X
   Vector magnitude          Unit
   Coordinate system         Rectangular
WGC will return the following unit vector along the Sun direction:

   0.71193730
   0.54950539
   -0.43725177


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Step-5: ``Sub-Spacecraft Point''



To compute the planetocentric longitude and latitude of the BEPICOLOMBO MPO sub-spacecraft point on Mercury, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MERCURY
   Reference frame           IAU_MERCURY
   Observer                  BEPICOLOMBO MPO
   Sub-point type            Near point: ellipsoid
   Light propagation         No correction
   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                863834674:28127
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   17.94407694
   31.52107152
WGC cannot compute the direction from the BepiColombo MPO spacecraft to the sub-spacecraft point in the SERENA STROFIO +X Buffle frame.



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Step-6: ``Spacecraft Velocity''



To compute the BepiColombo MPO spacecraft velocity with respect to Mercury in the SERENA STROFIO +X Buffle frame, specify/select the following inputs in the ``Pointing Direction'' calculation:

   Calculation type          Pointing Direction
   Direction type            Velocity
   Target                    BEPICOLOMBO MPO
   Observer                  MERCURY
   Reference frame           J2000
   Light propagation         No correction
   Use anti-vector           No
   Time system               Spacecraft clock (SCLK=-121)
   Time format               Spacecraft clock string
   Input time                863834674:28127
   Reference frame           MPO_SERENA_STROFIO+X
   Vector magnitude          Unit
   Coordinate system         Rectangular
WGC will return the following unit vector along the velocity direction, deg:

   0.10574453
   9.33475590E-06
   0.99439333


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``Mars Express Geometric Event Finding'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - Mars Express Geometric Event Finding Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.

Make sure to unload the ``Ground Stations Kernels'' kernel set if it is pre-loaded by default as this kernel set contains a duplicate definition of the ``DSS-14_TOPO'' frame that may trigger a SPICE error if loaded together with the lesson kernel set.



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Find View Periods



To find the set of time intervals when the Mars Express (MEX) is visible from the DSN station DSS-14, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      MEX
   Observer                    DSS-14
   Reference frame             DSS-14_TOPO
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Stellar aberration          Corrected for stellar aberration
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2004 MAY 2 to 2004 MAY 6
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude is greater than 6
   Output time unit            hours
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following interval start and stop times:

   2004-05-02 00:00:00.000000 TDB
   2004-05-02 05:35:03.096376 TDB
 
   2004-05-02 16:09:14.078641 TDB
   2004-05-03 05:33:57.257816 TDB
 
   2004-05-03 16:08:02.279561 TDB
   2004-05-04 05:32:50.765340 TDB
 
   2004-05-04 16:06:51.259358 TDB
   2004-05-05 05:31:43.600189 TDB
 
   2004-05-05 16:05:40.994061 TDB
   2004-05-06 00:00:00.000000 TDB
Make sure to save these output intervals in the WGC ``Saved Values'' area using the ``Save All Intervals'' button to make them available for use as input to the next step of the lesson.



Top

Find Times when Target is Visible



To find the set of time intervals when the Mars Express Orbiter (MEX) spacecraft is visible from the DSN station DSS-14 and is not occulted by Mars modeled as an ellipsoid, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MARS
   Front body shape            Ellipsoid
   Front body frame            IAU_MARS
   Back body                   MEX
   Back body shape             Point
   Back body frame
   Observer                    DSS-14
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2004-05-02 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2004-05-02 00:00:00.000000 TDB
   2004-05-02 04:49:30.827635 TDB
 
   2004-05-02 16:09:14.078641 TDB
   2004-05-02 20:00:22.514122 TDB
 
   2004-05-02 21:01:38.222068 TDB
   2004-05-03 03:35:42.256777 TDB
 
   2004-05-03 04:36:42.484694 TDB
   2004-05-03 05:33:57.257816 TDB
 
   2004-05-03 16:08:02.279561 TDB
   2004-05-03 18:46:26.013964 TDB
 
   2004-05-03 19:46:54.618795 TDB
   2004-05-04 02:21:44.562990 TDB
 
   2004-05-04 03:21:56.347988 TDB
   2004-05-04 05:32:50.765340 TDB
 
   2004-05-04 16:06:51.259358 TDB
   2004-05-04 17:32:25.809031 TDB
 
   2004-05-04 18:32:05.975318 TDB
   2004-05-05 01:07:48.264966 TDB
 
   2004-05-05 02:07:11.601765 TDB
   2004-05-05 05:31:43.600189 TDB
 
   2004-05-05 16:05:40.994061 TDB
   2004-05-05 16:18:35.560693 TDB
 
   2004-05-05 17:17:27.717224 TDB
   2004-05-05 23:54:04.672052 TDB
To find the set of time intervals when the Mars Express Orbiter (MEX) spacecraft is visible from the DSN station DSS-14 and is not occulted by Mars modeled using a DSK shape model, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MARS
   Front body shape            DSK model
   Front body frame            IAU_MARS
   Back body                   MEX
   Back body shape             Point
   Observer                    DSS-14
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2004-05-02 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2004-05-02 00:00:00.000000 TDB
   2004-05-02 04:49:32.645582 TDB
 
