After a 17-year gap since its last mission to the red planet, the United States launched Mars Observer on September 25, 1992. The spacecraft was based on a commercial Earth-orbiting communications satellite that had been converted into an orbiter for Mars. The payload of science instruments was designed to study the geology, geophysics and climate of Mars.
The mission ended with disappointment on August 22, 1993, when contact was lost with the spacecraft shortly before it was to enter orbit around Mars. Science instruments from Mars Observer are being reflown on two other orbiters, Mars Global Surveyor and 2001 Mars Odyssey.
- High-resolution camera
- Thermal emission spectrometer
- Laser altimeter
- Magnetometer/Electron reflectometer
- Pressure modulator infrared radiometer
- Gamma ray spectrometer
- Radio science experiment
Spacecraft Mass: 5,672 Pounds
Mars Observer did very little science during its cruise phase to Mars to save on costs, but approximately two months of total data from the gamma ray spectrometer were successfully collected, including spectral observations of one burst, GB930706, for which the VLA obtained radio observations approximately eight days later. Preliminary analysis of the Mars Observer data also shows some information for approximately twenty other burst sources detected by Ulysses and Compton Observatory, though none triggered the Gamma Ray Spectrometer to interrupt its mapping functions to observe the source directly.