Editing Explorer 3 (section)

==Background==
Explorer 3 was the third satellite in the Explorer small satellite series, which started with [[Explorer 1]], America's first artificial satellite.<ref name="Vanguard">{{cite book|title=''Vanguard — a History''|author=Constance Green and Milton Lomask|publisher=National Aeronautics and Space Administration|location=Washington D.C.|date=1970|id=SP-4202|isbn=978-1-97353-209-5|oclc=747307569|pages=17–18|url=https://www.hq.nasa.gov/office/pao/History/SP-4202/begin.html|access-date=21 February 2021|archive-date=3 March 2016|archive-url=https://web.archive.org/web/20160303213422/http://www.hq.nasa.gov/office/pao/History/SP-4202/begin.html|url-status=live}}</ref>{{rp|288}} The Explorer program was a direct successor to the [[Army Ballistic Missile Agency]] (ABMA)'s [[Project Orbiter]], initiated in November 1954 to use a slightly modified [[PGM-11 Redstone|Redstone]] missile<ref name=redstone53>{{cite web|url=https://history.redstone.army.mil/ihist-1953.html|title=Installation History 1953 - 1955|publisher=U.S. Army Aviation and Missile Life Cycle Management Command|date=2017|access-date=1 February 2021|archive-date=2 February 2023|archive-url=https://web.archive.org/web/20230202195242/https://history.redstone.army.mil/ihist-1953.html|url-status=live}}</ref> combined with solid-propellant rocket cluster upper stage to put a satellite into orbit.<ref name="Vanguard"/>{{rp|17-18, 43}}

In 1955, the "Stewart Committee", under the chairmanship of [[Homer J. Stewart]] of [[Jet Propulsion Laboratory]] (JPL), chose a [[Naval Research Laboratory]] (NRL) satellite plan using a rocket based on its [[Viking (rocket)|Viking]] rocket ([[Project Vanguard]]) for the [[International Geophysical Year]], which would start 1 July 1957.<ref name="Vanguard"/>{{rp|43, 51-56}} Nevertheless, ABMA hoped Redstone-Orbiter could still be used as a backup orbital system. Reentry tests that year conducted with the newly developed, Redstone-based [[Jupiter-C]], further strengthened ABMA confidence in their vehicle as an orbital launcher. 

Following the launch of the Soviet satellite [[Sputnik 1]] on 4 October 1957, Project Orbiter was revived,<ref name="space age">{{cite web|url=https://www.nasa.gov/history/sputnik/expinfo.html|title=Explorer Info|work=NASA History |publisher=NASA|access-date=20 Oct 2024}}</ref>  with two shots authorized as a back-up to Vanguard in early November.<ref name="Vanguard"/>{{rp|238}} The failure of America's [[Vanguard TV-3|first attempted Vanguard launch]] on 6 December 1957,<ref name = "Kaputnik">
{{Cite news
| last1          = Wilder
| first1         = Paul
| title          = Tribune Reporter Writes Eyewitness Story of Fiery Death Of Satellite Rocket 
| work           = [[Tampa Morning Tribune]]
| publisher      = The Tribune Company
| issn           = 1042-3761

| date           = 7 December 1957
| page           = 1
| url            = https://www.newspapers.com/article/the-tampa-tribune-tribune-reporter-write/168923658/

| access-date    = 26 March 2025
| via            = [[Newspapers.com]]
}}</ref> cleared the way for an "Explorer" (as the crash program was dubbed) to be the first American satellite.<ref name="Vanguard"/>{{rp|74,199-200, 212-213}}

Working closely together, ABMA and JPL completed the job of modifying the Jupiter-C to the Juno 1 and building Explorer 1 in 84 days.<ref name="space age">{{cite web|url=https://www.nasa.gov/history/sputnik/expinfo.html|title=Explorer Info|work=NASA History |publisher=NASA|access-date=20 Oct 2024}}</ref> An experiment developed for Vanguard by George Ludwig,<ref name="Vanguard"/>{{rp|238}} comprising an Anton 314 omnidirectional Geiger tube detector for measuring the flux of high energy charged protons and electrons, was adapted for Explorer 1.<ref name=explorer1exp>{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1958-001A-01|title=Cosmic Ray Detector|accessdate=22 October 2024|publisher=NASA}}</ref> Because of the high spin rate of the Explorer 1 rocket, the experiment's tape recorder had to be omitted, which meant that data could only be collected when the satellite was in sight and range of a ground station.<ref name="Vanguard"/>{{rp|238}}

Explorer 1 took off 31 January 1958, becoming America's first satellite. Its Geiger tube worked properly, but acted contrary to expectations. As the satellite ascended in its orbit, the radiation count increased, then abruptly dropped to zero. When the satellite was descending, the tube abruptly began detecting charged particles again. As data could only be received about 15% of the time, it was yet impossible to determine the phenomenon Explorer had detected.<ref name="Vanguard"/>{{rp|241-242}}