Mars Global Surveyor Spacecraft Overview
The
spacecraft will be three-axis stabilized with no scan platform. The main 596 N thruster
wil use hydrazine and N2O4 propellant. Control will be through 12 4.45 N hydrazine
thrusters, mounted in four groups of three (two aft facing and one roll control thruster).
The initial propellant load will be 216.5 kg of hydrazine and 144 kg of N2O4. Four solar
array panels (2 GaAs, 2 SI) will provide 667 W of power to the Global Surveyor at
aphelion. Energy will be stored in two 20 Amp-hr nickel hydrogen batteries, and supplied
at 28 V DC. Temperature control will be primarily passive with multilayer insulation,
thermal radiators, and louvers, augmented by electrical heaters. Communications will be
achieved via the deep space network using the high gain antenna and two low gain antennas,
one mounted on the high gain antenna and one on the equipment module. Uplink will be in
the X-band, downlink in the X and Ka bands. Minimum downlink rate will be 21.33 kbps, 2
kbps engineering data downlink, and 10 bps emergency downlink.