Editing Sputnik 1 (section)

=== Launch vehicle preparation and launch site selection ===
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 | image1 = R-7 (7A) misil.svg
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 | caption1 = R-7 Semyorka ICBM
 
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[[File:1967 CPA 3496.jpg|right|thumb|upright|[[Ruble|30 kopek]] USSR [[Postage stamps and postal history of Russia|stamp]] depicting Sputnik 1 orbiting the Earth, the Earth orbiting the Sun and the Sun orbiting the centre of the Milky Way galaxy]]
[[File:1957-10-07 New Moon.ogv|thumb|One of the first reports of Sputnik 1 by Universal Newsreel on 7 October 1957]]
{{Main|Sputnik (rocket)|R-7 Semyorka}}
The R-7 rocket was initially designed as an [[intercontinental ballistic missile]] (ICBM) by OKB-1. The decision to build it was made by the [[Central Committee of the Communist Party of the Soviet Union]] and the Council of Ministers of the USSR on 20 May 1954.<ref>{{cite web |url=http://www.arms.ru/nuclear/R7.htm |publisher=Arms.ru |language=ru |access-date=10 January 2013 |title=Межконтинентальная баллистическая ракета Р-7 |archive-url=https://web.archive.org/web/20120307172826/http://www.arms.ru/nuclear/R7.htm |archive-date=7 March 2012 |url-status=live|trans-title=Intercontinental ballistic missile R-7}}</ref> The rocket was the most powerful in the world; it was designed with excess thrust since they were unsure how heavy the hydrogen bomb payload would be.<ref>{{cite web|url=https://usatoday30.usatoday.com/money/topstories/2007-09-30-3949485139_x.htm|title=Sputnik at 50: An improvised triumph|last1=Isachenkov|first1=Vladimir|agency=Associated Press|work=USA Today|date=30 September 2007|access-date=13 July 2019}}</ref> The R-7 was also known by its GRAU (later GURVO, the Russian abbreviation for "Chief Directorate of the Rocket Forces") designation 8K71.<ref>Zaloga, p. 232.</ref> At the time, the R-7 was known to NATO sources as the T-3 or M-104,<ref name="CoxStoiko69">Cox & Stoiko, p. 69.</ref> and Type A.<ref>Bilstein, p. 387.</ref>

Several modifications were made to the R-7 rocket to adapt it to 'Object D', including upgrades to the main engines, the removal of a {{cvt|300|kg|lb|adj=on}} radio package on the booster, and a new payload fairing that made the booster almost four meters shorter than its ICBM version.<ref>{{cite web |last1=Zak |first1=Anatoly |title=Sputnik-3 |url=http://www.russianspaceweb.com/sputnik3.html |archive-url=https://web.archive.org/web/20071005112056/https://www.russianspaceweb.com/sputnik3.html |archive-date=5 October 2007 |publisher=RussianSpaceWeb.com}}</ref><ref name=":23">{{Cite web |last=Siddiqi |first=Asif A. |date=2023-03-29 |title=Korolev, Sputnik, and The International Geophysical Year |url=https://history.nasa.gov/sputnik/siddiqi.html |website=NASA History Division: Sputnik and the Dawn of the Space Age |publisher=National Aeronautics and Space Administration}}</ref> Object D would later be launched as [[Sputnik 3]] after the much lighter 'Object PS' (Sputnik 1) was launched first.<ref>Lanius, et al, p. 38</ref> The trajectory of the launch vehicle and the satellite were initially calculated using [[arithmometer]]s and six-digit trigonometric tables. More complex calculations were carried out on a newly-installed computer at the [[Academy of Sciences of the Soviet Union|Academy of Sciences]].<ref name=":23"/>

A special [[reconnaissance]] commission selected Tyuratam for the construction of a rocket [[proving ground]], the 5th Tyuratam range, usually referred to as "NIIP-5", or "GIK-5" in the post-Soviet time. The selection was approved on 12 February 1955 by the Council of Ministers of the USSR, but the site would not be completed until 1958. Actual work on the construction of the site began on 20 July by military building units.<ref>{{cite web |url=http://www.russianspaceweb.com/baikonur_origin.html |title=Origin of the test range in Tyuratam |year=2015 |first1=Anatoly|last1=Zak |publisher=RussianSpaceWeb.com |access-date=27 December 2015 |archive-url=https://web.archive.org/web/20151123203845/http://www.russianspaceweb.com/baikonur_origin.html |archive-date=23 November 2015 |url-status=live}}</ref>

