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, one or more of Frame Definitions Kernel (FK), Planetary Constants Kernel (PcK), and C-Kernel (CK) files may also be 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 set. 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 ESAC SPICE Service. The naming convention for these kernels is the same used in the Ephemeris products used to create them; their file name 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 little-endian (LTL-IEEE) binary files. Mars Express SPK-Kernels Contained in this Data Set =================================================== The following SPK-kernels are provided in this data set: DE405.BSP SPICE Kernel (SPK) that contains ephemeris data for planet barycenters, and for the sun, earth and moon mass centers. Spans the entire Mars Express mission. EARTHSTNS_ITRF93_yymmdd.BSP SPICE Kernel (SPK) that contains ephemeris data for NASA DSN stations relative to the terrestrial reference frame label 'ITR93'. This file was released on yymmdd. MAR097_030101_300101_V0001.BSP SPICE Kernel (SPK) that contains JPL ephemeris data for Phobos, Deimos, Mars and Earth. Spans the entire Mars Express mission. MEX_ASPERA_STRUCT_Vvv.BSP SPICE Kernel (SPK) that contains relative locations of the ASPERA structures with respect to the spacecraft bus and each other. This SPK spans the entire Mars Express mission. MEX_PFS_ROIS_Vvv.BSP SPICE Kernel (SPK) that contains position information for Mars Express Regions of Interest for the PFS instrument. MEX_RELAY_LOCATIONS_Vvv.BSP SPICE Kernel (SPK) that contains position information for selected landers and rovers for which Mars Express is a relay for. MEX_ROB_YYMMDD_yymmdd_vvv.BSP SPICE Kernel (SPK) that contains high precision ephemeris for Mars Express (MEX), created by the Royal Observatory of Belgium. The kernels cover MEX position from YYMMDD to yymmdd; vvv is the version number. MEX_STRUCT_Vvv.BSP SPICE Kernel (SPK) that contains the location of various Mars-Express instruments and structures. ESTRACK_Vvv.BSP SPICE Kernel (SPK) that contains the position for each of the ESA ESTRACK ground stations relative to the center of the Earth. In the interest of flexibility, in this file the reference frame is labeled with the alias 'EARTH_FIXED'. Any application using this file must map the alias 'EARTH_FIXED' to either 'ITRF93' or 'IAU_EARTH'. EARTHSTNS_RU_YYYYMMDD.BSP SPICE Kernel (SPK) that contains the position for each of the Russian ground stations relative to the center of the Earth. C2013A1_S105_MERGED.BSP SPICE Kernel (SPK) that contains ephemeris data for Comet Siding Spring. Spans the entire Mars Express mission. ORHM_______________vvvvv.BSP SPICE Kernel (SPK) that contains ephemeris data for Mars Express, centered in the Sun, for the Cruise Phase (from Jun. 2, 2003 to Dec. 22, 2003). ORMM_T19_YYMM01000000_vvvvv.BSP SPICE Kernel (SPK) that contains 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 data set). 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. 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 'ITR93' instead of 'EARTH_FIXED'. 'EARTH_FIXED' alias must be map to either 'ITR93' or 'IAU_EARTH' before using the file. For high accuracy work, EARTHSTNS_ITRF93_yymmdd.BSP is recommended (on the basis of ease of use). 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 these kernels. The SPICE Toolkit provides versions in Fortran (SPICELIB), C (CSPICE), IDL (Icy), Matlab (Mice), and Java (JNISpice) and the user can choose any one that suits him/her. The SPICE routine FURNSH can be used to load a kernel file into a SPICE-based application to make kernel data usable with SPICE APIs. In the case when two or more binary SPK files contain data overlapping in time for a given object the file loaded last takes precedence. Please note that SPKs that contain 'T19' in their filename indicate that they are Type 19 SPKs as opposed to type 18. T19 SPKs contain the same data as their non-T19 counterparts but they have precedence due to computational efficiency (although they require Toolkit version N0065 or higher).