Mars Observer
Mars Observer — a NASA orbiter launched on 25 September 1992 to study the surface, atmosphere, climate and magnetic field of Mars. On 22 August 1993 (UTC), two days before it was due to enter orbit, its radio was switched off as planned while its propellant tanks were pressurised, and it was never heard from again. The investigation board found the most probable cause to be a failure in its propulsion system. Copies of its instruments flew on later Mars orbiters. (Its position here is representative.)
Key facts
Mission & specifications
Mission
- Operator
- NASA / JPL
- Launched
- September 25, 1992
- Status
- Lost
Trajectory
- Distance from the Sun
- 1.58 AU
- Computed from the cached position
- Distance from Earth
- 1.54 AU
- Computed from cached positions
- Distance from Mars
- 619,629 km
- Computed from cached positions
Mission
Mars Observer, built by Martin Marietta for NASA's Jet Propulsion Laboratory, was launched on a Titan III rocket from Cape Canaveral on 25 September 1992 at 17:05 UTC; a Transfer Orbit Stage sent it on toward Mars. The 1,018 kg orbiter was to study the surface, atmosphere, climate and magnetic field of Mars from a low polar orbit. After eleven months and 725 million km of cruise, on 21 August 1993, three days before its engine was to fire to put it into orbit, controllers began pressurising its propellant tanks, and as planned its transmitter was switched off during the operation. Its telemetry stopped on schedule at 00:40 UTC on 22 August, as received on Earth, and did not return at 00:54 as it should have. No signal from Mars Observer has been received since. NASA's investigation board found no conclusive evidence, but concluded that the most probable cause was a massive failure of the pressurisation side of the propulsion system, most probably from nitrogen tetroxide and monomethyl hydrazine mixing unintentionally in its titanium tubing. Whether the silent spacecraft then went into orbit around Mars or flew past into orbit around the Sun is not known. Copies of its instruments flew on Mars Global Surveyor, Mars Climate Orbiter and 2001 Mars Odyssey.
- 1992Mars Observer launches toward Mars on a Titan III rocketLaunch
With a Transfer Orbit Stage to send it on its way.
- 1993Contact lostMission end
Its transmitter is switched off as planned while its tanks are pressurised, and never comes back.
Images
Images from open archives · credit shown per image