KPL/FK Frame (FK) SPICE kernel file for TGO science operations frames =============================================================================== This frames kernel defines a number of frames used by the TGO science operations centre to perform mission analysis and attitude dependent science opportunity identification. These frames can be used stand-alone, i.e. referring directly to them and assuming they correspond to the TGO spacecraft reference frame, or in combination with the TGO spacecraft frames. The latter will allow the user to use the existing alignments and instrument frame definitions to perform instrument specific mission analysis and attitude dependent science opportunity identification. Please refer to the section ``Using these frames'' for further details. Version and Date ------------------------------------------------------------------------------- Version 0.2 -- August 2, 2016 -- Marc Costa Sitja, ESAC/ESA Removed ``TGO Mars Nadir orbit-aligned pointing'' frame definition for there is no use case in ExoMars 2016 for it. Corrected minor typos. Version 0.1 -- June 6, 2016 -- Jorge Diaz del Rio, ODC Space Update comments to reflect new file naming conventions for ExoMars 2016 frame kernels. Version 0.0 -- May 22, 2016 -- Jorge Diaz del Rio, ODC Space Initial version. References ------------------------------------------------------------------------------- [1] "Frames Required Reading" [2] "Kernel Pool Required Reading" [3] ``Science Operations Centre - Flight Dynamics - Pointing Timeline-ICD'' EXM-GS-ICD-ESC-50003 Issue 1.4, 15-12-2015 Contact Information ------------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESAC: Marc Costa Sitja (+34) 91-8131-457 mcosta@sciops.esa.int, esa_spice@sciops.esa.int or SPICE support at IKI: Anton Ledkov +7 (495) 333-12-66 aledkov@rssi.ru or NAIF at JPL: Boris Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov 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 the data items with their names in a data structure called the "kernel pool". The routine that loads a kernel into the pool is shown below: FORTRAN: (SPICELIB) CALL FURNSH ( frame_kernel_name ) C: (CSPICE) furnsh_c ( frame_kernel_name ); IDL: (ICY) cspice_furnsh, frame_kernel_name MATLAB: (MICE) cspice_furnsh ( 'frame_kernel_name' ) This file was created and may be updated with a text editor or word processor. TGO Science Operations frame names and NAIF ID Codes ------------------------------------------------------------------------------- The following frame is defined in this kernel file: SPICE Frame Name Long-name ------------------------ --------------------------------------------- TGO_MARS_NPO TGO Mars Nadir power-optimized pointing These frame has the following centers, frame class and NAIF ID: SPICE Frame Name Center Class NAIF ID ------------------------ --------------------- ------- --------- TGO_MARS_NPO TGO DYNAMIC -143910 The keywords implementing that frame definitions is located in the "TGO Science Operations Frame Definitions" section. General Notes About This File ------------------------------------------------------------------------------- About Required Data: -------------------- All the dynamic frames defined in this file require at least one of the following kernel types to be loaded prior to their evaluation, normally during program initialization: - Planetary and Satellite ephemeris data (SPK), i.e. de432, de405, etc; - Spacecraft ephemeris data (SPK); Note that loading different kernels will lead to different orientations of the same frame at a given epoch, providing different results from each other, in terms of state vectors referred to these frames. Using these frames ------------------ These frames have been implemented to define the different pointing profiles for the TGO spacecraft. These pointing profiles can be used in two different ways: [1] ``As is'' for analysis of offsets between the spacecraft attitude defined in the corresponding CK and a given pointing profile. Loading this kernel in combination with any TGO CK will allow the user to perform this comparison between the TGO_SPACECRAFT frame and any of the different frames defined within this kernel. [2] In combination with the TGO Frames kernel, to define a default pointing profile for the whole duration of the mission together with the spacecraft and instrument frames defined in the TGO FK. In this way, instrument-specific mission analysis activities, for which a particular pointing profile and knowledge of the instruments is required, can be conducted without the need for a spacecraft CK. In order to define such default pointing profile, the latest TGO frames kernel and this file shall be loaded before the selected ``TGO spacecraft frame overwrite'' frame kernel. As an example, imagine that the desired default pointing profile is "Nadir power optimized with respect to Mars", then the furnish (metakernel) file should contain the following sequence of frames kernels, in the following order: ... $DATA/fk/em16_tgo_v00.tf $DATA/fk/em16_tgo_ops_v00.tf $DATA/fk/em16_tgo_sc_mars_npo_v01.tf ... (*) the example presents version 0.0 of the ExoMars-2016 frames and TGO Science Operations frames kernels. Newer versions of these files will produce the same results. By loading the ``em16_tgo_sc_mars_npo_vNN.tf'' frames kernel last, the spacecraft frame TGO_SPACECRAFT, which is defined as a CK-based frame in the ``TGO frames kernel'', will be overwritten as a type-4 fixed offset frame, mapping the TGO_SPACECRAFT frame to the TGO_MARS_NPO frame defined in the ``TGO Science Operations Frames Kernel'' (this) file. TGO Science Operations Frame Definitions ------------------------------------------------------------------------------- This section contains the definition of the TGO science operations frames. TGO Mars Nadir power-optimized pointing frame (TGO_MARS_NPO) ------------------------------------------------------------------------ Definition: ----------- The TGO Mars Nadir power-optimized pointing frame is defined as follows (from [3]): - -Y axis is the primary vector and points from TGO to the center of Mars (Nadir direction); - -X axis is the secondary vector and is the orthogonal component to the -Y axis of the Sun position relative to TGO; - +Z axis completes the right-handed system; - the original of this frame is the spacecraft's center of mass. All vectors are geometric: no corrections are used. Required Data: -------------- This frame is defined as a two-vector frame. Both the primary and the secondary vector are defined as an 'observer-target position' vectors, therefore, the ephemeris data required to compute both the TGO-Mars position and the TGO-Sun position in J2000 frame have to be loaded before using this frame. Remarks: -------- Since the primary and secondary vectors of this frame are defined based on the TGO-Mars position and TGO-Sun position vectors, the usage of different ephemerides to compute these vectors may lead to different frame orientation at given time. \begindata FRAME_TGO_MARS_NPO = -143910 FRAME_-143910_NAME = 'TGO_MARS_NPO' FRAME_-143910_CLASS = 5 FRAME_-143910_CLASS_ID = -143910 FRAME_-143910_CENTER = -143 FRAME_-143910_RELATIVE = 'J2000' FRAME_-143910_DEF_STYLE = 'PARAMETERIZED' FRAME_-143910_FAMILY = 'TWO-VECTOR' FRAME_-143910_PRI_AXIS = '-Y' FRAME_-143910_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION' FRAME_-143910_PRI_OBSERVER = 'TGO' FRAME_-143910_PRI_TARGET = 'MARS' FRAME_-143910_PRI_ABCORR = 'NONE' FRAME_-143910_SEC_AXIS = '-X' FRAME_-143910_SEC_VECTOR_DEF = 'OBSERVER_TARGET_POSITION' FRAME_-143910_SEC_OBSERVER = 'TGO' FRAME_-143910_SEC_TARGET = 'SUN' FRAME_-143910_SEC_ABCORR = 'NONE' FRAME_-143910_SEC_FRAME = 'J2000' \begintext