   2004-05-02 16:09:14.078641 TDB
   2004-05-02 20:00:23.980386 TDB
 
   2004-05-02 21:01:43.206810 TDB
   2004-05-03 03:35:44.140275 TDB
 
   2004-05-03 04:36:46.868950 TDB
   2004-05-03 05:33:57.257816 TDB
 
   2004-05-03 16:08:02.279561 TDB
   2004-05-03 18:46:27.306582 TDB
 
   2004-05-03 19:46:59.734382 TDB
   2004-05-04 02:21:46.574959 TDB
 
   2004-05-04 03:22:00.862241 TDB
   2004-05-04 05:32:50.765340 TDB
 
   2004-05-04 16:06:51.259358 TDB
   2004-05-04 17:32:27.118804 TDB
 
   2004-05-04 18:32:11.057061 TDB
   2004-05-05 01:07:50.061373 TDB
 
   2004-05-05 02:07:16.253201 TDB
   2004-05-05 05:31:43.600189 TDB
 
   2004-05-05 16:05:40.994061 TDB
   2004-05-05 16:18:36.994871 TDB
 
   2004-05-05 17:17:32.385773 TDB
   2004-05-05 23:54:06.221724 TDB


Top

Extra Credit



1. To find times when Mars Express orbiter (MEX) crosses Mars' equator, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      MARS EXPRESS
   Observer                    MARS
   Reference frame             IAU_MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2004 MAY 02 to 2004 MAY 06
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude equals 0
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2004-05-02 05:00:08.334792 TDB
   2004-05-02 06:15:13.074957 TDB
   2004-05-02 12:35:14.856242 TDB
   2004-05-02 13:50:09.161841 TDB
   2004-05-02 20:10:24.439170 TDB
   2004-05-02 21:25:10.344246 TDB
   2004-05-03 03:45:26.758446 TDB
   2004-05-03 05:00:04.086901 TDB
   2004-05-03 11:20:32.419618 TDB
   2004-05-03 12:34:57.968562 TDB
   2004-05-03 18:55:34.883629 TDB
   2004-05-03 20:09:53.063063 TDB
   2004-05-04 02:30:35.509603 TDB
   2004-05-04 03:44:42.753445 TDB
   2004-05-04 10:05:41.638033 TDB
   2004-05-04 11:19:38.397433 TDB
   2004-05-04 17:40:41.405725 TDB
   2004-05-04 18:54:31.413477 TDB
   2004-05-05 01:15:45.967991 TDB
   2004-05-05 02:29:25.294886 TDB
   2004-05-05 08:50:53.931352 TDB
   2004-05-05 10:04:26.915886 TDB
   2004-05-05 16:25:58.350272 TDB
   2004-05-05 17:39:23.889937 TDB
2. To find times when Mars Express orbiter (MEX) is at periapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      MARS EXPRESS
   Observer                    MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2004 MAY 02 to 2004 MAY 06
   Step                        300 seconds
   Coordinate condition        Distance is local minimum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2004-05-02 05:57:51.000411 TDB
   2004-05-02 13:32:43.325958 TDB
   2004-05-02 21:07:41.124293 TDB
   2004-05-03 04:42:30.648154 TDB
   2004-05-03 12:17:21.143198 TDB
   2004-05-03 19:52:12.267643 TDB
   2004-05-04 03:26:57.755816 TDB
   2004-05-04 11:01:49.826895 TDB
   2004-05-04 18:36:38.448012 TDB
   2004-05-05 02:11:28.558226 TDB
   2004-05-05 09:46:26.309109 TDB
   2004-05-05 17:21:18.875493 TDB
3. To find times when Mars Express orbiter (MEX) is at apoapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      MARS EXPRESS
   Observer                    MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2004 MAY 02 to 2004 MAY 06
   Step                        300 seconds
   Coordinate condition        Distance is local maximum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2004-05-02 02:10:24.948283 TDB
   2004-05-02 09:45:19.189323 TDB
   2004-05-02 17:20:14.194854 TDB
   2004-05-03 00:55:07.633360 TDB
   2004-05-03 08:29:57.890652 TDB
   2004-05-03 16:04:48.524492 TDB
   2004-05-03 23:39:36.745574 TDB
   2004-05-04 07:14:25.662870 TDB
   2004-05-04 14:49:15.904704 TDB
   2004-05-04 22:24:05.351784 TDB
   2004-05-05 05:58:59.270665 TDB
   2004-05-05 13:33:54.433201 TDB
   2004-05-05 21:08:50.211003 TDB


Top

``ExoMars-16 TGO Geometric Event Finding'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - ExoMars 2016 Geometric Event Finding Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Find View Periods



To find the set of time intervals when the ExoMars-16 TGO (TGO) is visible from the ESA station NEW_NORCIA, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      EXOMARS 2016 TGO
   Observer                    NEW_NORCIA
   Reference frame             NEW_NORCIA_TOPO
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Stellar aberration          Corrected for stellar aberration
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2018 JUN 10 to 2018 JUN 14
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude is greater than 6
   Output time unit            hours
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following interval start and stop times:

   2018-06-10 00:00:00.000000 TDB
   2018-06-10 02:11:17.355621 TDB
 
   2018-06-10 13:19:58.777464 TDB
   2018-06-11 02:08:16.008548 TDB
 
   2018-06-11 13:16:50.542539 TDB
   2018-06-12 02:05:12.548825 TDB
 
   2018-06-12 13:13:38.573032 TDB
   2018-06-13 02:02:06.618874 TDB
 
   2018-06-13 13:10:23.432464 TDB
   2018-06-14 00:00:00.000000 TDB
Make sure to save these output intervals in the WGC ``Saved Values'' area using the ``Save All Intervals'' button to make them available for use as input to the next step of the lesson.



