KPL/FK Trace Gas Orbiter (TGO) Spacecraft Frames Kernel =============================================================================== This frame kernel contains complete set of frame definitions for the ExoMars-16 Trace Gas Orbiter Spacecraft (TGO) including definitions for the TGO structures and TGO science instrument frames. This kernel also contains NAIF ID/name mapping for the TGO instruments. Version and Date ------------------------------------------------------------------------ Version 0.2 -- March 11, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary Version. Added CaSSIS frames. Version 0.1 -- January 26, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary Version. Added TGO_SPACECRAFT frame for its use with test CK kernel. Version 0.0 -- December 17, 2015 -- Jorge Diaz del Rio, ODC Space Preliminary Version. Only TGO Name to NAIF ID mappings for their use with test SPK kernel. References ------------------------------------------------------------------------ 1. ``Frames Required Reading'', NAIF 2. ``Kernel Pool Required Reading'', NAIF 3. ``C-Kernel Required Reading'', NAIF 4. ``Exo-Mars: Science Operations Centre – Flight Dynamics – Pointing Timeline-ICD,'' EXM-GS-ICD-ESC-50003, Issue 1.4, 15 December 2015 5. ``CaSSIS Rotation Axis Determination Report,'' EXM-CA-TRE-UBE-00112 Issue 0.7, 1 March 2016 6. ``The Color and Stereo Surface Imaging System (CaSSIS) for ESA’s Trace Gas Orbiter.'' Eighth International Conference on Mars (2014) N. Thomas et al. 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. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name; ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB This file was created and may be updated with a text editor or word processor. TGO NAIF ID Codes -- Summary Section ------------------------------------------------------------------------ The following names and NAIF ID codes are assigned to the TGO spacecraft, its structures and science instruments (the keywords implementing these definitions are located in the section "TGO NAIF ID Codes -- Definition Section" at the end of this file): TGO Spacecraft and Spacecraft Structures names/IDs: TGO -143 (synonym: EXOMARS-ORBITER) CaSSIS names/IDs: TGO Frames ------------------------------------------------------------------------ The following TGO frames are defined in this kernel file: Name Relative to Type NAIF ID ====================== =================== ============ ======= TGO Spacecraft and Spacecraft Structures frames: ------------------------------------------------ TGO_SPACECRAFT J2000 CK -143000 ACS frames: ----------- CaSSIS frames: -------------- TGO_CASSIS_CRU TGO_SPACECRAFT FIXED -143400 TGO_CASSIS_TEL TGO_CASSIS_CRU CK -143410 TGO_CASSIS_FSA TGO_CASSIS_TEL FIXED -143420 FREND frames: ------------- NOMAD frames: ------------- TGO Spacecraft and Spacecraft Structures Frames ------------------------------------------------------------------------ This section of the file contains the definitions of the spacecraft and spacecraft structures frames. TGO Spacecraft Frames -------------------------------------- According to [4] the TGO spacecraft reference frame -- TGO_SPACECRAFT is defined as follows: - +X axis is perpendicular to the launch vehicle interface plane and points towards the Schiaparelli Entry, Descent and Landing Demonstrator Module (EDM) attachment point; - -Y axis is perpendicular to the payload science deck and points towards the payload side; representing the reference spacecraft line of sight towards Mars during science operations; - +Z axis completes the right-handed frame. - the origin of this frame is the launch vehicle interface point. These diagrams illustrate the TGO_SPACECRAFT frame: -X s/c side (HGA side) view: ---------------------------- ^ | toward Mars | Science Deck ._____________. .