Table 1

Summary of spacecraft tracking data.

SpacecraftPeriapsis height (km) Inclination (degrees) Tracking
Mariner 9 1600 64S-band  Doppler
Viking 1 300, 1500 39,  55S-band  Doppler
Viking 2 300, 800, 1500 55,  75,  80 S-band  Doppler
MGS 380, 263, 170 93 X-band  Doppler,  range