General information about SPICE SP-kernels ========================================== The purpose of the SP-kernel -- which stands for S(pacecraft) and P(lanet) Kernel -- is to allow ephemerides for any collection of solar system bodies, spacecraft or any other objects in 3D space to be combined under a common file format, and accessed by a common set of subroutines. SPK can be accessed by subroutines that are part of the SPICE library, the major component of the SPICE Toolkit. These subroutines can be integrated into user application programs. For information on the SPICE toolkit and/or how to obtain it, please consult SPICE_INST.CAT and SOFT.CAT. To use SP-kernels, a Leapseconds (LSK) is also required. To use SP-Kernels containing positions given relative to the non-inertial and project-defined frames, Frame Definitions Kernel (FK), Planetary Constants Kernel (PcK), and C-Kernel (CK) files are also required. Refer to the SPK.REQ document provided with the Toolkit to get more information on how to access SP-kernel data. Mars Express SPK Files ====================== This file describes the contents of the DATA/SPK directory of the Mars Express SPICE data server. Sources of kernels and naming convention: ---------------------------------------- - Kernels that are produced from the ESOC Flight Dynamics orbit products. These kernels are generated by an automated system located at ESAC, and operated by the MEX Science Ground Segment. The naming convention for these kernels is the same used in the orbit products used to create them; their filename start by 'OR'. - Kernels made by the Royal Observatory of Belgium, with ephemeris for Mars Express, calculated independently of the ESOC products. Their filename start by 'MEX_ROB'. - Kernels that store information about Solar System bodies, ground stations, etc. They are produced by NAIF/JPL, and keep their original name, but in capitals, to be PDS compliant. The contents and time span covered by any SPK file may be easily determined using the 'brief' utility program available in all copies of the SPICE Toolkit. Examples of usage: %brief %brief <*.bsp> %brief Descriptive information about how/why/when an SPK file was created is usually available in the 'comment area' of the file. This may be viewed using the 'commnt' utility program available in all copies of the SPICE Toolkit. Use the '-r' option to read the comments. Example: %commnt -r All binary SPK files (*.BSP) contained in this directory are unix binary files. These may be used as is (without format conversion) in a non-unix environment when using any recent version of the SPICE Toolkit (Version N0052 or later). Mars Express SPK-Kernels Contained in this Data Set =================================================== The following SPK-kernels are provided in this data set: DE405.BSP This file contains ephemeris data for the main Solar System bodies (planets barycenters, Mercury, Venus, Moon, Earth, Mars and Sun). It covers from Jan. 1950 to Jan. 2050. EARTHSTNS_FX_yymmdd.BSP Contains ephemeris data for NASA DSN stations relative to the terrestrial reference frame ITRF93. In the interest of flexibility, in this file the reference frame is labelled with the alias 'EARTH_FIXED'. Any application using this file must map the alias 'EARTH_FIXED' to either 'ITR93' or 'IAU_EARTH'. This file was released on yy-mm-dd. EARTHSTNS_ITRF93_yymmdd.BSP Contains ephemeris data for NASA DSN stations relative to the terrestrial reference frame label 'ITRF93'. This file was released on yy-mm-dd. MAR033_2000_2025.BSP This file contains ephemeris data for the Earth, Mars, their Barycenters, the Sun, Phobos and Deimos. It covers from January 2000 until January 2025. Althoug the most up to date JPL ephemeris information for Mars and its satellites is contained in MAR063.BSP, this file is provided for comparison with the one below. MAR033_HRSC_V03.BSP This file contains ephemeris data for Phobos and Deimos. The position of Phobos is shifted 5.5 seconds with respect to the position in the JPL/MAR033 ephemeris file, and the position of Deimos is shifted 40 seconds. This kernel takes into account the differences observed between the predicted positions in the JPL/MAR033 file and the observations made by HRSC. Refer to the comment area of the kernel for more information. MAR063.BSP This file contains ephemeris data for the Earth, Mars, their Barycenters, the Sun, Phobos and Deimos. It covers from Dec. 1962 until Jan. 2050. MARSAT_ESA_yymmdd_V01.BSP This file contains the Phobos and Deimos ephemerides computed by the ESA Flight Dynamics Team at ESOC. These ephemerides were computed using the motion models for Phobos and Deimos that were developed for the Russian Phobos project. These data have been provided by the Mars Express Flight Dynamics team as response to a request from the Mars Express High Resolution Stereo Camera (HRSC) Team to conduct Phobos and Deimos imagery data analysis. MEX_ASPERA_STRUCT_Vvv.BSP This SPK file contains fixed locations of several MEX ASPERA reference points. MEX_ROB_YYMMDD_yymmdd_vvv.BSP SPK files with ephemeris of Mars Express, centered in Mars, within the dates specified in the file name. These kernels are created by the Royal Observatorium of Belgium. They span data from YY-MM-DD to yy-mm-dd. vvv is the version number. NEW_NORCIA.BSP Ephemeris data for the ESA New Norcia Groundstation. ESTRACK_V01.BSP Ephemeris data for the ESA ESTRACK ground stations. Please note that the data in this kernel are low accuracy. ORHM_______________vvvvv.BSP Ephemeris data for Mars Express, centered in the Sun, for the Cruise Phase (from Jun. 2, 2003 to Dec. 22, 2003). ORMM__YYMM01000000_vvvvv.BSP Ephemeris actual data for Mars Express. YYMM is the month for which the file provides coverage, and vvvvv is the version number of the file (not relevant for the purpose of this dataset). Note: Files EARTHSTNS_FX_yymmdd.BSP and EARTHSTNS_ITRF93_yymmdd.BSP contain the same data. These files only differ in that the second one use the reference frame label 'ITRF93' instead of 'EARTH_FIXED'. 'EARTH_FIXED' alias must be map to either 'ITRF93' or 'IAU_EARTH' before using the file. For high accuracy work, EARTHSTNS_ITRF93_yymmdd.BSP is recommended (on the basis of ease of use). 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 each SPK file is provided in metadata included inside the comment area of the file. This information can be viewed using utility programs COMMNT and SPACIT included in the SPICE Toolkit. At least a basic knowledge of the SPICE system is needed in order to use this kernels. The SPICE toolkit provides versions in Fortran (SPICELIB), C (CSPICE) and IDL (icy), and the user can choose any one that suits him/her. The SPICELIB routine FURNSH, CSPICE function furnsh_c, and icy routine cspice_furnsh load a kernel file into the kernel pool as shown below. CALL FURNSH ( 'kernel_name' ) furnsh_c ( ''kernel_name'' ); cspice_furnsh, 'kernel_name' In the case when two or more files contain data overlapping in time for a given object, for binary kernels, the file loaded last takes precedence. If two (or more) text kernels assign value(s) using the '=' operator to identical keywords, the data value(s) associated with the last loaded occurrence of the keyword are used -all earlier values have been replaced with the last loaded value(s).