Editing SM-65 Atlas (section)

===Comparison with R-7===
The [[R-7 Semyorka]] was the first Soviet ICBM and similarly started all engines before launch to avoid igniting a large liquid fuel engine at high altitudes. However, the R-7 had a central sustainer section, with four boosters attached to its sides. The large side boosters required use of an expensive launch pad and prevented launching the rocket from a silo. Like the Atlas, the use of [[cryogenic]] [[liquid oxygen]] meant that the missile could not be kept in the state of flight readiness indefinitely and was largely useless for its intended purpose (military) and was similarly developed into a space launch vehicle, initially delivering [[Sputnik 1|Sputnik]] and [[Vostok 1|Vostok]] into orbit. The [[Soyuz (rocket family)|Soyuz rocket]] is descended from the R-7 and remains in use today.<ref>{{Cite web|date=2020-04-27|script-title=ru:Коммерческий полет "Союза" на МКС планируется в 2022-2023 годах|trans-title=Soyuz commercial flight to the ISS planned for 2022-2023|url=https://ria.ru/20200427/1570605489.html|access-date=2020-06-26|website=РИА Новости|language=ru}}</ref>