Encyclopedia Astronautica

American infrared astronomy satellite. One launch, 1989.11.18.

The Cosmic Background Explorer's observations of diffuse cosmic background radiation helped answer basic questions such as whether the matter in the universe was homogeneously distributed, whether the universe was uniformly expanding and rotating, and how and when stars and galaxies first formed. COBE also mapped interstellar and interplanetary dust clouds.

Originally planned for launch on the Shuttle, COBE was redesigned for launch aboard a Delta 2 following the Challenger disaster. COBE's supply of liquid helium was exhausted in September 1990, causing loss of the FIRAS instrument.

The spacecraft was spin stabilized (0.8 rpm about sunline) using 3 reaction wheels and torque rods. Attitude control knowledge (4 arcmin) was provided by magnetometers, earth sensors, sun sensors, gyros. The satellite consisted of a hexagonal spacecraft bus and a cryostat containing 95.7 kg of liquid helium for cooling sensors. This was protected against solar and terrestrial radiation by a conical shield. Deployable solar panels provided 1050W BOL. Downlink was through the TDRSS relay satellite.

The instrument payload consisted of the Differential Microwave Radiometer (DMR) to check the thermal and structural uniformity of the early universe, the Far Infrared Absolute Spectrometer (FIRAS) and the Diffuse IR Background Experiment (DIRBE), to search for the remnant radiation emitted from the primordial galaxies as they formed.

AKA: Cosmic Background Explorer.
Gross mass: 2,265 kg (4,993 lb).
Height: 5.49 m (18.01 ft).
First Launch: 1989.11.18.
Number: 1 .

More... - Chronology...

Associated Countries
See also
  • Delta The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Development began in 1955 and it continued in service in the 21st Century despite numerous candidate replacements. More...

Associated Launch Vehicles
  • Delta American orbital launch vehicle. The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Delta began as Thor, a crash December 1955 program to produce an intermediate range ballistic missile using existing components, which flew thirteen months after go-ahead. Fifteen months after that, a space launch version flew, using an existing upper stage. The addition of solid rocket boosters allowed the Thor core and Able/Delta upper stages to be stretched. Costs were kept down by using first and second-stage rocket engines surplus to the Apollo program in the 1970's. Continuous introduction of new 'existing' technology over the years resulted in an incredible evolution - the payload into a geosynchronous transfer orbit increasing from 68 kg in 1962 to 3810 kg by 2002. Delta survived innumerable attempts to kill the program and replace it with 'more rationale' alternatives. By 2008 nearly 1,000 boosters had flown over a fifty-year career, and cancellation was again announced. More...
  • Delta 5000 American orbital launch vehicle. The Delta 5000 series used the more powerful Castor 4A strap-ons but with the Extended Long Tank core with RS-27 engine. Only one was launched. More...
  • Delta 5920-8 American orbital launch vehicle. Three stage vehicle consisting of 9 x Castor 4A + 1 x ELT Thor/RS-27 + 1 x Delta K with 2.4 m (8 foot) diameter fairing) More...

Associated Manufacturers and Agencies
  • NASA American agency overseeing development of rockets and spacecraft. National Aeronautics and Space Administration, USA, USA. More...
  • Ball American manufacturer of spacecraft. Ball Aerospace and Technology, Boulder, Colorado, USA. More...

  • 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
  • Vandenberg Vandenberg Air Force Base is located on the Central Coast of California about 240 km northwest of Los Angeles. It is used for launches of unmanned government and commercial satellites into polar orbit and intercontinental ballistic missile test launches toward the Kwajalein Atoll. More...
  • Vandenberg SLC2W Delta launch complex. Originally a Thor 75 SMS launch pad. Upgraded to a space launch complex in 1966. More...

COBE Chronology

1989 November 18 - . 14:34 GMT - . Launch Site: Vandenberg. Launch Complex: Vandenberg SLC2W. LV Family: Delta. Launch Vehicle: Delta 5920-8. LV Configuration: Delta 5920-8 D189.
  • COBE - . Mass: 2,265 kg (4,993 lb). Nation: USA. Agency: NASA Greenbelt. Class: Astronomy. Type: X-ray astronomy satellite. Spacecraft: COBE. USAF Sat Cat: 20322 . COSPAR: 1989-089A. Apogee: 886 km (550 mi). Perigee: 873 km (542 mi). Inclination: 98.9000 deg. Period: 102.60 min. Summary: Cosmic Background Explorer; measured background galactic infrared radiation. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B)..

1990 September - .
  • COBE's liquid helium supply exhausted - . Nation: USA. Spacecraft: COBE. Summary: The Cosmic Background Explorer's supply of liquid helium was exhausted, causing loss of the FIRAS (Far Infrared Absolute Spectrometer) instrument..

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