Top

Find Times when Target is Visible



To find the set of time intervals when the ExoMars-16 TGO Orbiter (TGO) spacecraft is visible from the ESA station NEW_NORCIA and and is not occulted by Mars modeled as an ellipsoid, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MARS
   Front body shape            Ellipsoid
   Front body frame            IAU_MARS
   Back body                   EXOMARS 2016 TGO
   Back body shape             Point
   Observer                    NEW_NORCIA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2018-06-10 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2018-06-10 00:00:00.000000 TDB
   2018-06-10 01:00:30.640614 TDB
 
   2018-06-10 01:41:03.610048 TDB
   2018-06-10 02:11:17.355621 TDB
 
   2018-06-10 13:28:28.785788 TDB
   2018-06-10 14:45:38.197853 TDB
 
   2018-06-10 15:26:21.981505 TDB
   2018-06-10 16:43:32.192863 TDB
 
   2018-06-10 17:24:17.290058 TDB
   2018-06-10 18:41:27.535612 TDB
 
   2018-06-10 19:22:13.628023 TDB
   2018-06-10 20:39:21.785693 TDB
 
   2018-06-10 21:20:08.856427 TDB
   2018-06-10 22:37:12.445420 TDB
 
   2018-06-10 23:18:00.834325 TDB
   2018-06-11 00:35:01.034340 TDB
 
   2018-06-11 01:15:50.883961 TDB
   2018-06-11 02:08:16.008548 TDB
 
   2018-06-11 13:16:50.542539 TDB
   2018-06-11 14:20:09.789544 TDB
 
   2018-06-11 15:01:08.370780 TDB
   2018-06-11 16:18:03.385855 TDB
 
   2018-06-11 16:59:03.014503 TDB
   2018-06-11 18:15:58.739454 TDB
 
   2018-06-11 18:56:59.199542 TDB
   2018-06-11 20:13:54.308303 TDB
 
   2018-06-11 20:54:55.301168 TDB
   2018-06-11 22:11:47.045226 TDB
 
   2018-06-11 22:52:48.925002 TDB
   2018-06-12 00:09:35.868266 TDB
 
   2018-06-12 00:50:39.046685 TDB
   2018-06-12 02:05:12.548825 TDB
 
   2018-06-12 13:13:38.573032 TDB
   2018-06-12 13:54:43.524958 TDB
 
   2018-06-12 14:35:54.054008 TDB
   2018-06-12 15:52:36.256662 TDB
 
   2018-06-12 16:33:47.502777 TDB
   2018-06-12 17:50:30.988537 TDB
 
   2018-06-12 18:31:42.896589 TDB
   2018-06-12 19:48:26.827964 TDB
 
   2018-06-12 20:29:39.039169 TDB
   2018-06-12 21:46:20.933464 TDB
 
   2018-06-12 22:27:33.596215 TDB
   2018-06-12 23:44:11.473471 TDB
 
   2018-06-13 00:25:24.992296 TDB
   2018-06-13 01:42:00.777360 TDB
 
   2018-06-13 13:10:23.432464 TDB
   2018-06-13 13:29:19.789157 TDB
 
   2018-06-13 14:10:38.985039 TDB
   2018-06-13 15:27:11.882834 TDB
 
   2018-06-13 16:08:31.566611 TDB
   2018-06-13 17:25:06.068241 TDB
 
   2018-06-13 18:06:26.219824 TDB
   2018-06-13 19:23:01.820444 TDB
 
   2018-06-13 20:04:22.175372 TDB
   2018-06-13 21:20:57.296111 TDB
 
   2018-06-13 22:02:17.650959 TDB
   2018-06-13 23:18:49.624491 TDB
To find the set of time intervals when the ExoMars-16 TGO Orbiter (TGO) spacecraft is visible from the ESA station NEW_NORCIA and and is not occulted by Mars modeled using a DSK shape model, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MARS
   Front body shape            DSK model
   Front body frame            IAU_MARS
   Back body                   EXOMARS 2016 TGO
   Back body shape             Point
   Observer                    NEW_NORCIA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2018-06-10 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2018-06-10 00:00:00.000000 TDB
   2018-06-10 01:00:28.220807 TDB
 
