Editing Explorer 1 (section)

== Flight ==
[[File:Explorer 1 launch control console Huntsville Space museum.jpg|thumb|right|Explorer 1 launch control console on display at Huntsville Space and Rocket Center. The red arrow points to the manually turned launch key switch.]]

After a jet stream-related delay on 28 January 1958, at 03:47:56 GMT on 1 February 1958 <ref name="ley196810">{{cite magazine |url=https://archive.org/details/Galaxy_v27n03_1968-10/page/n93/mode/2up?view=theater |title=The Orbit of Explorer 1 |magazine=[[Galaxy Science Fiction]] |last=Ley |first=Willy |pages=93–102 |date=October 1968 |access-date=30 July 2024}}</ref> the Juno I rocket was launched, putting Explorer 1 into orbit with a [[Apsis|perigee]] of {{cvt|358|km}} and an [[Apsis|apogee]] of {{cvt|2550|km}} having a period of 114.80 minutes, and an [[Orbital inclination|inclination]] of 33.24°.<ref name="Trajectory">{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1958-001A |title=Trajectory: Explorer-1 1958-001A |publisher=NASA |date=14 May 2020 |access-date=12 February 2021}} {{PD-notice}}</ref><ref name="solarsystem">{{cite web |url=http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Explorer_01 |title=Solar System Exploration Explorer 1 |publisher=NASA |access-date=2008-02-06 |archive-url=https://web.archive.org/web/20080108105558/http://solarsystem.nasa.gov/missions/profile.cfm?MCode=Explorer_01 |archive-date=2008-01-08 |url-status=dead}} {{PD-notice}}</ref> [[Goldstone Deep Space Communications Complex|Goldstone Tracking Station]] could not report after 90 minutes as planned whether the launch had succeeded because the orbit was larger than expected.{{r|ley196810}} At about 06:30 GMT, after confirming that Explorer 1 was indeed in orbit, a news conference was held in the Great Hall at the [[National Academy of Sciences]] in [[Washington, D.C.]] to announce it to the world.<ref name="Discovering Earth's Radiation Belts: Remembering Explorer 1 and 3">{{cite journal |title=Discovering Earth's Radiation Belts: Remembering Explorer 1 and 3 |journal=NASA History |author=McDonald, Naugle |year=2008 |volume=89 |pages=361–363 |number=39 |doi=10.1029/2008EO390001 |bibcode=2008EOSTr..89..361M |publisher=NASA}} {{PD-notice}}</ref>

[[File:Explorer 1 launch control manual mission plot Huntsville Space museum.jpg|thumb|right|Hand drawn Explorer 1 mission plot]]

The original expected lifetime of the satellite before [[orbital decay]] was three years.{{r|ley196810}} [[Mercury batteries]] powered the high-power transmitter for 31 days and the low-power transmitter for 105 days. Explorer 1 stopped transmission of data on 23 May 1958,<ref name="Zadunaisky">{{cite journal |first=Pedro E. |last=Zadunaisky |title=The Orbit of Satellite 456 Alpha (Explorer 1) during the First 10500 Revolutions |date=October 1960 |bibcode=1960SAOSR..50.....Z |journal=SAO Special Report |volume=50}}</ref> when its batteries died, but remained in orbit for more than 12 years.<ref>{{Cite magazine |date=October 1968 |url=http://archive.org/details/Galaxy_v27n03_1968-10 |author-link=Willy Ley |last=Ley |first=Willy |title=The Orbit of Explorer-1 |department=For Your Information |magazine=Galaxy Science Fiction |pages=[https://archive.org/details/Galaxy_v27n03_1968-10/page/n93/mode/2up?view=theater 93]-102 |volume=27 |issue=3 |quote=The original estimate of the lifetime of Explorer-1, made a week or so after firing, was three years. It has been orbiting for ten years by now and the estimate of its remaining lifetime is again three years, but this time surrounded by careful explanations about the factors we don't know.}}</ref> It reentered the atmosphere over the [[Pacific Ocean]] on 31 March 1970 after more than 58,400 orbits.