posted 04-19-2015 10:49 AM               

Space Cover #313: Mars Observer Spacecraft Disappears

The history of unmanned spacecraft exploration of planet Mars is filled with many disappointing failures, with NASA's and, especially, the Soviet Union's attempts to orbit and land spacecraft there. But there have been many spectacular successes, including both Viking 1 and Viking 2 landings on Mars in 1976, which would be included as two of NASA's greatest achievements.

However, in the failure category is the mission of Mars Observer.

Mars Observer was originally planned to be launched on the space shuttle, but the loss of Challenger in 1986 resulted in it being launched instead on a Titan III rocket. Originally budgeted to cost $212 million, it wound up costing a massive $813 million.

Mars Observer was launched on September 25, 1992 and contact with it was lost on August 22, 1993, just before achieving Mars orbit, scheduled for August 24. The two covers above have cancels from Pasadena, CA, home of JPL mission control, on the date of the scheduled Mars orbit insertion.

Unfortunately, no telemetry was received to help in determining the cause of the loss, but speculation concluded that a small propulsion leak had caused an explosion that threw the spacecraft out of control.

Following the loss of the Mars Observer, NASA has carried out a number of highly successful Mars missions, with the disappointment of Mars Observer largely overshadowed.