Editing Proton (satellite program) (section)

==Missions==

===Proton 1===

Proton 1 was launched into Earth orbit 16 July 1965 11:16&nbsp;UTC from [[Baikonur Cosmodrome Site 81/23]],<ref name=log>{{Cite web|url=http://planet4589.org/space/log/launchlog.txt|title=Launch Log|last=McDowell|first=Jonathan|publisher=Jonathon's Space Report|access-date=30 December 2018}}</ref> though the launch was threatened by a leak in the oxidizer pipeline resulting in [[nitrogen tetroxide]] spilling on electrical wires. Early in the flight, launch specialists only received signals indicating that the satellite was functioning. Eventually, however, Proton 1 performed normally, returning physics data on ultra-high-energy cosmic particles. Its mission lasted 45 days,<ref name=astro/> and the satellite reentered Earth's atmosphere 11 October 1965.<ref name=cat>{{Cite web|url=https://www.planet4589.org/space/log/satcat.txt|title=Satellite Catalog|last=McDowell|first=Jonathan|publisher=Jonathon's Space Report|access-date=23 October 2020}}</ref> 

===Proton 2===

The virtually identical Proton 2 was launched 2 November 1965 12:28&nbsp;UTC, also from Baikonur Cosmodrome Site 81/23.<ref name=log/> It reentered Earth's atmosphere on 6 February 1966.<ref name=cat/> At the time of their launch, American experts believed the first Protons were experimental space station components due to their weight and the Soviet use of the word "station" in describing the observatory satellites.<ref name=avweek1965d>{{cite magazine| date = 8 November 1965| title = News Digest (Soviets launched)| url = http://archive.aviationweek.com/issue/19651108#!&pid=24| magazine = Aviation Week and Space Technology| location = New York| publisher = McGraw Hill Publishing Company| access-date = 23 October 2020}}</ref><ref name="aa1965a">{{cite web|url=https://history.nasa.gov/AAchronologies/1965.pdf|title=Aeronautics and Astronautics, 1965|publisher=NASA|page=333|access-date=24 April 2020}}</ref>

===Proton 3===

[[File:Gt11fig3a.gif|thumb|150px|alt=Proton 3 as seen from [[Gemini 11]], 13 September 1966|Proton 3 as seen from Gemini 11, 13 September 1966<ref name=macc>{{cite web|url=http://www.brumac.mysite.com/Gemini_11/GEMINI_11.html|title=Gemini 11 UFO|author=Bruce S. Maccabee|date=August 2000}}</ref>]]

After an unsuccessful launch of the third test UR-500 on 24 March 1966 14:39&nbsp;UTC, Proton 3 was successfully launched into Earth orbit from Baikonur Cosmodrome Site 81/23 on 6 July 1966 12:57&nbsp;UTC<ref name=log/> on the fourth and final UR-500 test flight<ref name=astro/> and began searching for quarks and other elementary particles of fractional electron charge.<ref name=sov/> The satellite returned data for most, if not all, of its short time in orbit,<ref name="aa1966">{{cite web|url=https://history.nasa.gov/AAchronologies/1966.pdf|title=Aeronautics and Astronautics, 1966|publisher=NASA|page=285|access-date=26 August 2021}}</ref> reentering Earth's atmosphere on 16 September 1966.<ref name=cat/> Shortly before reentry, Proton 3 was observed tumbling once per second over the [[Indian Ocean]] by the crew of [[Gemini 11]].<ref name=avweek1966>{{cite magazine| date = 19 September 1966| title = Gemini 11 Demonstrates Pilot Capabilities| url = http://archive.aviationweek.com/issue/19660919#!&pid=26| magazine = Aviation Week and Space Technology| location = New York| publisher = McGraw Hill Publishing Company|page=27|access-date = 25 August 2021|url-access=subscription}}</ref>

===Proton 4===

After the end of the run of UR-500 test launches, the rocket (now designated Proton) and its successors were largely employed in the launch of the [[Zond program|Zond]] lunar spacecraft. However, on 16 November 1968 11:40&nbsp;UTC, the final and much larger Proton 4 was launched into orbit via [[Proton-K]] rocket from [[Baikonur Cosmodrome Site 81/24]] to continue the search for the quark and supplement the earlier Proton satellites' cosmic ray measurements.<ref name=sov/> This final Proton reentered Earth's atmosphere on 24 July 1969.<ref name=cat/>