General information about SPICE PC-kernels ========================================== In the SPICE system, the PCK kernel provides orientation and shape information pertaining to extended solar system bodies such as the Sun, the planets, the natural satellites of the planets, comets, and asteroids. The most recent PC kernel file can always be obtained from NAIF/JPL. The purpose of the PCK kernels and associated software is to provide SPICE users with a convenient mechanism for supplying planetary physical constants to application programs. SPICE PCK routines are able to read files conforming to the PCK format and return to a calling application program both the data contained in such files and a small number of commonly used numeric quantities derived from the kernel data. For information on the SPICE toolkit and/or how to obtain it, please consult SPICE_INST.CAT and SOFT.CAT. Refer to the PCK.REQ document provided with the Toolkit to get more information on how to access PC-kernel data. Mars Express PCK Files ====================== This file describes the contents of the DATA/PCK directory of the Mars Express SPICE dataset. PCK files in this directory are either binary or text files. Text files are created manually with the information from mainly the 2000 IAU Report. Binary files are created from the information contained in the EOP files provided by IERS All binary PCK files (*.BPC) contained in this directory are unix binary files. These may be used as is (without format conversion) in a non-unix environment by using any recent version of the SPICE Toolkit (Version N0052 or later). All text PCK files (*.TPC) contained in this directory are unix text files. In order to be used in a non-UNIX environment, they have to be converted to the appropiate end-line convention. For example, the lines have to be terminated by a combination for Windows platforms. Current PC-Kernels Contained in this Data Set ============================================= The following PCK-kernels are provided in this data set: DE403_MASSES.TPC PCK file containing the masses for the sun, planets, satellites and planetary barycenters. These masses are given as ratios to of Solar GM to barycenter GM. PCKvvvvv.TPC PCK file containing the size, shape, radii and orientation constants for planets, satellites, Sun and some asteroids. In particular, data for Mars are contained in this file. Note that vvvvv is the version number, and that the kernel with the highest version number should be used. EARTH_[sdat]_[edat]_[pdat].BPC PCK file containing the orientation of the Earth as a function of time for the interval [sdat] to [edat]. From [pdat] the information contained in the file corresponds to predicted data. The rotational effects included are precession, nutation, rotation through true siderial time, polar motion and nutation corrections. MARS_IAU2000_V0.TPC This file contains constants used to model the orientation and shape of Mars and its satellites. Note that several versions of the same kernel can be provided. In that case, the file with the highest version number is the most up to date, and the one that should be used. Kernel File Details =================== The most detailed description of the data in a text PCK file is provided in metadata included inside the description area of the file. This information can be viewed using any text editor program. For binary files, the COMMNT utility included in the NAIF toolkit can be used to read the comments embedded in the kernel.