On-board Computer
10
H|0|mms|MMS|133|135|
H|0|ariane|launch vehicle|399|412|
H|0|hga|high-gain antenna|436|452|
H|0|solar|solar array|509|519|
G|0|ephemeris|ephemeris|464|472|
G|0|nadir|nadir|368|372|
G|0|safe|safe-hold mode|778|791|
G|0|telemetry|telemetry|246|254|
A|2||on-board computer|9|25|170,137,262,137,
H|0|ops|flight team|846|856|
    The on-board computer responsible for controlling TOPEX/Poseidon is a NASA Standard Spacecraft Computer inherited from previous MMS-based missions. 
    The computer controls the distribution of commands to the satellite and the delivery of telemetry to the ground. It also performs attitude control computations that keep the satellite accurately pointed at the nadir. Other functions include launch vehicle separation detection, high-gain antenna pointing, ephemeris computation, power monitoring, and solar array pointing. 
    The on-board computer also contains fault detection and correction software that identifies and immediately responds to system failures. The computer has the ability to isolate or bypass attitude sensors, and will order the spacecraft into a safe-hold mode if the detected problem requires intervention by the flight team.
