Cosmic Background Explorer

Cosmic Background Explorer
	Artist's concept of the COBE spacecraft
Names	Explorer 66
Mission type	Cosmic microwave background Astronomy
Operator	NASA
COSPAR ID	1989-089A
SATCAT no.	20322
Website	lambda.gsfc.nasa.gov/product/cobe
Mission duration	6 months (planned); 4 years, 1 month and 4 days (achieved)
Spacecraft properties
Spacecraft	Explorer LXVI
Spacecraft type	Cosmic Background Explorer
Bus	COBE
Manufacturer	Goddard Space Flight Center
Launch mass	2,206 kg (4,863 lb)
Dry mass	1,408 kg (3,104 lb)
Dimensions	5.49 × 2.44 m (18.0 × 8.0 ft)
Power	750 watts
Start of mission
Launch date	18 November 1989, 14:34 UTC
Rocket	Delta 5920-8 (Delta 189)
Launch site	Vandenberg, SLC-2W
Contractor	Douglas Aircraft Company
Entered service	18 November 1989
End of mission
Deactivated	23 December 1993
Orbital parameters
Reference system	Geocentric orbit
Regime	Sun-synchronous orbit
Perigee altitude	900 km (560 mi)
Apogee altitude	900 km (560 mi)
Inclination	99.00°
Period	103.00 minutes
Instruments
	Differential Microwave Radiometer (DMR); Diffuse Infrared Background Experiment (DIRBE); Far-InfraRed Absolute Spectrophotometer (FIRAS)
	; Cosmic Background Explorer mission patch Explorer program ← AMPTE-CCE (Explorer 65) Extreme Ultraviolet Explorer (Explorer 67) →

The Cosmic Background Explorer (COBE /ˈkoʊbi/ KOH-bee), also referred to as Explorer 66, was a NASA satellite dedicated to cosmology, which operated from 1989 to 1993. Its goals were to investigate the cosmic microwave background radiation (CMB or CMBR) of the universe and provide measurements that would help shape our understanding of the cosmos.

COBE's measurements provided two key pieces of evidence that supported the Big Bang theory of the universe: that the CMB has a near-perfect black-body spectrum, and that it has very faint anisotropies. Two of COBE's principal investigators, George F. Smoot and John C. Mather, received the Nobel Prize in Physics in 2006 for their work on the project. According to the Nobel Prize committee, "the COBE project can also be regarded as the starting point for cosmology as a precision science".^[4]

COBE was the second cosmic microwave background satellite, following RELIKT-1, and was followed by two more advanced spacecraft: the Wilkinson Microwave Anisotropy Probe (WMAP) operated from 2001 to 2010 and the Planck spacecraft from 2009 to 2013.

^ "COBE Mission Design, Spacecraft and Orbit". Goddard Space Flight Center. 18 April 2008. Retrieved 21 July 2015.
^ Crouse, Megan (16 July 2015). "Cosmic Background Explorer". Product Design & Development. Retrieved 21 July 2015.^{[permanent dead link]}
^ "Trajectory: COBE (1989-089A)". NASA. 28 October 2021. Retrieved 27 November 2021. This article incorporates text from this source, which is in the public domain.
^ "The Nobel Prize in Physics 2006". The Royal Swedish Academy of Sciences. 3 October 2006. Retrieved 23 August 2011.

[gsfcOverview-1] "COBE Mission Design, Spacecraft and Orbit". Goddard Space Flight Center. 18 April 2008. Retrieved 21 July 2015.

[pddnet-2] Crouse, Megan (16 July 2015). "Cosmic Background Explorer". Product Design & Development. Retrieved 21 July 2015.^{[permanent dead link]}

[Trajectory-3] "Trajectory: COBE (1989-089A)". NASA. 28 October 2021. Retrieved 27 November 2021. This article incorporates text from this source, which is in the public domain.

[4] "The Nobel Prize in Physics 2006". The Royal Swedish Academy of Sciences. 3 October 2006. Retrieved 23 August 2011.

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