__ _______________. | | .______________ ___. | \ \ \ | | / \ \ | | / / \ | | / / / | | \ \ `. | | .' \ \ | | / / | o| |o | / / | | \ \ .' | | `. \ \ | | / / / | | \ / / | .__\ \_______________/ | +Xsc | \_______________\ \__. +Z Solar Array <--------x______. -Z Solar Array +Zsc .__|__. .' | `. / | \ . `. v +Ysc . +Xsc is into | `o' | the page . | . \ | / `. .' HGA ` --- ' -Y s/c side (science deck side) view: ------------------------------------- _____ / \ EDM |+Xsc | .______^______. | | | | | | +Zsc | | | o==/ /==================o<-------x |>o==================/ /==o +Z Solar Array | +Ysc | -Z Solar Array | | ._____________. HGA .' `. /___________\ `.|.' +Ysc is into the page. Since the orientation of the TGO_SPACECRAFT frame is computed on-board, sent down in telemetry, and stored in the s/c CK files, it is defined as a CK-based frame. These sets of keywords define the TGO_SPACECRAFT frame: \begindata FRAME_TGO_SPACECRAFT = -143000 FRAME_-143000_NAME = 'TGO_SPACECRAFT' FRAME_-143000_CLASS = 3 FRAME_-143000_CLASS_ID = -143000 FRAME_-143000_CENTER = -143 CK_-143000_SCLK = -143 CK_-143000_SPK = -143 OBJECT_-143_FRAME = 'TGO_SPACECRAFT' \begintext CaSSIS Frames ------------------------------------------------------------------------ This section of the file contains the definitions of the Colour and Stereo Surface Imaging System (CaSSIS) instrument frames. CaSSIS Frame Tree ~~~~~~~~~~~~~~~~~ The diagram below shows the CaSSIS frame hierarchy. "J2000" INERTIAL +-----------------------------------------------------+ | | | |<-pck | |<-pck | | | V | V "IAU_MARS" | "IAU_EARTH" MARS BODY-FIXED |<-ck EARTH BODY-FIXED --------------- | ---------------- V "TGO_SPACECRAFT" ---------------- | |<-fixed | V "TGO_CASSIS_CRU" ---------------- | |<-ck | V "TGO_CASSIS_TEL" ---------------- | |<-fixed | "TGO_CASSIS_FSA" ---------------- CaSSIS Camera Rotation Unit frame ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The CaSSIS Camera Rotation Unit (CRU) is rigidly mounted on the spacecraft science deck. Therefore, the frame associated with it -- the CaSSIS CRU frame, TGO_CASSIS_CRU -- is specified as a fixed offset frame relative with its orientation given relative to the JUICE_SPACECRAFT frame. The CaSSIS CRU frame is defined by the camera rotation unit design and its mounting on the spacecraft as follows (from [5]): - +Y axis is along the nominal CaSSIS CRU rotation axis, and it is nominally co-aligned with the spacecraft -Y axis - +Z axis is co-aligned with the +Z spacecraft axis; - +X axis completes the right-handed frame; - the origin of the frame is located at the center of the CaSSIS reference hole (RH) at the instrument's interface plane, i.e. the unit mounting plane to the spacecraft. Any misalignment between the nominal and actual CaSSIS CRU rotation axis measured pre-launch or during in-flight calibration should be incorporated into the definition of this frame. This diagram illustrates nominal TGO_CASSIS_CRU frame with respect to the spacecraft frame. -X s/c side (HGA side) view: ---------------------------- ^ | toward Mars | ^ +Ycru | Science deck | .____________|. .__ _______________. | <--------o| .______________ ___. | \ \ \ | +Zcru +Xcru / \ \ | | / / \ | | / / / | | \ \ `. | | .' \ \ | | / / | o| |o | / / | | \ \ .' | | `. \ \ | | / / / | | \ / / | .__\ \_______________/ | +Xsc | \_______________\ \__. +Z Solar Array <--------x______. -Z Solar Array +Zsc .__|__. .' | `. / | \ . `. v +Ysc . +Xsc is into | `o' | the page and +Xcru . | . is out of the page \ | / `. .' HGA ` --- ' +Z CaSSIS Rotation Unit side view: ---------------------------------- +Xsc ^ .