KPL/IK MELACOM Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains Mars Express Lander Communications (MELACOM) field-of-view parameters. Version and Date --------------------------------------------------------------------------- Version 0.1 -- April 20, 2021 -- Ricardo Valles Blanco, ESAC/ESA Alfredo Escalante Lopez, ESAC/ESA Added proper documentation and comments' sections for Mars Express PDS3 V2.0 release. References ----------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``Frames Required Reading'' 3. Mars Express Spacecraft Frames Definition Kernel 4. An Interplanetary and Interagency Network - Lander Communications at Mars. SpaceOps 2008 Conference Paper. May 2008. DOI: 10.2514/6.2008-3536 Contact Information ---------------------------------------------------------------------------- If you have any questions regarding this file contact the ESA SPICE Service at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int, 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 SPICELIB routine FURNSH loads a kernel into the pool as 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' ) PYTHON: (SPICEYPY)* furnsh( frame_kernel_name ) In order for a program or routine to extract data from the pool, the SPICELIB routines GDPOOL, GIPOOL, and GCPOOL are used. See [2] for more details. This file was created and may be updated with a text editor or word processor. * SPICEYPY is a non-official, community developed Python wrapper for the NAIF SPICE toolkit. Its development is managed on Github. It is available at: https://github.com/AndrewAnnex/SpiceyPy Naming Conventions ----------------------------------------------------------------------------- Data items are specified using ''keyword=value'' assignments [1]. All keywords referencing values in this I-kernel start with the characters `INS' followed by the NAIF MEX instrument ID code, constructed using the spacecraft ID number (-41) followed by the NAIF three digit ID number for one of the MELACOM data item. These IDs are as follows Instrument name ID ------------------------ ------ MEX_MELACOM_35 -41037 MEX_MELACOM_70 -41038 MEX_MELACOM_90 -41039 The remainder of the name is an underscore character followed by the unique name of the data item. For example, the MEX_MELACOM_35 boresight direction in the frame MEX_MELACOM_1 frame (see [2]) is specified by: INS-41037_BORESIGHT The upper bound on the length of the name of any data item identifier is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. Overview ----------------------------------------------------------------------------- From [4]: The Mars Express Lander Communications subsystem (MELACOM) was initially designed as a relay for communications with the BEAGLE-2 lander. The failure of the landing over Christmas 2003 made its attempted use with BEAGLE-2 from January to February 2004 unsuccessful. However, intrinsic to the design was the capability for crosssupport with other landers via the implementation of version 2 of the draft Proximity-1 protocol, CCSDS 211.0-R-2, which was designed to ensure reliable data transfer between remote autonomous communication nodes operating in close proximity. Reliability of the communications capability is ensured as MELACOM is a fully-redundant unit. To enable support of future communications protocols, it is possible to reprogram the MELACOM relay software and thus remain compatible with future landed assets on Mars, within the limits of the flight hardware. The MELACOM transponder: Apart from its X-Band and S-Band transponders, used together with the High Gain Antenna for the long distances communications with the Earth and for Radio Science (Spacecraft to Earth distance reaching 2.7 A.U. = 400 Millions of km), Mars-Express embeds a UHF transponder "MELACOM" (401 - 437 MHz) and 2 patch antennas to communicate at closer distances of a few hundred km, with any landed asset on Mars surface supporting the CCSDS Proximity-1 protocol. It was designed to relay at least 10 Mbits of information per day. The unit can operate in 3 different modes: 1. A "Canister" mode, in which the receiver samples the incoming signal even when very weak and with or without modulation. This open-loop recording needs ground post-processing in order to extract together with a timescale, the frequencies that have been detected in the receiver channel. This powerful scanner can also be used to provide onboard UHF interferences characterization. 2. A mode allowing sampling of Doppler measurements on the incoming signal, once a RF lock is achieved on the incoming carrier. 3. A mode dedicated to communications with landers or rovers on Mars surface, allowing to send commands to them (Forward link) and to fetch telemetry data from them (Return Link). In order to do this, MELACOM implements Red book 3 of the Proximity-1 protocol (CCSDS 211.0-R-3). Mounting Alignment ----------------------------------------------------------------------------- Refer to the latest version of the Mars Express Frames Definition Kernel (FK) [3] for the MELACOM reference frame definitions and mounting alignment information. FOV Definitions --------------------------------------------------------------------------- The MELACOM antennas have a wide 180 degrees pattern centered at the boresight (+Z axis). These antennas have a gain of 3dB inside the 70 degrees cone centered in the boresight (+/-35 degrees around +Z). Considering this there are two main FOVs defined in this IK file for specifying this 180 degrees FOV (MEX_MELACOM_90) and the 70 degrees FOV (MEX_MELACOM_35). There is also specified another FOV of 140 degrees (+/-70 degrees around +Z) (MEX_MELACOM_70) just intended for science opportunity analysis purposes. \begindata INS-41037_FOV_CLASS_SPEC = 'ANGLES' INS-41037_FOV_SHAPE = 'CIRCLE' INS-41037_FOV_FRAME = 'MEX_MELACOM_1' INS-41037_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-41037_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-41037_FOV_REF_ANGLE = ( 35.0 ) INS-41037_FOV_ANGLE_UNITS = ( 'DEGREES' ) INS-41038_FOV_CLASS_SPEC = 'ANGLES' INS-41038_FOV_SHAPE = 'CIRCLE' INS-41038_FOV_FRAME = 'MEX_MELACOM_1' INS-41038_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-41038_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-41038_FOV_REF_ANGLE = ( 70.0 ) INS-41038_FOV_ANGLE_UNITS = ( 'DEGREES' ) INS-41039_FOV_CLASS_SPEC = 'ANGLES' INS-41039_FOV_SHAPE = 'CIRCLE' INS-41039_FOV_FRAME = 'MEX_MELACOM_1' INS-41039_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-41039_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-41039_FOV_REF_ANGLE = ( 90.0 ) INS-41039_FOV_ANGLE_UNITS = ( 'DEGREES' ) \begintext NAIF ID Codes Definitions ============================================================================== This section contains name to NAIF ID mappings for Mars Express Lander Communications system (MELACOM). 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. This table presents the instrument and sensor names and IDs: Name ID Synonyms ------------------------- ----------- ----------------------- MEX_MELACOM_35 -41037 MEX_MELACOM_70 -41038 MEX_MELACOM_90 -41039 The mappings summarized in this table are implemented by the keywords below. \begindata NAIF_BODY_NAME += ( 'MEX_MELACOM_35' ) NAIF_BODY_CODE += ( -41037 ) NAIF_BODY_NAME += ( 'MEX_MELACOM_70' ) NAIF_BODY_CODE += ( -41038 ) NAIF_BODY_NAME += ( 'MEX_MELACOM_90' ) NAIF_BODY_CODE += ( -41039 ) \begintext End of IK file.