Encyclopedia Astronautica
Mars Observer



marsob.jpg
Mars observor
Credit: NASA
American Mars orbiter. One launch, 1992.09.25. Mars Observer was a NASA mission to study the surface, atmosphere, interior and magnetic field of Mars from Martian orbit.

The mission was designed to operate for one full Martian year (687 Earth days) to permit observations of the planet through its four seasons.

The mission specific objectives were to (1) determine the global elemental and mineralogical character of Mars' surface material, (2) define the planet's global topography and gravitational field, (3) establish the nature of the Martian magnetic field, (4) determine the time and space distribution, abundance, sources and sinks of volatile material and dust over a seasonal cycle, (5) explore the structure and aspects of the circulation of the Martian atmosphere. The spacecraft also carried a radio relay package designed to receive information from the planned Mars Balloon Experiment carried on the planned Soviet Mars '94 mission for retransmission back to Earth. Communications was lost with the spacecraft on 22 August 1993 as it was preparing to go into orbit around Mars, and no significant scientific data was returned. Later investigation indicated this was due to a propulsion system explosion caused by propellants leaking past faulty valves.

The spacecraft was based on Earth-orbiting spacecraft (DMSP and TIROS) and was 3-axis stabilized, zero momentum bias using reaction wheels. Communications with Earth used an X-band system and 1.5 m articulated high gain antenna mounted on a 6-meter boom. The deployed 3.7 x 6.5 meter solar array generated 1.1 - 1.5 kW. The hydrazine and bi-propellant propulsion systems performed trajectory maneuvers, Mars orbit capture and circularization, and orbit maintenance. Deployable booms provided mounting points for instruments. The payloads included:

  • Gamma-ray spectrometer (GRS) - designed to measure the abundance of elements (uranium, thorium, potassium, iron and silicon, for example) on the surface of Mars.
  • Thermal-emission spectrometer (TES) - intended to map the mineral content of surface rocks, frosts and the composition of clouds.
  • Mars Observer Camera (MOC) - a line-scan camera designed to take low-resolution images of Mars on a daily basis for studies of the climate, and medium- and high-resolution images of selected areas to study surface geology and interactions between the surface and the atmosphere. Laser altimeter - intended to measure the topographic relief of the Martian surface.
  • Pressure-modulator infrared radiometer (PMIRR) - designed to measure dust and condensates in the atmosphere, as well as profiles of temperature, water vapor and dust opacity as they change with latitude, longitude and season.
  • Radio-science investigation - planned to use the spacecraft radio with an ultrastable oscillator to measure atmospheric refractivity as it varies with altitude to determine the temperature profile of the atmosphere, and would use tracking data to measure the gravity field of Mars.
  • Magnetometer and electron reflectometer - designed to determine the nature of the magnetic field of Mars, and its interactions with the solar wind.

Gross mass: 2,573 kg (5,672 lb).
Height: 3.20 m (10.40 ft).
First Launch: 1992.09.25.
Number: 1 .

More... - Chronology...


Associated Countries
See also
  • Titan The Titan launch vehicle family was developed by the United States Air Force to meet its medium lift requirements in the 1960's. The designs finally put into production were derived from the Titan II ICBM. Titan outlived the competing NASA Saturn I launch vehicle and the Space Shuttle for military launches. It was finally replaced by the USAF's EELV boosters, the Atlas V and Delta IV. Although conceived as a low-cost, quick-reaction system, Titan was not successful as a commercial launch vehicle. Air Force requirements growth over the years drove its costs up - the Ariane using similar technology provided lower-cost access to space. More...

Associated Launch Vehicles
  • Titan American orbital launch vehicle. The Titan launch vehicle family was developed by the United States Air Force to meet its medium lift requirements in the 1960's. The designs finally put into production were derived from the Titan II ICBM. Titan outlived the competing NASA Saturn I launch vehicle and the Space Shuttle for military launches. It was finally replaced by the USAF's EELV boosters, the Atlas V and Delta IV. Although conceived as a low-cost, quick-reaction system, Titan was not successful as a commercial launch vehicle. Air Force requirements growth over the years drove its costs up - the Ariane using similar technology provided lower-cost access to space. More...
  • Commercial Titan 3 American orbital launch vehicle. Commercial version of Titan 34D military booster. It differed in having a lengthened second stage and a 4 m diameter payload shroud to handle shuttle-class or Ariane-type dual payloads. More...

Associated Manufacturers and Agencies
  • JPL American agency;manufacturer of rockets, spacecraft, and rocket engines. Jet Propulsion Laboratory, Pasadena, USA. More...
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...

Bibliography
  • McDowell, Jonathan, Jonathan's Space Home Page (launch records), Harvard University, 1997-present. Web Address when accessed: here.
  • JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Web Address when accessed: here.
  • McDowell, Jonathan, Launch Log, October 1998. Web Address when accessed: here.

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Cape Canaveral LC40 Titan launch complex. Constructed as part of the Titan Integrate-Transfer-Launch (ITL) facility at the north end of Cape Canaveral in the early 1960s. Supported a wide variety of military space missions involving Titan IIIC, Titan 34D and Titan IV vehicles. More...

Mars Observer Chronology


1992 September 25 - . 17:05 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC40. LV Family: Titan. Launch Vehicle: Commercial Titan 3. LV Configuration: Commercial Titan 3 CT-4.
  • Mars Observer - . Payload: Mars Observer [TOS-21H]. Mass: 2,573 kg (5,672 lb). Nation: USA. Agency: JPL. Class: Mars. Type: Mars probe. Spacecraft: Mars Observer. USAF Sat Cat: 22136 . COSPAR: 1992-063A. Summary: Planned Mars orbiter; lost contact during orbit insertion burn. Solar Orbit (Heliocentric). Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B)..

1993 August 22 - .
  • Communications lost with Mars observor - . Nation: USA. Spacecraft: Mars Observer. Communications was lost with the spacecraft on August 22, 1993 as it was preparing to go into orbit around Mars, and no significant scientific data was returned. Later investigation indicated this was due to a propulsion system explosion caused by propellants leaking past faulty valves.

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