   2018-06-10 01:41:01.646917 TDB
   2018-06-10 02:11:17.355621 TDB
 
   2018-06-10 13:28:26.224303 TDB
   2018-06-10 14:45:35.493195 TDB
 
   2018-06-10 15:26:19.616482 TDB
   2018-06-10 16:43:28.927026 TDB
 
   2018-06-10 17:24:15.708129 TDB
   2018-06-10 18:41:24.797353 TDB
 
   2018-06-10 19:22:12.239603 TDB
   2018-06-10 20:39:19.310010 TDB
 
   2018-06-10 21:20:07.177145 TDB
   2018-06-10 22:37:09.488415 TDB
 
   2018-06-10 23:17:58.789177 TDB
   2018-06-11 00:34:58.698530 TDB
 
   2018-06-11 01:15:48.932135 TDB
   2018-06-11 02:08:16.008548 TDB
 
   2018-06-11 13:16:50.542539 TDB
   2018-06-11 14:20:07.002550 TDB
 
   2018-06-11 15:01:05.889750 TDB
   2018-06-11 16:18:00.245245 TDB
 
   2018-06-11 16:59:00.815555 TDB
   2018-06-11 18:15:55.713823 TDB
 
   2018-06-11 18:56:57.742755 TDB
   2018-06-11 20:13:51.980832 TDB
 
   2018-06-11 20:54:53.740948 TDB
   2018-06-11 22:11:44.029460 TDB
 
   2018-06-11 22:52:47.021765 TDB
   2018-06-12 00:09:33.513615 TDB
 
   2018-06-12 00:50:37.057576 TDB
   2018-06-12 02:05:12.548825 TDB
 
   2018-06-12 13:13:38.573032 TDB
   2018-06-12 13:54:41.265138 TDB
 
   2018-06-12 14:35:51.639820 TDB
   2018-06-12 15:52:34.091993 TDB
 
   2018-06-12 16:33:45.105220 TDB
   2018-06-12 17:50:29.020626 TDB
 
   2018-06-12 18:31:41.100405 TDB
   2018-06-12 19:48:23.878666 TDB
 
   2018-06-12 20:29:37.591528 TDB
   2018-06-12 21:46:18.430557 TDB
 
   2018-06-12 22:27:31.911087 TDB
   2018-06-12 23:44:08.681952 TDB
 
   2018-06-13 00:25:22.967320 TDB
   2018-06-13 01:41:58.417366 TDB
 
   2018-06-13 13:10:23.432464 TDB
   2018-06-13 13:29:18.021452 TDB
 
   2018-06-13 14:10:36.866862 TDB
   2018-06-13 15:27:09.686654 TDB
 
   2018-06-13 16:08:29.188852 TDB
   2018-06-13 17:25:04.013047 TDB
 
   2018-06-13 18:06:23.940576 TDB
   2018-06-13 19:22:59.754402 TDB
 
   2018-06-13 20:04:20.668606 TDB
   2018-06-13 21:20:54.998971 TDB
 
   2018-06-13 22:02:16.162693 TDB
   2018-06-13 23:18:47.458050 TDB


Top

Extra Credit



1. To find times when ExoMars-16 TGO (TGO) crosses Mars' equator, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      EXOMARS 2016 TGO
   Observer                    MARS
   Reference frame             IAU_MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2018 JUN 10 to 2018 JUN 11
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude equals 0
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2018-06-10 00:14:08.836580 TDB
   2018-06-10 01:12:34.582095 TDB
   2018-06-10 02:12:00.375370 TDB
   2018-06-10 03:10:28.808573 TDB
   2018-06-10 04:09:53.955311 TDB
   2018-06-10 05:08:23.919392 TDB
   2018-06-10 06:07:48.630669 TDB
   2018-06-10 07:06:17.539430 TDB
   2018-06-10 08:05:42.659963 TDB
   2018-06-10 09:04:09.120521 TDB
   2018-06-10 10:03:34.270188 TDB
   2018-06-10 11:01:59.269625 TDB
   2018-06-10 12:01:22.866520 TDB
   2018-06-10 12:59:49.352117 TDB
   2018-06-10 13:59:13.289772 TDB
   2018-06-10 14:57:41.242004 TDB
   2018-06-10 15:57:07.576976 TDB
   2018-06-10 16:55:35.266038 TDB
   2018-06-10 17:55:02.773235 TDB
   2018-06-10 18:53:30.271499 TDB
   2018-06-10 19:52:56.383285 TDB
   2018-06-10 20:51:23.966229 TDB
   2018-06-10 21:50:47.729319 TDB
   2018-06-10 22:49:14.385397 TDB
   2018-06-10 23:48:37.583974 TDB
2. To find times when ExoMars-16 TGO (TGO) is at periapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      EXOMARS 2016 TGO
   Observer                    MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2018 JUN 10 to 2018 JUN 11
   Step                        300 seconds
   Coordinate condition        Distance is local minimum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2018-06-10 00:43:06.357819 TDB
   2018-06-10 02:40:47.168872 TDB
   2018-06-10 04:38:45.496250 TDB
   2018-06-10 06:36:32.706773 TDB
   2018-06-10 08:34:10.548681 TDB
   2018-06-10 10:31:49.108636 TDB
   2018-06-10 12:29:20.342207 TDB
   2018-06-10 14:27:07.089996 TDB
   2018-06-10 16:25:36.081463 TDB
   2018-06-10 18:24:02.653942 TDB
   2018-06-10 20:22:23.184793 TDB
   2018-06-10 22:20:12.453735 TDB
3. To find times when ExoMars-16 TGO (TGO) is at apoapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      EXOMARS 2016 TGO
   Observer                    MARS
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2018 JUN 10 to 2018 JUN 11
   Step                        300 seconds
   Coordinate condition        Distance is local maximum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2018-06-10 01:41:44.632145 TDB
   2018-06-10 03:39:31.106999 TDB
   2018-06-10 05:37:22.115251 TDB
   2018-06-10 07:34:59.674318 TDB
   2018-06-10 09:32:25.708394 TDB
   2018-06-10 11:29:47.945538 TDB
   2018-06-10 13:27:30.200636 TDB
   2018-06-10 15:26:02.524463 TDB
   2018-06-10 17:24:37.842993 TDB
   2018-06-10 19:23:11.265220 TDB
   2018-06-10 21:21:13.530306 TDB
   2018-06-10 23:18:56.796575 TDB


Top

``KPLO Geometric Event Finding'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - KPLO Geometric Event Finding Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Find View Periods



To find the set of time intervals when the KPLO is visible from the KARI station KDSA, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      KOREA PATHFINDER LUNAR ORBITER
   Observer                    KDSA
   Reference frame             KDSA_TOPO
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Stellar aberration          Corrected for stellar aberration
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2021 JAN 02 to 2021 JAN 04 TDB
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude is greater than 6
   Output time unit            hours
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following interval start and stop times:

   2021-01-02 00:00:00.000000 TDB
   2021-01-02 00:29:04.809104 TDB
 
   2021-01-02 12:09:44.219078 TDB
   2021-01-03 01:06:51.294946 TDB
 
   2021-01-03 13:14:11.953416 TDB
   2021-01-04 00:00:00.000000 TDB
Make sure to save these output intervals in the WGC ``Saved Values'' area using the ``Save All Intervals'' button to make them available for use as input to the next step of the lesson.



