History
In 1974, NASA issued an Announcement of Opportunity for astronomical missions that would use a small- or medium-sized Explorer spacecraft. Out of the 121 proposals received, three dealt with studying the cosmological background radiation. Though these proposals lost out to the Infrared Astronomical Satellite (IRAS), their strength made NASA further explore the idea. In 1976, NASA formed a committee of members from each of 1974's three proposal teams to put together their ideas for such a satellite. A year later, this committee suggested a polar-orbiting satellite called COBE to be launched by either a Delta rocket or the Space Shuttle. It would contain the following instruments:
| Instrument | Acronym | Description | Principal Investigator |
|---|---|---|---|
| Differential Microwave Radiometer | DMR | a microwave instrument that would map variations (or anisotropies) in the CMB | George Smoot |
| Far-InfraRed Absolute Spectrophotometer | FIRAS | a spectrophotometer used to measure the spectrum of the CMB | John Mather |
| Diffuse InfraRed Background Experiment | DIRBE | a multiwavelength infrared detector used to map dust emission | Mike Hauser |
NASA accepted the proposal provided that the costs be kept under $30 million, excluding launcher and data analysis. Due to cost overruns in the Explorer program due to IRAS, work on constructing the satellite at Goddard Space Flight Center (GSFC) did not begin until 1981. To save costs, the infrared detectors and liquid helium dewar on COBE would be similar to those used on IRAS.
COBE was originally planned to be launched on a Space Shuttle mission STS-82-B in 1988 from Vandenberg Air Force Base, but the Challenger explosion delayed this plan when the Shuttles were grounded. NASA kept COBE's engineers from going to other space agencies to launch COBE, but eventually, a redesigned COBE was placed into sun-synchronous orbit on November 18, 1989 aboard a Delta rocket. A team of American scientists announced, on April 23, 1992, that they had found the primordial "seeds" (CMBE anisotropy) in data from COBE. The announcement was reported worldwide as a fundamental scientific discovery and ran on the front page of the New York Times.
The Nobel Prize in Physics for 2006 was jointly awarded to John C. Mather, NASA Goddard Space Flight Center, and George F. Smoot, University of California, Berkeley, "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation."
Read more about this topic: Cosmic Background Explorer
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