IMAGE Housekeeping UDF files. The Housekeeping UDF data is taken from two RAD-6000 processors: the Central Interface Data Processor (CIDP) which provides acquisition, compression, storage, and telemetry formatting of science data from all imagers; health and status monitoring; and interface with the Spacecraft/System Control Unit (SCU). For more details on reading UDF files see the document "Reading_UDF_files.txt" From the CIDP and SC UDF files the following CDF formatted files were derived for specific housekeeping categories: IM_HK_ADS: Image Attitude Determination System Housekeeping IM_HK_AST: Image Autonomous Star Tracker Housekeeping IM_HK_COM: Image Communication Systems Housekeeping IM_HK_FSW: Image Flight Software Housekeeping IM_HK_PWR: Image Power Systems Housekeeping IM_HK_TML: Image Thermal Housekeeping These files can be browsed using the CDAWeb service. Relevant website Further details on the functions provided by the CIDP and the SCU. (from Section 3.4 in Gibson, W.C., et al.,"The IMAGE Observatory", Space Science Reviews, 91,15-50,2000.) The CIDP provides the following major functions for the Observatory: (1) Instrument data acquisition, processing, and compression. (2) Stored command processing. (3) Command receipt (from the SCU), processing, storage (if a delayed command), and transfer to the instruments. (4) Time/attitude synchronization with the spacecraftÕs Attitude Determination and Control system for generation of the nadir and sun pulse signals sent to the instruments. (5) Deckplate thermal control. (6) Additional EEPROM storage for instrument software or tables. (7) Power switching and current limiting. The SCU provides the following major functions for the Observatory: (1) Ground command receipt, processing, storage (for delayed command execution) and relay to the CIDP. (2) Telemetry data formatting and downlink (3) Spacecraft attitude determination and control. (4) Spacecraft thermal control. (5) Spacecraft power management. (6) Spacecraft housekeeping data acquisition, formatting, and storage. (7) Management of the Mass Memory Module. (8) Management of the engineering and high speed telemetry downlink. (9) Safe/hold management of the Observatory. The key design features of the IMAGE spacecraft (from the SWRI IMAGE web site) * Mechanical Subsystem Aluminum honeycomb side panels (8), forward and aft panels, payload deck, and interior shear walls; two central load-bearing aluminum cylinders (forward and aft) * Mass 494 kg * Dimensions Width = 2.25 m (7.4 ft) Height = 1.52 m (4.99 ft) * Thermal Subsystem Heat pipes in payload deck connected to radiators on spacecraft side panels; MLI blankets; thermostat- and CIDP/PDU-controlled electrical resistance heaters for payload and spacecraft operations and survival * Command & Data Handling Subsystem System Control Unit (SCU) consisting of RAD6000 flight computer plus modules for I/O, mass memory, command & telemetry, communications & memory, and power suppy; VME backplane; 4.096 Gbits DRAM in mass memory module; Mil-Std-1553B interfaces to other observatory systems * Communications Subsystem S-band transponder; 1 medium-gain helix antenna; 2 low-gain omni-directional antennas; uplink data rate: 2 kbps; downlink data rate: 44 kbps (real-time mode); 2.28 Mbps (stored data playback mode) * Attitude Determination & Control Subsystem Spin-stabilized; closed-loop spin-rate control * Sensors Adcole 44690 sun sensor; Lockheed Martin ATC AST-201R autonomous star tracker; MEDA TAM-2A 3-axis magnetometer * Actuator 1 Ithaco magnetic torque rod * Electrical Power Subsystem Direct energy transfer; microprocessor-controlled power distribution unit (PDU) performs power distribution and battery charge control functions; Mil-Std-1553B interface with SCU * Solar Arrays Body-mounted dual-junction gallium-arsenide solar cell arrays * Battery 21 amp-hour Super NiCd battery; operating range: 22-34 Vdc