Top

Find Times when Target is Visible



To find the set of time intervals when the KPLO Orbiter spacecraft is visible from the KARI station KDSA and and is not occulted by Moon modeled as an ellipsoid, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MOON
   Front body shape            Ellipsoid
   Front body frame            MOON_ME
   Back body                   KOREA PATHFINDER LUNAR ORBITER
   Back body shape             Point
   Observer                    KDSA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2021-01-02 00:00:00...
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2021-01-02 00:00:00.000000 TDB
   2021-01-02 00:10:09.889149 TDB
 
   2021-01-02 12:40:16.709927 TDB
   2021-01-02 13:53:22.951804 TDB
 
   2021-01-02 14:38:06.490360 TDB
   2021-01-02 15:51:01.342268 TDB
 
   2021-01-02 16:35:53.098803 TDB
   2021-01-02 17:48:38.156533 TDB
 
   2021-01-02 18:33:36.932715 TDB
   2021-01-02 19:46:13.245471 TDB
 
   2021-01-02 20:31:18.977103 TDB
   2021-01-02 21:43:47.009069 TDB
 
   2021-01-02 22:29:00.574638 TDB
   2021-01-02 23:41:20.248180 TDB
 
   2021-01-03 00:26:43.022041 TDB
   2021-01-03 01:06:51.294946 TDB
 
   2021-01-03 13:14:11.953416 TDB
   2021-01-03 13:24:44.929522 TDB
 
   2021-01-03 14:11:13.658468 TDB
   2021-01-03 15:22:24.978150 TDB
 
   2021-01-03 16:08:57.996438 TDB
   2021-01-03 17:20:04.038775 TDB
 
   2021-01-03 18:06:40.377391 TDB
   2021-01-03 19:17:42.133447 TDB
 
   2021-01-03 20:04:21.409086 TDB
   2021-01-03 21:15:19.693724 TDB
 
   2021-01-03 22:02:02.068830 TDB
   2021-01-03 23:12:57.440831 TDB
 
   2021-01-03 23:59:43.429772 TDB
   2021-01-04 00:00:00.000000 TDB
To find the set of time intervals when the KPLO Orbiter spacecraft is visible from the KARI station KDSA and and is not occulted by Moon modeled using a DSK shape model, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MOON
   Front body shape            DSK model
   Front body frame            MOON_ME
   Back body                   KOREA PATHFINDER LUNAR ORBITER
   Back body shape             Point
   Observer                    KDSA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2021-01-02 00:00:00...
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2021-01-02 00:00:00.000000 TDB
   2021-01-02 00:10:08.006832 TDB
 
