Editing Cosmic Background Explorer (section)

== History ==
In 1974, NASA issued an Announcement of Opportunity for astronomical missions that would use a small- or medium-sized [[Explorer program|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 orbit|polar-orbiting]] satellite called COBE to be launched by either a [[Delta 5000|Delta 5920-8]] [[launch vehicle]] or the [[Space Shuttle]]. It would contain the following instruments:<ref name=leverington>{{cite book |last1=Leverington |first1=David |title=New Cosmic Horizons: Space Astronomy from the V2 to the Hubble Space Telescope |publisher=Cambridge University Press |date=2000 |isbn=0-521-65833-0}}</ref>

{| class="wikitable"
|+Instruments
! Instrument
! Acronym
! Description
! Principal Investigator
|-

| Differential Microwave Radiometer
| DMR
| [[Microwave]] instrument that would map variations (or anisotropies) in the Cosmic microwave background (CMB) radiation
| [[George F. Smoot III]]
|-

| [[Diffuse Infrared Background Experiment]]
| DIRBE
| Multiwavelength infrared detector used to map dust emission
| Michael G. Hauser
|-

| Far-InfraRed Absolute Spectrophotometer
| FIRAS
| Spectrophotometer used to measure the spectrum of the CMB
| [[John C. Mather]]
|-
|}

[[File:COBELaunch.jpg|thumb|upright=1.0|right|Launch of the COBE spacecraft on 18 November 1989.]]

NASA accepted the proposal provided that the costs be kept under US$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]] [[Vacuum flask|dewar]] on COBE would be similar to those used on Infrared Astronomical Satellite (IRAS).

COBE was originally planned to be launched on a [[Space Shuttle]] mission [[Canceled Space Shuttle missions|STS-82-B]] in 1988 from [[Vandenberg Space Force Base|Vandenberg Air Force Base]], but the [[STS-51-L|Challenger explosion]] delayed this plan when the Shuttles were grounded. NASA prevented COBE's engineers from going to other space companies to launch COBE, and eventually a redesigned COBE was placed into [[Sun-synchronous orbit]] on 18 November 1989 aboard a Delta launch vehicle.

On 23 April 1992, COBE scientists announced at the [[American Institute of Physics|APS April Meeting]] in [[Washington, D.C.]] the finding of the "primordial seeds" (CMBE anisotropy) in data from the DMR instrument; until then the other instruments were "unable to see the template."<ref>{{Cite news |last=Schewe |first=Phillip F. |last2=Stein |first2=Ben |date=1992-04-24 |title=COBE PICKS OUT PRIMORDIAL SEEDS AT LAST |volume=77 |work=The AIP Bulletin of Physics News |url=https://www.aip.org/pnu/1992/split/pnu077-1.htm |url-status=dead |access-date=2023-07-23 |archive-url=https://web.archive.org/web/20061023083330/https://www.aip.org/pnu/1992/split/pnu077-1.htm |archive-date=2006-10-23}}</ref> The following day ''[[The New York Times]]'' ran the story on the front page, explaining the finding as "the first evidence revealing how an initially smooth cosmos evolved into today's panorama of stars, galaxies and gigantic clusters of galaxies."<ref>{{Cite news |last=Wilford |first=John Noble |date=1992-04-24 |title=SCIENTISTS REPORT PROFOUND INSIGHT ON HOW TIME BEGAN |language=en-US |work=The New York Times |url=https://www.nytimes.com/1992/04/24/us/scientists-report-profound-insight-on-how-time-began.html |access-date=2023-07-23 |issn=0362-4331}}</ref>

The Nobel Prize in Physics for 2006 was jointly awarded to John C. Mather, NASA [[Goddard Space Flight Center]], and George F. Smoot III, [[University of California, Berkeley]], "for their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation".<ref>{{cite web |url=http://nobelprize.org/nobel_prizes/physics/laureates/2006/index.html |title=The Nobel Prize in Physics 2006 |publisher=Nobel Foundation |access-date=2008-10-09}}</ref>