--. . | |. | . ' / | | | ______________ . ' / | /---. .-| ___ ____ ' \ , <-------o +Zsc /' | | | / \ / '. '.\ / +Ysc / | | | || || ' ' .' .-----. | | | || || '. '. /___, ,| | | || || '. '. / /+Zcru |= | | \___/ \_____________/ '. +Ycru / \ | o---------------------------------------------> / '| | | |.| / | | rotation axis | | | / | | | '-'_._____| |_______' '________' | | / | | | | | .--- .------. '-' / '--|-| | | , -- . '. \ \_.-. / | | | | | '. '. \ | | /________________|_| '-'_ | '. . | | | || |.-|.| \ \______________. | | || || ||| \ .-------------------------'-' .-----''-------------''-|''--------. \| | | | '-----------------------|----------' | v +Xcru +Zsc and +Zcru are out of the page Nominally, a single rotation of 180 degrees about +Z axis is required to co-align the TGO_CASSIS_CRU and the TGO_SPACECRAFT frames. Since the SPICE frames subsystem calls for specifying the reverse transformation--going from the instrument or structure frame to the base frame--as compared to the description given above, the order of rotations assigned to the TKFRAME_*_AXES keyword is also reversed compared to the above text, and the signs associated with the rotation angles assigned to the TKFRAME_*_ANGLES keyword are the opposite from what is written in the above text. \begindata FRAME_TGO_CASSIS_CRU = -143400 FRAME_-143400_NAME = 'TGO_CASSIS_CRU' FRAME_-143400_CLASS = 4 FRAME_-143400_CLASS_ID = -143400 FRAME_-143400_CENTER = -143 TKFRAME_-143400_RELATIVE = 'TGO_SPACECRAFT' TKFRAME_-143400_SPEC = 'ANGLES' TKFRAME_-143400_UNITS = 'DEGREES' TKFRAME_-143400_AXES = ( 1, 2, 3 ) TKFRAME_-143400_ANGLES = ( 0.0, 0.0, 180.0 ) \begintext CaSSIS Telescope frame ~~~~~~~~~~~~~~~~~~~~~~ The CaSSIS telescope rotates counterclockwise around the +Y CaSSIS Camera Rotation Unit by an angle commanded from ground which ranges from 0 degrees in the homing position to 360.0 degrees at the end of the range. The CaSSIS Telescope frame is defined by the camera rotation unit design as follows (from [5]): - +Y axis is along the nominal CaSSIS CRU rotation axis, and it is 'zero' position is co-aligned with the TGO_CASSIS_CRU +Y axis - +Z axis is co-aligned with the TGO_CASSIS_CRU +Z axis, when the motor is in its 'zero' position; - +X axis completes the right-handed frame; - the origin of the frame is located at the focal point of the CaSSIS telescope. This diagram illustrates the TGO_CASSIS_TEL frame with respect to the TGO_CASSIS_CRU frame for different motor rotations. +Y CaSSIS Camera Rotation Unit view: ------------------------------------ ^ +Xtel ^ +Xcru 0 deg | | position | | ....|.... | .' | `. | +Zcru .' | `. o---------> ' | ' +Ycru . | . . | . 90 deg ---- . o--------------> +Ztel position . +Ytel . . . .-'. .'-. ' . . ' 120 deg `. .' 240 deg position ` ......... ' position | | 180 deg +Ysc position x--------> | +Zsc | +Ytel and +Ycru are into | the page; +Ysc is out of | the page. v +Xsc For an arbitrary scanner angle, the TGO_CASSIS_TEL frame is rotated by this angle about the +Y axis with respect to the TGO_CASSIS_CRU frame. This set of keywords define the CaSSIS Telescope frame: \begindata FRAME_TGO_CASSIS_TEL = -143410 FRAME_-143410_NAME = 'TGO_CASSIS_TEL' FRAME_-143410_CLASS = 3 FRAME_-143410_CLASS_ID = -143410 FRAME_-143410_CENTER = -143 CK_-143410_SCLK = -143 CK_-143410_SPK = -143 \begintext \begintext CaSSIS Filter Strip Assembly (FSA) frame: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The CaSSIS Camera Rotation Unit is designed to support quasi-simultaneous stereo imaging by aligning the image columns to the orbital track (see [6]). Above