Jet Propulsion Laboratory (U.S.). Mars Observer Project.

The Mars Observer spacecraft was to be the first United States spacecraft to study Mars since the Viking missions in the 1970's. On September 25, 1992, Mars Observer, (formerly known as the Mars Geoscience/Climatology Orbiter Project), was lofted into low Earth orbit at 1:05 p.m. EDT aboard the 145-foot tall Martin Marietta Titan III rocket booster from the Kennedy Space Center's Launch Complex 40, at Cape Canaveral, Florida.

After a 15-minute ride into orbit, the spacecraft was then positioned for its course to Mars by a second rocket booster; the Transfer Orbit Stage (TOS), which fired to break the spacecraft free of Earth's gravity. Technicians had discovered some minor electrical problems in the TOS, which was making its flight debut, in the weeks before launch, but they seemed confident that all was well.

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