KPL/IK Standard Radiation Environment Monitor Instrument kernel =========================================================================== This instrument kernel (I-kernel) contains Rosetta Standard Radiation Environment Monitor (SREM) detector, and field-of-view parameters. Version and Date --------------------------------------------------------------------------- Version 1.0 -- March 26, 2018 -- Marc Costa, ESA/ESAC Initial release. References --------------------------------------------------------------------------- 1. Rosetta Frames Definition Kernel (FK), latest version. 2. ''Kernel Pool Required Reading'' 3. ``The Standard Radiation Environment Monitor'' http://srem.web.psi.ch/html/srem_home.shtml Accessed on March 26, 2018. Implementation Notes --------------------------------------------------------------------------- Applications that need SPICE I-kernel data must load the I-kernel file, normally during program initialization. Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the kernel pool. The application program may then obtain the value(s) for any IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL. Routine GETFOV may be used if the file contains instrument field-of-view (FOV) specification. See [2] for details. This file was created with, and can be updated with a text editor or word processor. Conventions for Specifying Data --------------------------------------------------------------------------- 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 Rosetta instrument ID code. The Star Tracker instrument IDs are defined in [1] as follows: Instrument name ID -------------------- ------- ROS_SREM_D12 -226601 ROS_SREM_D3 -226602 The remainder of the keyword is an underscore character followed by the unique name of the data item. For example, the boresight of the SREM Detector 1,2 (ROS_SREM_D12) is specified by INS-226601_BORESIGHT The upper bound on the length of all keywords is 32 characters. If a keyword is included in more than one file, or if the same keyword appears more than once within a single file, the last assignment supersedes any earlier assignments. Overview --------------------------------------------------------------------------- From [3]: SREM is a particle detector, developed for space applications. It measures high energy electrons and protons with a fair angular and spectral resolution and provides the host spacecraft with radiation information. SREM is the successor of the Radiation Environment Monitor REM. The Standard Radiation Environment Monitor is developed and manufactured by CONTRAVES SPACE AG in cooperation with the PAUL SCHERRER INSTITUT (PSI) under a development contract of the EUROPEAN SPACE AGENCY (ESA). SREM performs a wide range of radiation monitoring functions in orbit, and downloads the results via the host spacecraft telemetry to a user on ground. It is designed as a standard equipment compatible with all common spacecraft interfaces and mission constraints. The Standard Radiation Environment Monitor houses the following functional blocks: - Power supply with DC/DC converter with output voltages for the digital and the analog circuits, as well as for the detectors. - Three particle detectors with associated temperature sensors integrated in the detector housing. - Analog front end with low noise signal amplifiers and signal conditioning electronics. - Comparators with fifteen detection ranges. - Interface for remote total dose and temperature measurement sensors. - Signal processing electronics with host spacecraft interface for: 1) Data processing and storage of scientific data 2) Acquisition of housekeeping data and system health monitoring 3) Telemetry and telecommand interface with host spacecraft. What follows are the key performance features of SREM: ------------------------------------------------------------------------ Parameter Unit Value/Description ------------------------------------------------------------------------ Mass Kg 2.5 Dimensions mm 96 x 122 x 217 Power Cosumption W < 2 Floating bus voltage V 20 - 50 Sensors - Three precision particle detectors (measurement error < 1%) Internal total dose measurement Internal temperature measurement ------------------------------------------------------------------------ SREM operations: - Microprocessor, memory and data storage capacity for autonomous operation during several days. - Data downloading on request via host spacecraft telemetry. - Operational monitoring accessible from host spacecraft data handling system. The proton calibration is performed with protons up to 600 MeV, using an energy spectrum representative for the conditions in space. The calibration with electrons covers the range up to 5 MeV. The numerical simulations of the detector response, performed with the GEANT code, are verified based upon the results of the calibration and provide therefore a reliable database for the system input signal response characteristics. SREM data can be obtained from the following website: http://srem.web.psi.ch/cgibin/srem_data_sec.cgi Apparent FOV Layout --------------------------------------------------------------------------- This section provides a diagram illustrating the SREM D12 and SREM D3 detectors apparent FOVs layout in the corresponding reference frames. The SREM surface slit creates a circular field of view with half cone angle of 20 degrees. The following diagrams illustrate the above field of view in the instrument frame: Y X ins ins ^ / ^ / | / | / | / | / | / | / X | / o Y | / o ins |/ 20.0 ins |/ 20.0 x--------> o--------> |\ Z |\ Z | \ ins | \ ins | \ | \ | \ | \ | \ | \ | \ | \ Plane X = 0 Plane Y = 0 Please note that the FOV reference and cross angles are defined with half angle values. Mounting Alignment --------------------------------------------------------------------------- Refer to the latest version of the Rosetta Frames Definition Kernel (FK) [1] for the SREM reference frames definitions and mounting alignment information. FOV Definitions --------------------------------------------------------------------------- This section contains definitions for the SREM D12 and D3 FOVs. These definitions are provided in the format required by the SPICE (CSPICE) function GETFOV (getfov_c). \begindata INS-226601_FOV_FRAME = 'ROS_SREM_D12' INS-226601_FOV_SHAPE = 'CIRCLE' INS-226601_BORESIGHT = ( 0.0 0.0 1.0 ) INS-226601_FOV_CLASS_SPEC = 'ANGLES' INS-226601_FOV_REF_VECTOR = ( 1.0 0.0 0.0 ) INS-226601_FOV_REF_ANGLE = ( 20.0 ) INS-226601_FOV_ANGLE_UNITS = 'DEGREES' INS-226602_FOV_FRAME = 'ROS_SREM_D3' INS-226602_FOV_SHAPE = 'CIRCLE' INS-226602_BORESIGHT = ( 0.0 0.0 1.0 ) INS-226602_FOV_CLASS_SPEC = 'ANGLES' INS-226602_FOV_REF_VECTOR = ( 1.0 0.0 0.0 ) INS-226602_FOV_REF_ANGLE = ( 20.0 ) INS-226602_FOV_ANGLE_UNITS = 'DEGREES' \begintext Platform ID --------------------------------------------------------------------------- This number is the NAIF instrument ID of the platform on which the detectors are mounted. For both Star Trackers this platform is the orbiter. \begindata INS-226601_PLATFORM_ID = ( -226000 ) INS-226602_PLATFORM_ID = ( -226000 ) \begintext End of IK file.