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Mission record

Mars Observer

Also known as Mars Geoscience/Climatology Orbiter, MGCO, MarsObserver

NASA-Office of Space Science Applications, Centre National d'Etudes Spatiales, Russian Space Agency · Launched

Explore trajectory

Lost · Failure

Mars Observer, the first of the Observer series of planetary missions, was designed to study the geoscience and climate of Mars. Its primary science objectives were to determine the global elemental and mineralogical character of the surface material, define globally the topography and gravitational field, establish the nature of the Martian magnetic field, determine the distribution and abundance of volatiles and dust over a seasonal cycle, and explore the structure and circulation of the atmosphere. Contact with Mars Observer was lost on August 21, 1993, three days before scheduled orbit insertion, for unknown reasons and has not been re-established; it is not known whether the spacecraft was able to follow its automatic programming and go into Mars orbit or if it flew by Mars and is now in a heliocentric orbit. Although none of the primary objectives of the mission were achieved, cruise mode data were collected up to loss of contact.

Destinations
Launch vehicle
Titan III
Launch site
Cape Canaveral, United States
Countries
United States, France, Soviet Union
Mission types
Orbiter

Chronology

Mission timeline

  1. Launch

    Launched on a Titan III

    NSSDCA's launch/orbital information page gives the launch date and time as 1992-09-25T17:05:01Z on a Titan III from Cape Canaveral, United States. The bus and electronics of the Observer series of spacecraft, used to study the terrestrial planets and near-Earth asteroids, were derived from the Satcom-K and DMSP/TIROS spacecraft, and the rectangular bus section was 2.1 x 1.5 x 1.1 m. The same page gives one interplanetary cruise about the Sun, with an epoch start of 1992-09-26 00:00:00 and no epoch stop.

    Earth

  2. Loss of contact

    Contact lost three days before scheduled orbit insertion

    Contact with Mars Observer was lost on August 21, 1993, three days before scheduled orbit insertion, for unknown reasons and has not been re-established. It is not known whether the spacecraft was able to follow its automatic programming and go into Mars orbit or if it flew by Mars and is now in a heliocentric orbit. Later investigation concluded the most probable cause of the mishap was a fuel line rupture during fuel tank pressurization which would have caused the spacecraft to spin uncontrollably. NSSDCA's chronology of Mars exploration reads Mars Observer - 25 September 1992 - Attempted Mars Orbiter (Contact Lost), and because the master catalog page says it is not known whether the spacecraft entered orbit, no orbit-insertion and no flyby is recorded here.

    Mars

Mission architecture

Vehicles

  • Mars Observer · Orbiter

    Destinations: Mars

Trajectory record

Trajectory dataset not yet available

No verified trajectory dataset is committed for this mission, so Mission Atlas renders no path.

Provenance

Sources

Each source is listed once and labeled with the mission, event, trajectory, or destination/body context it supports.

Data verified through September 2, 2026