||The poor fiscal climate for planetary science in the 1980s led NASA officials to conceive of a new, low-cost series of planetary science missions to be called the Planetary Observer line, based on commercially-built Earth orbiters. The basic concept was to reduce costs by buying the spacecraft on a fixed-price contract and selecting only scientific instruments that were already mature. In other words, the Observer line would not develop new technology. Things didn't quite work out that way. The first, and only, Planetary Observer built was Mars Observer.
Mars Observer was approved in 1985 for a 1990 launch. The destruction of Space Shuttle Challenger led to a lengthy delay. NASA reduced the Shuttle's flight rate after the accident and also shifted some of Mars Observer's funds to the Cosmic Background Explorer mission, delaying Mars Observer still further. NASA finally decided to launch Mars Observer in 1992 on a Titan III expendable rocket instead of from the Shuttle. Originally budgeted at $212 million, Mars Observer wound up costing $813 million. By the time it was launched on Sept. 25, 1992, Mars Observer had come to symbolize out-of-control costs.
Mars Observer disappeared Aug. 22, 1993, right before entering Mars orbit. The flight team had just ordered the spacecraft to pressurize its propulsion system; an independent failure investigation board concluded that a tiny amount of leakage through some of the valves had caused a small explosion, throwing the spacecraft permanently out of control. This determination was somewhat speculative, however, as JPL had received no telemetry at all from the spacecraft, and its propulsion specialists could not replicate this proposed failure mechanism on duplicate hardware.
Regardless of cause, Mars Observer's loss was traumatic for the lab. It was JPL's first complete mission failure since Mariner 8's loss in a launch accident in 1971. The JPL staff had grown accustomed to succeeding. It was also the first Mars mission in 17 years, and many of JPL's old hands were Mars enthusiasts. Recovering from the Mars Observer failure became a major priority for both NASA and JPL.