KPL/PCK KPL/FK \begindata TEXT_KERNEL_ID += 'CASSINI_ROCKS V4.0 29 Oct 2003 PCK' \begintext Cassini Spacecraft Planetary Constants Kernel for small satellites ============================================================================== The TEXT_KERNEL_ID stores version information of loaded project text kernels. Each entry associated with the keyword is a string that consists of four parts: the kernel name, version, entry date, and type. For example, the ISS I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'CASSINI_ISS V0.0.0 29-SEPTEMBER-1999 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE This frame kernel contains the constants for small satellites (rocks) of Saturn. Refer to the notes at the bottom of the file for help, contacts, version history,references, and Cassini-specific parameter descriptions. Disclaimer - Many of the values described in this file are not known at the present time. For these cases 'placeholder' values have been supplied that are simply guesses. For the first attempt, values for Pan and Amalthea are used for all bodies. It is anticipated that updates to these quantities will occur as knowledge increases. Note that this file may be readily modified by you or anyone else. NAIF suggests that you inspect this file visually before proceeding with any critical or extended data processing. Body numbers and names ---------------------------------------------------------- The following the names and corresponding body ID codes for rocks found to date: 619 YMIR 620 PAALIAQ 621 TARVOS 622 IJIRAQ 623 SUTTUNG 624 KIVIUQ 625 MUNDILFARI 626 ALBIORIX 627 SKADI 628 ERRIAPO 629 SIARNAQ 630 THRYM YMIR ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 619 ) NAIF_BODY_NAME += ( 'YMIR' ) BODY619_RADII = ( 10 10 10 ) BODY619_POLE_RA = ( 40.58 -0.036 0. ) BODY619_POLE_DEC = ( 83.53 -0.004 0. ) BODY619_PM = ( 48.8 +626.0440000 0. ) BODY619_LONG_AXIS = ( 0. ) BODY619_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY619_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY619_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext PAALIAQ ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 620 ) NAIF_BODY_NAME += ( 'PAALIAQ' ) BODY620_RADII = ( 10 10 10 ) BODY620_POLE_RA = ( 40.58 -0.036 0. ) BODY620_POLE_DEC = ( 83.53 -0.004 0. ) BODY620_PM = ( 48.8 +626.0440000 0. ) BODY620_LONG_AXIS = ( 0. ) BODY620_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY620_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY620_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext TARVOS ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 621 ) NAIF_BODY_NAME += ( 'TARVOS' ) BODY621_RADII = ( 10 10 10 ) BODY621_POLE_RA = ( 40.58 -0.036 0. ) BODY621_POLE_DEC = ( 83.53 -0.004 0. ) BODY621_PM = ( 48.8 +626.0440000 0. ) BODY621_LONG_AXIS = ( 0. ) BODY621_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY621_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY621_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext IJIRAQ ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 622 ) NAIF_BODY_NAME += ( 'IJIRAQ' ) BODY622_RADII = ( 10 10 10 ) BODY622_POLE_RA = ( 40.58 -0.036 0. ) BODY622_POLE_DEC = ( 83.53 -0.004 0. ) BODY622_PM = ( 48.8 +626.0440000 0. ) BODY622_LONG_AXIS = ( 0. ) BODY622_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY622_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY622_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext SUTTUNG ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 623 ) NAIF_BODY_NAME += ( 'SUTTUNG' ) BODY623_RADII = ( 10 10 10 ) BODY623_POLE_RA = ( 40.58 -0.036 0. ) BODY623_POLE_DEC = ( 83.53 -0.004 0. ) BODY623_PM = ( 48.8 +626.0440000 0. ) BODY623_LONG_AXIS = ( 0. ) BODY623_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY623_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY623_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext KIVIUQ ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 624 ) NAIF_BODY_NAME += ( 'KIVIUQ' ) BODY624_RADII = ( 10 10 10 ) BODY624_POLE_RA = ( 40.58 -0.036 0. ) BODY624_POLE_DEC = ( 83.53 -0.004 0. ) BODY624_PM = ( 48.8 +626.0440000 0. ) BODY624_LONG_AXIS = ( 0. ) BODY624_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY624_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY624_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext MUNDILFARI ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 625 ) NAIF_BODY_NAME += ( 'MUNDILFARI' ) BODY625_RADII = ( 10 10 10 ) BODY625_POLE_RA = ( 40.58 -0.036 0. ) BODY625_POLE_DEC = ( 83.53 -0.004 0. ) BODY625_PM = ( 48.8 +626.0440000 0. ) BODY625_LONG_AXIS = ( 0. ) BODY625_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY625_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY625_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext ALBIORIX ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 626 ) NAIF_BODY_NAME += ( 'ALBIORIX' ) BODY626_RADII = ( 10 10 10 ) BODY626_POLE_RA = ( 40.58 -0.036 0. ) BODY626_POLE_DEC = ( 83.53 -0.004 0. ) BODY626_PM = ( 48.8 +626.0440000 0. ) BODY626_LONG_AXIS = ( 