the detector surface, a filter strip is placed in order providing images in 4 different wavelength bands. The CaSSIS Filter Strip Assembly -- TGO_CASSIS_FSA frame is defined based on the telescope pointing axis and the detector surface orientation as follows: - +Z axis points along the telescope optical boresight; - +X axis is aligned to the detector rows; - +Y axis is aligned to the detector columns; - the origin of the frame is located at the focal point of the CaSSIS telescope. The CaSSIS telescope optical boresight nominally points 10 degrees off from the CaSSIS rotation axis -- TGO_CASSIS_TEL +Y axis, towards the +Z TGO_CASSIS_TEL axis. This diagram illustrates the TGO_CASSIS_FSA frame with respect to the TGO_CASSIS_TEL frame. +Z CaSSIS Rotation Unit side view: ---------------------------------- ^ +Ytel (rotation axis) ^ | towards Mars \ | +Zfsa \ | .---------. \ .----|-. .---------| \ '----|-'.' .-. | .. \ / | .' | | \ `. \ .. |-. .' .' | \ `. / \/ | | | | .' | \ `/ /\ | | | | .' . | \ / / \| | | |.' .' | | \/ / \ | | .' | | / / |\ |.' | | | | | | \| . | | | | | | .o +Yfsa | | | | .' |' | | | | | \___.' | | | | | | _.'_ | | | | | | .' \ | | | | | | .' | |----' '-----' '__ +Xfsa .' | | |---. .' +Ztel and +Yfsa <.'| | | | | .' are out of the page | | | | |.________' | \____/ |---'|'------' '____________|____' '-----------|---' +Xtel o--------------------------> +Ztel Nominally, the off-pointing from the CaSSIS Filter Strip Assembly boresight and the CaSSIS Telescope rotation axis is 10 degrees towards the -X CaSSIS Telescope axis. During the geometrical measurements performed before the integration on the spacecraft, the angle between the rotation axis and the instrument optical boresight at 5 different positions (see p.34 of [6]) was: alpha = 9.89 +/- 0.1 degrees Therefore, in order to transform the CaSSIS Telescope frame into the CaSSIS Filter Strip Assembly frame, first an initial rotation of 90 degrees about the +X axis is required, followed by a 170.11 degrees rotation about the resulting +Y axis. Since the SPICE frames subsystem calls for specifying the reverse transformation--going from the instrument or structure frame to the base frame--as compared to the description given above, the order of rotations assigned to the TKFRAME_*_AXES keyword is also reversed compared to the above text, and the signs associated with the rotation angles assigned to the TKFRAME_*_ANGLES keyword are the opposite from what is written in the above text. \begindata FRAME_TGO_CASSIS_FSA = -143420 FRAME_-143420_NAME = 'TGO_CASSIS_FSA' FRAME_-143420_CLASS = 4 FRAME_-143420_CLASS_ID = -143420 FRAME_-143420_CENTER = -143 TKFRAME_-143420_RELATIVE = 'TGO_CASSIS_TEL' TKFRAME_-143420_SPEC = 'ANGLES' TKFRAME_-143420_UNITS = 'DEGREES' TKFRAME_-143420_AXES = ( 2, 1, 2 ) TKFRAME_-143420_ANGLES = ( 0.0, -90.00, 170.11 ) \begintext TGO NAIF ID Codes -- Definitions =============================================================================== This section contains name to NAIF ID mappings for the ExoMars-16 mission. Once the contents of this file is loaded into the KERNEL POOL, these mappings become available within SPICE, making it possible to use names instead of ID code in the high level SPICE routine calls. Name ID Synonyms --------------------- ------- ----------------------- Spacecraft: ----------- TGO -143 EXOMARS-ORBITER TGO_SPACECRAFT -143000 The mappings summarized in this table are implemented by the keywords below. \begindata NAIF_BODY_NAME += ( 'TGO' ) NAIF_BODY_CODE += ( -143 ) NAIF_BODY_NAME += ( 'EXOMARS-ORBITER' ) NAIF_BODY_CODE += ( -143 ) NAIF_BODY_NAME += ( 'TGO_SPACECRAFT' ) NAIF_BODY_CODE += ( -143000 ) \begintext