The first launch of an R-7 rocket (8K71 No.5L) occurred on 15 May 1957. A fire began in the Blok D [[Booster (rocketry)#Strap-on|strap-on]] almost immediately at liftoff, but the booster continued flying until 98 seconds after launch when the strap-on broke away and the vehicle crashed {{convert|400|km|mi|abbr=on}} downrange.<ref name="AR7">{{cite web|url=http://www.astronautix.com/lvs/r7.htm |title=R-7|archive-url=https://web.archive.org/web/20110629074344/http://www.astronautix.com/lvs/r7.htm |archive-date=29 June 2011|url-status=dead|publisher=Encyclopedia Astronautica|last1=Wade|first1=Mark}}</ref> Three attempts to launch the second rocket (8K71 No.6) were made on 10–11 June, but an assembly defect prevented launch.<ref>{{cite web|url=http://www.energia.ru/english/energia/launchers/rocket-r7.html|title=S.P.Korolev RSC Energia – Launchers|website=www.energia.ru|access-date=4 October 2007|archive-url=https://web.archive.org/web/20170109062006/http://www.energia.ru/english/energia/launchers/rocket-r7.html|archive-date=9 January 2017|url-status=live}}</ref> The unsuccessful launch of the third R-7 rocket (8K71 No.7) took place on 12 July.<ref name="AR7" /> An [[electrical short]] caused the [[vernier engine]]s to put the missile into an uncontrolled roll which resulted in all of the strap-ons separating 33 seconds into the launch. The R-7 crashed about {{convert|7|km|mi|abbr=on}} from the pad.<ref name="RR7">{{cite web|url=http://www.russianspaceweb.com/r7.html|title=R-7 family of launchers and ICBMs|archive-url=https://web.archive.org/web/20071004091253/https://www.russianspaceweb.com/r7.html |archive-date=4 October 2007|publisher=RussianSpaceWeb.com|first1=Anatoly|last1=Zak}}</ref>

The launch of the fourth rocket (8K71 No.8), on 21 August at 15:25 [[Moscow Time]],<ref name="AR7" /> was successful. The rocket's core boosted the dummy warhead to the target altitude and velocity, reentered the atmosphere, and broke apart at a height of {{convert|10|km|mi|abbr=on}} after traveling {{convert|6000|km|mi|abbr=on}}. On 27 August, the [[Telegraph Agency of the Soviet Union|TASS]] issued a statement on the successful launch of a long-distance multistage ICBM. The launch of the fifth R-7 rocket (8K71 No.9), on 7 September,<ref name="AR7" /> was also successful, but the dummy was also destroyed on atmospheric re-entry,<ref name="RR7" /> and hence needed a redesign to completely fulfill its military purpose. The rocket, however, was deemed suitable for satellite launches, and Korolev was able to convince the State Commission to allow the use of the next R-7 to launch PS-1,<ref>Harford, p. 127.</ref> allowing the delay in the rocket's military exploitation to launch the PS-1 and PS-2 satellites.<ref name="NKA" /><ref>{{cite web |url=http://www.novosti-kosmonavtiki.ru/content/numbers/237/36.shtml |trans-title=Creation and Launch of the First Earth's Satellite |author=V.Poroshkov |publisher=Novosti Kosmonavtiki |script-title=ru:Создание и запуск Первого спутника Земли |archive-url=https://web.archive.org/web/20110606033433/http://www.novosti-kosmonavtiki.ru/content/numbers/237/36.shtml |archive-date=6 June 2011 |language=ru |access-date=10 January 2013}}</ref>

On 22 September a modified R-7 rocket, named [[Sputnik (rocket)|Sputnik]] and indexed as 8K71PS,<ref name="Siddiqi, p. 163">Siddiqi, p. 163.</ref> arrived at the proving ground and preparations for the launch of PS-1 began.<ref>[http://www.nkau.gov.ua/gateway/news.nsf/NewsALLR/BC8D1101C20C9643C3256BB90039079F!open 45th Anniversary of the First Start of Native ICBM R-7] {{Webarchive|url=https://web.archive.org/web/20090108023258/http://www.nkau.gov.ua/gateway/news.nsf/NewsALLR/BC8D1101C20C9643C3256BB90039079F!open |date=8 January 2009}} at Ukrainian Aerospace Portal {{in lang|ru}}</ref> Compared to the military R-7 test vehicles, the mass of 8K71PS was reduced from {{convert|280|to|272|t|lb}}, its length with PS-1 was {{convert|29.167|m|ftin}} and the [[thrust]] at liftoff was {{convert|3.90|MN|abbr=on|lk=on}}.<ref name="rswsputniklv">{{cite web|url=http://www.russianspaceweb.com/sputnik_lv.html|title=Sputnik launch vehicle 8K71PS (M1-1PS)|publisher=RussianSpaceWeb.com|access-date=4 October 2007|archive-url=https://web.archive.org/web/20151211204512/http://www.russianspaceweb.com/sputnik_lv.html|archive-date=11 December 2015|url-status=live|first1=Anatoly|last1=Zak}}</ref>