Editing Project Vanguard (section)

=== Sputnik and Explorer 1 ===
[[File:Vanguard rocket explodes.jpg|thumb|upright|left|Vanguard rocket explodes seconds after launch at Cape Canaveral (December 6, 1957).]]

The original schedule called for the TV3 to be launched during the month of September 1957, but because of delays this did not happen.<ref name=PM/> On October 4, 1957, the Vanguard team learned of the launch of [[Sputnik 1]] by the [[Soviet Union|USSR]] while still working on a test vehicle (TV-2) designed to test the first stage of their launcher rocket. While demoralizing to the Vanguard team, Minitrack was successful in tracking Sputnik, a major success for NRL.<ref>{{cite web|last1=Green|first1=Constance McLaughlin|last2=Lomask|first2=Milton|title=Vanguard: A History|url=http://history.nasa.gov/SP-4202/chap11.html|website=NASA History|publisher=National Aeronautics and Space Administration|access-date=28 April 2015}}</ref> At 11:44:35&nbsp;a.m. on December 6, an attempt was made to launch TV-3. The [[Vanguard (rocket)|Vanguard rocket]] rose about {{cvt|4|ft|m|order=flip}} into the air when the engine lost thrust, and the rocket immediately sank back down to the launch pad and exploded. The payload nosecone detached and landed free of the exploding rocket, the small satellite's radio beacon still beeping.<ref>Stehling, Kurt (1961) Project Vanguard</ref><ref name="ley196810">{{Cite magazine
 |last=Ley
 |first=Willy
 |date=October 1968
 |title=The Orbit of Explorer-1
 |department=For Your Information
 |url=https://archive.org/stream/Galaxy_v27n03_1968-10#page/n93/mode/2up
 |magazine=Galaxy Science Fiction
 |pages=93–102
}}</ref> The satellite was too damaged for further use; it now resides in the [[National Air and Space Museum]].

After the Soviet Union launched [[Sputnik 2]], on November 3, 1957, then [[United States Secretary of Defense|Secretary of Defense]] [[Neil H. McElroy]] directed the [[United States Army|U.S. Army]] to use the [[Juno I]] and launch a satellite.<ref>{{Cite web|url=https://history.redstone.army.mil/space-explorer.html|title=The United States Army|access-date=14 May 2015|archive-date=3 July 2015|archive-url=https://web.archive.org/web/20150703022718/http://history.redstone.army.mil/space-explorer.html|url-status=live}}</ref> On January 31, 1958, the U.S. Army launched the [[Explorer 1]] satellite. With the launch of Sputnik 1 and 2 the previous concern, the right of satellite overflight, had become moot: those satellites were launched by an early version of the Soviet [[R-7 Semyorka|R-7 rocket]], the basis of the USSR's early ICBMs, and definitely military, as well as roughly 40 times larger than the Vanguard launcher.

[[File:Vanguard TV3.jpg|thumb| [[Vanguard TV3]] in previous display at the National Air and Space Museum. The antenna rods should extend radially from the body of the satellite, but are bent as a result of damage sustained in the launch failure.]]

On March 17, 1958, the program successfully launched the Vanguard satellite TV-4. TV-4 achieved a stable orbit with an [[Apsis|apogee]] of {{convert|3,969|km|mi|abbr=off|sp=us}} and a [[Apsis|perigee]] of {{convert|650|km|mi|abbr=off|sp=us}}. It was estimated that it would remain in orbit for at least 240 years, and it was renamed Vanguard I, which in addition to its upper launch stage remains the oldest human-made satellite still in orbit.

In late 1958, with responsibility for Project Vanguard having been transferred to [[NASA]], the nucleus of the [[Goddard Space Flight Center]] was formed. After four failed launches, the program once again succeeded with SLV-4, renamed Vanguard II.<ref>{{cite web|last1=Green|first1=Constance McLaughlin|last2=Lomask|first2=Milton|title=Vanguard: A History|url=http://history.nasa.gov/SP-4202/chap12.html|website=NASA History|publisher=National Aeronautics and Space Administration|access-date=28 April 2015}}</ref> After two more failures, the program ended with the launch of Vanguard III in 1959.