JUNO Nominal Orientation CK File ============================================================= Created on October 26, 2014 by Boris Semenov, NAIF/JPL. Summary ------------------------------------------------------------- This CK contains the nominal Earth-pointed orientation of the JUNO spacecraft frame (JUNO_SPACECRAFT). Implementation Notes ------------------------------------------------------------- The JUNO_SPACECRAFT orientation is provided in this file using a combination of two kinds of segments: - segments providing the orientation of the JUNO spin axis (+Z) encapsulated in the orientation of the JUNO_SPIN_AXIS frame (frame ID -61900) relative to the J2000 inertial frame. These segments were generated using SPICE utility program "prediCkt" assuming the spin axis pointed at the Earth. - segments providing the rotation of the spacecraft about the spin axis encapsulated in the orientation of the JUNO_SPACECRAFT frame (frame ID -61000) relative to the JUNO_SPIN_AXIS frame. These segments were generated using SPICE utility program "msopck". See Appendix 2 below for details about these segments ("msopck" setup parameters, input, etc.). The segments generated by "prediCkt" and "msopck" were merged together into a single file (this file) using SPICE utility "dafcat". After merging the file was augmented with these comments. Modeling Notes ------------------------------------------------------------- Users of this CK file should be aware that: - the attitude in this file does not include Earth-repointing precessions - the spin axis pointing (+Z of the JUNO_SPIN_AXIS frame) was modeled to be within 0.25 degrees of JUNO-Earth vector. The ZX plane of the JUNO_SPIN_AXIS frame was modeled to always contain Ecliptic North, with the +X axis to be as close to it as possible. Coverage ------------------------------------------------------------- This file provides the continuous coverage for this period: Begin UTC End UTC ------------------------ ------------------------ 2014-10-26T02:47:17.817 2016-04-06T02:47:17.814 Related Kernels ------------------------------------------------------------- This was generated with and must be used together with the following kernels: Type Name ---- ------------------------------------------ LSK naif0010.tls SCLK JNO_SCLKSCET.00029.tsc FK juno_v02.tf (or later version) SPK spk_ref_131114_171017_140311.bsp Contact Information ------------------------------------------------------------- Contact Boris Semenov (Boris.Semenov@jpl.nasa.gov) if you have any questions regarding this file. Appendix 1: Information for Spin Axis Orientation Segments ============================================================= This C-kernels was produced using the SPICE program "prediCkt" on 2014-OCT-26 15:15:35. The following files were provided in support of the construction of the attitude given in this kernel. File Type Name ---- ------------------------------------------ SPK jup230.bsp SPK spk_ref_131114_171017_140311.bsp TEXT naif0010.tls This C-kernel matches the specification given below to 0.25000 degrees. The text kernel used to specify the orientation of structures included in this file is given below. ============================================================= Spin Axis Orientation ----------------------------------------------------------------- These segments contain the orientation data for the JUNO_SPIN_AXIS frame (frame ID -61900) relative to the J2000 inertial frame. These segments were generated using PREDICKT with the direction, orientation and schedule specifications provided below. Directions ----------------------------------------------------------------- TOSUN is the geometric position of the Sun relative to JUNO. TOEARTH is the geometric position of the Earth relative to JUNO. JUNOPOS is the geometric position of JUNO relative to Jupiter. JUNOVEL is the geometric velocity of JUNO relative to Jupiter. JUNOORB is the JUNO orbital momentum vector computed as the cross product of the JUNO position and velocity relative to Jupiter. JUNOORB14 is the JUNO orbital momentum vector rotated by -14 degrees about JUNOPOS. ECLIPN is the +Z axis (North pole) of the Ecliptic of J2000 inertial frame (ECLIPJ2000). \begindata DIRECTION_SPECS += ( 'TOSUN = POSITION OF SUN -' ) DIRECTION_SPECS += ( 'FROM JUNO -' ) DIRECTION_SPECS += ( 'CORRECTION NONE' ) DIRECTION_SPECS += ( 'TOEARTH = POSITION OF EARTH -' ) DIRECTION_SPECS += ( 'FROM JUNO -' ) DIRECTION_SPECS += ( 'CORRECTION NONE' ) DIRECTION_SPECS += ( 'JUNOPOS = POSITION OF JUNO -' ) DIRECTION_SPECS += ( 'FROM JUPITER -' ) DIRECTION_SPECS += ( 'CORRECTION NONE' ) DIRECTION_SPECS += ( 'JUNOVEL = VELOCITY OF JUNO -' ) DIRECTION_SPECS += ( 'FROM JUPITER -' ) DIRECTION_SPECS += ( 'CORRECTION NONE' ) DIRECTION_SPECS += ( 'JUNOORB = CROSS PRODUCT -' ) DIRECTION_SPECS += ( 'JUNOPOS JUNOVEL ' ) DIRECTION_SPECS += ( 'JUNOORB14 = ROTATE JUNOORB -' ) DIRECTION_SPECS += ( '-14 DEGREES -' ) DIRECTION_SPECS += ( 'ABOUT JUNOPOS ' ) DIRECTION_SPECS += ( 'ECLIPN = FIXED ECLIPJ2000 -' ) DIRECTION_SPECS += ( 'XYZ 0 0 1' ) \begintext Orientations ----------------------------------------------------------------- SUN_POINTED orientation has +Z along direction from JUNO to the Sun and Ecliptic North pole defining the ZX plane. EARTH_POINTED orientation has +Z along direction from JUNO to the Earth and Ecliptic North pole defining the ZX plane. MWR_ATTITUDE orientation has -Z along JUNO orbital momentum vector (POS cross VEL) and Ecliptic North pole defining the ZX plane. MWR_ATTITUDE_TILT14 orientation has -Z along JUNO orbital momentum vector (POS cross VEL) rotated by -14 degrees about POS and Ecliptic North pole defining the ZX plane. \begindata ORIENTATION_NAME += 'SUN_POINTED' PRIMARY += '+Z = TOSUN' SECONDARY += '+X = ECLIPN' BASE_FRAME += 'J2000' ORIENTATION_NAME += 'EARTH_POINTED' PRIMARY += '+Z = TOEARTH' SECONDARY += '+X = ECLIPN' BASE_FRAME += 'J2000' ORIENTATION_NAME += 'MWR_ATTITUDE' PRIMARY += '-Z = JUNOORB' SECONDARY += '+X = ECLIPN' BASE_FRAME += 'J2000' ORIENTATION_NAME += 'MWR_ATTITUDE_TILT14' PRIMARY += '-Z = JUNOORB14' SECONDARY += '+X = ECLIPN' BASE_FRAME += 'J2000' \begintext Schedule ----------------------------------------------------------------- Schedule is based on the following time-line: +Z-axis pointing direction Start End -------------------------- ------- ------- Earth 10/26/14 JOI-90d where: * JOI = 07/05/16 02:47:17 UTC Times is the keywords below are ETs. \begindata CK-SCLK = 61 CK-SPK = -61 CK-FRAMES = -61900 CK-61900ORIENTATION += 'EARTH_POINTED' CK-61900START += @2014-10-26/02:48:25 CK-61900STOP += @2016-04-06/02:48:25 \begintext Appendix 2: Information for Rotation About Spin Axis Segment ============================================================= ******************************************************************************** MSOPCK SETUP FILE: juno_sc_nom_141026_160406_v01_spin.setup ******************************************************************************** Spin Orientation ----------------------------------------------------------------- This segment contains the orientation data representing rotating of the JUNO_SPACECRAFT frame (frame ID -61000) about the JUNO_SPIN_AXIS frame (frame ID -61900): Spin Rate Start End --------- ------- ------- 2 rpm 10/26/14 JOI-90d where * JOI = 07/05/16 02:47:17 UTC The profile above was converted to the following input provided to MSOPCK to make this segment (the columns are: start UTC, stop UTC, initial orientation as three angles set to zero, and angular velocity representing CCW rotation about +Z): 2014-10-26/02:48:25TDB 2016-04-06/02:48:25TDB 0 0 0 0 0 0.20943951023932 The following MSOPCK setup parameters were used to generate this segment: \begindata LSK_FILE_NAME = 'naif0010.tls' SCLK_FILE_NAME = 'JNO_SCLKSCET.00029.tsc' FRAMES_FILE_NAME = 'juno_v02.tf' INTERNAL_FILE_NAME = 'JUNO NOMINAL SPIN ATTITUDE' CK_TYPE = 2 CK_SEGMENT_ID = 'JUNO NOMINAL SPIN ATTITUDE' INSTRUMENT_ID = -61000 REFERENCE_FRAME_NAME = 'JUNO_SPIN_AXIS' ANGULAR_RATE_PRESENT = 'YES' INPUT_TIME_TYPE = 'UTC' INPUT_DATA_TYPE = 'EULER ANGLES' EULER_ANGLE_UNITS = 'RADIANS' EULER_ROTATIONS_ORDER = ( 'X' 'Y' 'Z' ) ANGULAR_RATE_FRAME = 'INSTRUMENT' PRODUCER_ID = 'NAIF/JPL' \begintext ******************************************************************************** RUN-TIME OBTAINED META INFORMATION: ******************************************************************************** PRODUCT_CREATION_TIME = 2014-10-26T15:15:19 START_TIME = 2014-10-26T02:47:17.817 STOP_TIME = 2016-04-06T02:47:17.814 ******************************************************************************** INTERPOLATION INTERVALS IN THE FILE SEGMENTS: ******************************************************************************** SEG.SUMMARY: ID -61000, COVERG: 2014-10-26T02:47:17.817 2016-04-06T02:47:17.814 -------------------------------------------------------------------------------- 2014-10-26T02:47:17.817 2016-04-06T02:47:17.814 ******************************************************************************** End of comments.