0. ) BODY626_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY626_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY626_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext SKADI ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 627 ) NAIF_BODY_NAME += ( 'SKADI' ) BODY627_RADII = ( 10 10 10 ) BODY627_POLE_RA = ( 40.58 -0.036 0. ) BODY627_POLE_DEC = ( 83.53 -0.004 0. ) BODY627_PM = ( 48.8 +626.0440000 0. ) BODY627_LONG_AXIS = ( 0. ) BODY627_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY627_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY627_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext ERRIAPO ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 628 ) NAIF_BODY_NAME += ( 'ERRIAPO' ) BODY628_RADII = ( 10 10 10 ) BODY628_POLE_RA = ( 40.58 -0.036 0. ) BODY628_POLE_DEC = ( 83.53 -0.004 0. ) BODY628_PM = ( 48.8 +626.0440000 0. ) BODY628_LONG_AXIS = ( 0. ) BODY628_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY628_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY628_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext SIARNAQ ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 629 ) NAIF_BODY_NAME += ( 'SIARNAQ' ) BODY629_RADII = ( 10 10 10 ) BODY629_POLE_RA = ( 40.58 -0.036 0. ) BODY629_POLE_DEC = ( 83.53 -0.004 0. ) BODY629_PM = ( 48.8 +626.0440000 0. ) BODY629_LONG_AXIS = ( 0. ) BODY629_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY629_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY629_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext THRYM ---------------------------------------------------------- \begindata NAIF_BODY_CODE += ( 630 ) NAIF_BODY_NAME += ( 'THRYM' ) BODY630_RADII = ( 10 10 10 ) BODY630_POLE_RA = ( 40.58 -0.036 0. ) BODY630_POLE_DEC = ( 83.53 -0.004 0. ) BODY630_PM = ( 48.8 +626.0440000 0. ) BODY630_LONG_AXIS = ( 0. ) BODY630_NUT_PREC_RA = ( -0.84 0. 0. 0. 0. 0. 0. 0. +0.01 ) BODY630_NUT_PREC_DEC = ( -0.36 0. 0. 0. 0. 0. 0. 0. 0. ) BODY630_NUT_PREC_PM = ( +0.76 0. 0. 0. 0. 0. 0. 0. -0.01 ) \begintext -------- URLS and CONTACTS Description of PCK format and contents can be found in NAIF's PCK "required reading" document, at: ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/ascii/individual_docs/pck.req NAIF tutorial on PCK formatting: ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Tutorials/office/individual_docs/16_ pck.ppt The Cassini PCK & ephemeris files can be found on the DOM, and at: ftp://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/pck Lee Elson, NAIF/JPL, (818)354-4223, Lee.Elson@jpl.nasa.gov Diane Conner, Cassini/JPL, (818)354-8586 Diane.Conner@jpl.nasa.gov -------- VERSION HISTORY 2003 Oct 29 (published) 1. Updated NAIF ids to body name mapping per reference 6 below. 2. Updated NAIF tutorial link 3. Added a reference to the new SPK file that goes with named rocks previously identified as s1-s12. By: Diane Conner 2003 May 29 (published) 1. Changed the body names to be Upper Case. 2. Changed LDPOOL to FURNISH, in the file loading instructions. By: Diane Conner 2003 Mar 21 (Not published) Initial 1. Rearranged data in the file to follow model developed by Mission Planning for the PCK file. 2. Added reference to corresponding SPK file. By: Diane Conner References ---------------------------------------------------------- 1. ``PCK-kernel Required Reading'' 2. ``Kernel Pool Required Reading'' 3. ``Frames Required Reading'' 4. Email from Diane Conner regarding targeting small satellites, or rocks, of Saturn. 5. Jacobson, R.A., SPK file sat125.bsp. 6. Sky & Telescope Magazine,(25th General Assembly of the International Astronomical Union, held from July 13-26 in Sydney, Australia) http://skyandtelescope.com/news/article_1012_1.asp Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this frame kernel must `load' the kernel, normally during program initialization. Loading the kernel associates data items with their names in a data structure called the `kernel pool'. The SPICELIB routine FURNISH loads a kernel file into the pool as shown below: CALL FURNSH ( ) FORTRAN version furnish_c (); C version In order for a program or subroutine to extract data from the pool, the SPICELIB routines GDPOOL and GIPOOL are used. See [2] for more details. This file was created and may be updated with a text editor or word processor. Assumptions ---------------------------------------------------------- This file contains constants used to model the orientation and shape of satellites. The orientation models express the direction of the pole and location of the prime meridian of a body as a function of time. The shape models represent all bodies as ellipsoids, using two equatorial radii and a polar radius. Spheroids and spheres are obtained when two or all three radii are equal. Orientation models ---------------------------------------------------------- All of the orientation models use three Euler angles to describe body orientation. To be precise, the Euler angles describe the orientation of the coordinate axes of the `Body Equator and Prime Meridian' system with respect to an inertial system. By default, the inertial system is J2000 (also called `EME2000'), but