   2021-01-02 12:40:16.852087 TDB
   2021-01-02 13:53:27.473483 TDB
 
   2021-01-02 14:38:06.251356 TDB
   2021-01-02 15:51:03.685211 TDB
 
   2021-01-02 16:35:52.094231 TDB
   2021-01-02 17:48:37.725860 TDB
 
   2021-01-02 18:33:36.119642 TDB
   2021-01-02 19:46:15.165413 TDB
 
   2021-01-02 20:31:18.110644 TDB
   2021-01-02 21:43:51.889714 TDB
 
   2021-01-02 22:28:59.525035 TDB
   2021-01-02 23:41:26.087095 TDB
 
   2021-01-03 00:26:41.518075 TDB
   2021-01-03 01:06:51.294946 TDB
 
   2021-01-03 13:14:11.953416 TDB
   2021-01-03 13:24:47.451517 TDB
 
   2021-01-03 14:11:12.626333 TDB
   2021-01-03 15:22:28.682591 TDB
 
   2021-01-03 16:08:56.940982 TDB
   2021-01-03 17:20:08.465709 TDB
 
   2021-01-03 18:06:39.012820 TDB
   2021-01-03 19:17:46.193336 TDB
 
   2021-01-03 20:04:20.411973 TDB
   2021-01-03 21:15:23.606861 TDB
 
   2021-01-03 22:02:01.131969 TDB
   2021-01-03 23:12:59.851984 TDB
 
   2021-01-03 23:59:42.474125 TDB
   2021-01-04 00:00:00.000000 TDB


Top

Extra Credit



1. To find times when KPLO crosses Moon' equator, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      KOREA PATHFINDER LUNAR ORBITER
   Observer                    MOON
   Reference frame             MOON_ME
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2021 JAN 02 to 2021 JAN 03
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude equals 0
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2021-01-02 00:29:09.291260 TDB
   2021-01-02 01:28:07.739313 TDB
   2021-01-02 02:26:53.378996 TDB
   2021-01-02 03:25:51.718417 TDB
   2021-01-02 04:24:37.370435 TDB
   2021-01-02 05:23:35.637643 TDB
   2021-01-02 06:22:21.229758 TDB
   2021-01-02 07:21:19.488355 TDB
   2021-01-02 08:20:04.908620 TDB
   2021-01-02 09:19:03.268286 TDB
   2021-01-02 10:17:48.394045 TDB
   2021-01-02 11:16:46.997406 TDB
   2021-01-02 12:15:31.710021 TDB
   2021-01-02 13:14:30.717714 TDB
   2021-01-02 14:13:14.874535 TDB
   2021-01-02 15:12:14.473830 TDB
   2021-01-02 16:10:57.866823 TDB
   2021-01-02 17:09:58.289834 TDB
   2021-01-02 18:08:40.644274 TDB
   2021-01-02 19:07:42.160572 TDB
   2021-01-02 20:06:23.192173 TDB
   2021-01-02 21:05:26.057974 TDB
   2021-01-02 22:04:05.537612 TDB
   2021-01-02 23:03:09.942854 TDB
2. To find times when KPLO is at periapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      KOREA PATHFINDER LUNAR ORBITER
   Observer                    MOON
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2021 JAN 02 to 2021 JAN 03
   Step                        300 seconds
   Coordinate condition        Distance is local minimum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2021-01-02 01:30:03.252209 TDB
   2021-01-02 03:27:47.175008 TDB
   2021-01-02 05:25:32.458516 TDB
   2021-01-02 07:23:19.666917 TDB
   2021-01-02 09:21:09.488858 TDB
   2021-01-02 11:19:02.272580 TDB
   2021-01-02 13:16:58.197678 TDB
   2021-01-02 15:14:57.534376 TDB
   2021-01-02 17:13:00.573722 TDB
   2021-01-02 19:11:07.149724 TDB
   2021-01-02 21:09:16.134309 TDB
   2021-01-02 23:07:26.025982 TDB
3. To find times when KPLO is at apoapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      KOREA PATHFINDER LUNAR ORBITER
   Observer                    MOON
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2021 JAN 02 to 2021 JAN 03
   Step                        300 seconds
   Coordinate condition        Distance is local maximum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2021-01-02 00:31:23.997068 TDB
   2021-01-02 02:29:07.494822 TDB
   2021-01-02 04:26:51.565647 TDB
   2021-01-02 06:24:36.779707 TDB
   2021-01-02 08:22:24.045804 TDB
   2021-01-02 10:20:13.799654 TDB
   2021-01-02 12:18:06.012411 TDB
   2021-01-02 14:16:00.876052 TDB
   2021-01-02 16:13:59.150197 TDB
   2021-01-02 18:12:01.620695 TDB
   2021-01-02 20:10:08.021442 TDB
   2021-01-02 22:08:16.917912 TDB


Top

``BepiColombo MPO Geometric Event Finding'' Hands-On Lesson Using WGC






Top

Kernels Used



Use the ``SPICE Class - BepiColombo MPO Geometric Event Finding Lesson Kernels'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do all steps in this lesson.



Top

Find View Periods



To find the set of time intervals when the BepiColombo MPO (MPO) is visible from the ESA station NEW_NORCIA, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      BEPICOLOMBO MPO
   Observer                    NEW_NORCIA
   Reference frame             NEW_NORCIA_TOPO
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Stellar aberration          Corrected for stellar aberration
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2027 JAN 03 to 2027 JAN 06
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude is greater than 6
   Output time unit            hours
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following interval start and stop times:

   2027-01-03 00:00:00.000000 TDB
   2027-01-03 10:58:25.063666 TDB
 
   2027-01-03 21:55:08.488015 TDB
   2027-01-04 11:01:14.279503 TDB
 
   2027-01-04 21:58:41.333765 TDB
   2027-01-05 11:04:00.020897 TDB
 
   2027-01-05 22:02:18.477689 TDB
   2027-01-06 00:00:00.000000 TDB
Make sure to save these output intervals in the WGC ``Saved Values'' area using the ``Save All Intervals'' button to make them available for use as input to the next step of the lesson.



Top

Find Times when Target is Visible



To find the set of time intervals when the BepiColombo MPO Orbiter (MPO) spacecraft is visible from the ESA station NEW_NORCIA and and is not occulted by MERCURY modeled as an ellipsoid, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MERCURY
   Front body shape            Ellipsoid
   Front body frame            IAU_MERCURY
   Back body                   BEPICOLOMBO MPO
   Back body shape             Point
   Observer                    NEW_NORCIA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2027-01-03 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2027-01-03 00:00:00.000000 TDB
   2027-01-03 01:28:03.419233 TDB
 
   2027-01-03 02:00:42.993632 TDB
   2027-01-03 03:49:50.750893 TDB
 
   2027-01-03 04:22:20.803992 TDB
   2027-01-03 06:11:38.050911 TDB
 
   2027-01-03 06:43:58.528879 TDB
   2027-01-03 08:33:25.499611 TDB
 
   2027-01-03 09:05:36.070506 TDB
   2027-01-03 10:55:12.991735 TDB
 
   2027-01-03 21:55:08.488015 TDB
   2027-01-03 22:44:11.490099 TDB
 
   2027-01-03 23:15:19.552983 TDB
   2027-01-04 01:05:59.339076 TDB
 
   2027-01-04 01:36:56.572342 TDB
   2027-01-04 03:27:47.253162 TDB
 
   2027-01-04 03:58:33.411659 TDB
   2027-01-04 05:49:35.238120 TDB
 
   2027-01-04 06:20:10.165230 TDB
   2027-01-04 08:11:23.310135 TDB
 
   2027-01-04 08:41:46.813607 TDB
   2027-01-04 10:33:11.480288 TDB
 
   2027-01-04 21:58:41.333765 TDB
   2027-01-04 22:22:13.911999 TDB
 
   2027-01-04 22:51:24.368524 TDB
   2027-01-05 00:44:02.576224 TDB
 
   2027-01-05 01:13:00.256137 TDB
   2027-01-05 03:05:51.406811 TDB
 
   2027-01-05 03:34:36.025883 TDB
   2027-01-05 05:27:40.260241 TDB
 
   2027-01-05 05:56:11.727894 TDB
   2027-01-05 07:49:29.298129 TDB
 
   2027-01-05 08:17:47.213618 TDB
   2027-01-05 10:11:18.377919 TDB
 
   2027-01-05 10:39:22.574622 TDB
   2027-01-05 11:04:00.020897 TDB
 
   2027-01-05 22:27:17.183790 TDB
   2027-01-06 00:00:00.000000 TDB
To find the set of time intervals when the BepiColombo MPO Orbiter (MPO) spacecraft is visible from the ESA station NEW_NORCIA and and is not occulted by MERCURY modeled using a DSK shape model, specify/select the following inputs in the ``Occultation Event Finder'' calculation:

   Occultation type            Any
   Front body                  MERCURY
   Front body shape            DSK model
   Front body frame            IAU_MERCURY
   Back body                   BEPICOLOMBO MPO
   Back body shape             Point
   Observer                    NEW_NORCIA
   Light propagation           To observer
   Light-time algorithm        Converged Newtonian
   Time system                 TDB
   Time format                 Calendar date and time
   Time windows                ["2027-01-03 00:00:00....
   Step                        300 seconds
   Output time unit            hours
   Complement result window    yes
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
To use the time intervals found by the previous step as the input to this calculation, select ``List of Intervals'' in the ``Input times:'' selector and drag and drop saved intervals from the ``Saved Values'' area into the empty ``List of intervals:'' box.

WGC will return the following interval start and stop times:

   2027-01-03 00:00:00.000000 TDB
   2027-01-03 01:28:03.202274 TDB
 
   2027-01-03 02:00:43.226282 TDB
   2027-01-03 03:49:50.589325 TDB
 
   2027-01-03 04:22:21.167426 TDB
   2027-01-03 06:11:37.927914 TDB
 
   2027-01-03 06:43:58.803080 TDB
   2027-01-03 08:33:25.452286 TDB
 
   2027-01-03 09:05:36.483005 TDB
   2027-01-03 10:55:13.005765 TDB
 
   2027-01-03 21:55:08.488015 TDB
   2027-01-03 22:44:11.836443 TDB
 
   2027-01-03 23:15:20.564990 TDB
   2027-01-04 01:05:59.788947 TDB
 
   2027-01-04 01:36:56.903679 TDB
   2027-01-04 03:27:47.794713 TDB
 
   2027-01-04 03:58:33.685170 TDB
   2027-01-04 05:49:35.857104 TDB
 
   2027-01-04 06:20:10.819543 TDB
   2027-01-04 08:11:23.843362 TDB
 
   2027-01-04 08:41:47.399395 TDB
   2027-01-04 10:33:12.291393 TDB
 
   2027-01-04 21:58:41.333765 TDB
   2027-01-04 22:22:13.969382 TDB
 
   2027-01-04 22:51:24.088513 TDB
   2027-01-05 00:44:02.498240 TDB
 
   2027-01-05 01:13:00.056223 TDB
   2027-01-05 03:05:51.377268 TDB
 
   2027-01-05 03:34:36.194296 TDB
   2027-01-05 05:27:40.400567 TDB
 
   2027-01-05 05:56:11.995943 TDB
   2027-01-05 07:49:29.743608 TDB
 
   2027-01-05 08:17:47.173986 TDB
   2027-01-05 10:11:18.893303 TDB
 
   2027-01-05 10:39:22.690895 TDB
   2027-01-05 11:04:00.020897 TDB
 
   2027-01-05 22:27:17.436008 TDB
   2027-01-06 00:00:00.000000 TDB


Top

Extra Credit



1. To find times when BepiColombo MPO (MPO) crosses MERCURY' equator, specify/select the following inputs in the ``Position Event Finder'' calculation:

   Target                      BEPICOLOMBO MPO
   Observer                    MERCURY
   Reference frame             IAU_MERCURY
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2027 JAN 03 to 2027 JAN 04
   Step                        300 seconds
   Coordinate system           Planetocentric
   Coordinate condition        Latitude equals 0
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2027-01-03 00:21:02.744334 TDB
   2027-01-03 01:34:39.885957 TDB
   2027-01-03 02:42:45.780223 TDB
   2027-01-03 03:56:22.917048 TDB
   2027-01-03 05:04:28.849131 TDB
   2027-01-03 06:18:06.007358 TDB
   2027-01-03 07:26:11.888263 TDB
   2027-01-03 08:39:49.081587 TDB
   2027-01-03 09:47:54.901012 TDB
   2027-01-03 11:01:32.084351 TDB
   2027-01-03 12:09:37.930329 TDB
   2027-01-03 13:23:15.135888 TDB
   2027-01-03 14:31:20.939808 TDB
   2027-01-03 15:44:58.128865 TDB
   2027-01-03 16:53:03.959515 TDB
   2027-01-03 18:06:41.171174 TDB
   2027-01-03 19:14:46.962115 TDB
   2027-01-03 20:28:24.150065 TDB
   2027-01-03 21:36:29.935243 TDB
   2027-01-03 22:50:07.114962 TDB
   2027-01-03 23:58:12.944905 TDB
2. To find times when BepiColombo MPO (MPO) is at periapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      BEPICOLOMBO MPO
   Observer                    MERCURY
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2027 JAN 03 to 2027 JAN 04
   Step                        300 seconds
   Coordinate condition        Distance is local minimum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2027-01-03 00:18:33.937597 TDB
   2027-01-03 02:40:16.998455 TDB
   2027-01-03 05:01:59.964812 TDB
   2027-01-03 07:23:43.026843 TDB
   2027-01-03 09:45:25.991310 TDB
   2027-01-03 12:07:09.042682 TDB
   2027-01-03 14:28:52.095744 TDB
   2027-01-03 16:50:35.082444 TDB
   2027-01-03 19:12:18.042779 TDB
   2027-01-03 21:34:01.097809 TDB
   2027-01-03 23:55:44.079910 TDB
3. To find times when BepiColombo MPO (MPO) is at apoapsis, specify/select the following inputs in the ``Distance Event Finder'' calculation:

   Target                      BEPICOLOMBO MPO
   Observer                    MERCURY
   Light propagation           No correction
   Time system                 TDB
   Time format                 Calendar date and time
   Time range                  2027 JAN 03 to 2027 JAN 04
   Step                        300 seconds
   Coordinate condition        Distance is local maximum
   Output time unit            seconds
   Complement result window    no
   Result interval adjustment  No adjustment
   Result interval filtering   No filtering
WGC will return the following times:

   2027-01-03 01:29:25.529845 TDB
   2027-01-03 03:51:08.495185 TDB
   2027-01-03 06:12:51.561811 TDB
   2027-01-03 08:34:34.611548 TDB
   2027-01-03 10:56:17.595681 TDB
   2027-01-03 13:18:00.653133 TDB
   2027-01-03 15:39:43.611529 TDB
   2027-01-03 18:01:26.677944 TDB
   2027-01-03 20:23:09.638216 TDB
   2027-01-03 22:44:52.618672 TDB


Top

``Binary PCK'' Hands-On Lesson Using WGC






Top

Moon rotation (mrotat)



Use the ``SPICE Class - Binary PCK Lesson Kernels (Moon)'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do this step in this lesson.

To compute the Moon-Earth direction using the low accuracy PCK and the IAU_MOON frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  MOON
   Reference frame           IAU_MOON
   Light propagation         To observer
   Light-time algorithm      Converged Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg:

   3.61310222
   -6.43834182
To compute the Moon-Earth direction using a high accuracy PCK and the MOON_ME frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  MOON
   Reference frame           MOON_ME
   Light propagation         To observer
   Light-time algorithm      Converged Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg:

   3.61122841
   -6.43950148
WGC cannot compute angular separation between the Moon-Earth direction vectors in the IAU_MOON and MOON_ME frames.

To compute the Moon-Earth direction using a high accuracy PCK and the MOON_PA frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    EARTH
   Observer type             Object
   Observer                  MOON
   Reference frame           MOON_PA
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg:

   3.59331861
   -6.41758189
WGC cannot compute angular separation between the Moon-Earth direction vectors in the MOON_ME and MOON_PA frames.

To compute the sub-Earth point on the Moon using a high accuracy PCK and the MOON_ME frame, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MOON
   Reference frame           MOON_ME
   Observer                  EARTH
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Converged Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   3.61141894
   -6.43950142
To compute the sub-Earth point on the Moon using a high accuracy PCK and the MOON_PA frame, specify/select the following inputs in the ``Sub-Observer Point'' calculation:

   Target                    MOON
   Reference frame           MOON_PA
   Observer                  EARTH
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Converged Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   3.59350886
   -6.41758182
WGC cannot compute the distance between the sub-Earth points computed in the MOON_ME and MOON_PA frames.



Top

Earth rotation (erotat)



Use the ``SPICE Class - Binary PCK Lesson Kernels (Earth)'' kernel set appearing near the bottom of the ``Kernel selection:'' menu to do this step in this lesson.

To compute the Earth-Moon direction using a low accuracy PCK and the IAU_EARTH frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MOON
   Observer type             Object
   Observer                  EARTH
   Reference frame           IAU_EARTH
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg:

   -35.49627162
   26.41695855
To compute the Earth-Moon direction using a high accuracy PCK and the ITRF93 frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MOON
   Observer type             Object
   Observer                  EARTH
   Reference frame           ITRF93
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg:

   -35.55428578
   26.41915557
WGC cannot compute the separation angle between the Earth-Moon vectors in IAU_EARTH and ITRF93 frames.

WGC cannot compute the IAU_EARTH and ITRF93 +X and +Z axis separation angles.

To compute the DSS-13-Moon azimuth and elevation using a high accuracy PCK and the DSS-13_TOPO frame, specify/select the following inputs in the ``State Vector'' calculation:

   Target type               Object
   Target                    MOON
   Observer type             Object
   Observer                  DSS-13
   Reference frame           DSS-13_TOPO
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   State representation      Planetocentric
WGC will return the following longitude and latitude, deg, that are equivalent to the azimuth (AZ=-LON) and elevation (EL=LAT):

   -72.16900637
   20.68948821
To compute the sub-solar point on Earth using a low accuracy PCK and the IAU_EARTH frame, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    EARTH
   Reference frame           IAU_EARTH
   Observer                  SUN
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   -177.10053149
   -22.91037699
To compute the sub-solar point on Earth using a high accuracy PCK and the ITRF93 frame, specify/select the following inputs in the ``Sub-Solar Point'' calculation:

   Target                    EARTH
   Reference frame           ITRF93
   Observer                  SUN
   Sub-point type            Near point: ellipsoid
   Light propagation         To observer
   Light-time algorithm      Newtonian
   Stellar aberration        Corrected for stellar aberration
   Time system               UTC
   Time format               Calendar date and time
   Input time                2007 JAN 1 00:00:00
   Position representation   Planetocentric
WGC will return the following longitude and latitude, deg:

   -177.15787351
   -22.91259307
WGC cannot compute the distance between the sub-solar points computed in the IAU_EARTH and ITRF93 frames.