other frames can be specified in the file. See the PCK Required Reading for details. The first two angles, in order, are the right ascension and declination (henceforth RA and DEC) of the north pole of a body as a function of time. The third angle is the prime meridian location (represented by `W'), which is expressed as a rotation about the north pole, and is also a function of time. In this file, the time arguments in expressions always refer to Barycentric Dynamical Time (TDB), measured in centuries or days past the a reference epoch. By default, the reference epoch is the J2000 epoch, which is Julian ephemeris date 2451545.0, but other epochs can be specified in the file. See the PCK Required Reading for details. Example: 1991 IAU Model for orientation of the Earth. Note that these values are used as an example only; see the data area below for current values. alpha = 0.00 - 0.641 T ( RA ) 0 delta = 90.0 - 0.557 T ( DEC ) 0 W = 190.16 + 360.9856235 d ( Prime meridian ) T represents centuries past J2000 ( TDB ), d represents days past J2000 ( TDB ). In this file, the polynomials' coefficients above are assigned to the symbols BODY399_POLE_RA BODY399_POLE_DEC BODY399_POLE_PM as follows: BODY399_POLE_RA = ( 0. -0.641 0. ) BODY399_POLE_DEC = ( +90. -0.557 0. ) BODY399_PM = ( 190.16 +360.9856235 0. ) You'll see an additional symbol grouped with the ones listed here; it is BODY399_LONG_AXIS This term is zero for all bodies except Mars. It represents the offset between the longest axis of the triaxial ellipsoid used to model a body and the prime meridian of the body. In addition to polynomial terms, there are trigonometric terms. The arguments of the trigonometric terms are linear polynomials. In this file, we call the arguments of these trigonometric terms `nutation precession angles'. In this file, the polynomial expressions for the nutation precession angles are listed along with the planet's RA, DEC, and prime meridian terms. Example: 1991 IAU nutation precession angles for Earth. Note that these values are used as an example only; see the data area below for current values. E1 = 125.045 - 0.052992 d E2 = 250.090 - 0.105984 d E3 = 260.008 + 13.012001 d E4 = 176.625 + 13.340716 d E5 = 357.529 + 0.985600 d d represents days past J2000 ( TDB ) Because the NAIF Toolkit software expects the time units for the angles to be CENTURIES (as in the IAU models for most bodies--the Earth is an exception), the linear coefficients are scaled by 36525.0 in the assignments: BODY3_NUT_PREC_ANGLES = ( 125.045 -1935.5328 250.090 -3871.0656 260.008 475263.336525 176.625 487269.6519 357.529 35999.04 ) As stated above, the satellite orientation models use polynomial and trigonometric terms, where the arguments of the trigonometric terms are the `nutation precession angles'. Example: 1988 IAU values for the Moon. Again, these values are used as an example only; see the data area below for current values. alpha = 270.000 + 0.003 T - 3.878 sin(E1) - 0.120 sin(E2) 0 + 0.070 sin(E3) - 0.017 sin(E4) (RA) delta = 66.541 + 0.013 T + 1.543 cos(E1) + 0.024 cos(E2) 0 - 0.028 cos(E3) + 0.007 cos(E4) (DEC) W = 38.317 + 13.1763582 d + 3.558 sin(E1) + 0.121 sin(E2) - 0.064 sin(E3) + 0.016 sin(E4) + 0.025 sin(E5) ( Prime meridian ) d represents days past J2000. E1--E5 are the nutation precession angles. The polynomial terms are assigned to symbols by the statements BODY301_POLE_RA = ( 270.000 0.003 0. ) BODY301_POLE_DEC = ( +66.541 0.013 0. ) BODY301_PM = ( 38.317 +13.1763582 0. ) The coefficients of the trigonometric terms are assigned to symbols by the statements BODY301_NUT_PREC_RA = ( -3.878 -0.120 +0.070 -0.017 0. ) BODY301_NUT_PREC_DEC = ( +1.543 +0.024 -0.028 +0.007 0. ) BODY301_NUT_PREC_PM = ( +3.558 +0.121 -0.064 +0.016 +0.025 ) Note that for the RA and PM (prime meridian) assignments, the ith term is the coefficient of sin(Ei) in the expression used in the IAU model, while for the DEC assignment, the ith term is the coefficient of cos(Ei) in the expression used in the IAU model. NAIF software expects the models for satellite orientation to follow the form of the model shown here: the polynomial portions of the RA, DEC, and W expressions are expected to be quadratic, the trigonometric terms for RA and W (satellite prime meridian) are expected to be linear combinations of sines of nutation precession angles, the trigonometric terms for DEC are expected to be linear combinations of cosines of nutation precession angles, and the polynomials for the nutation precession angles themselves are expected to be linear. Shape models ---------------------------------------------------------- There is only one kind of shape model supported by the NAIF Toolkit software at present: the triaxial ellipsoid. The 2000 IAU report does not use any other models. For each body, three radii are listed: The first number is the largest equatorial radius (the length of the semi-axis containing the prime meridian), the second number is the smaller equatorial radius, and the third is the polar radius. Example: Radii of the Earth. BODY399_RADII = ( 6378.14 6378.14 6356.75 )