Editing Mars 4 (section)

== Launch ==
Mars 4 was launched by a Proton-K carrier rocket, a Blok D upper stage, flying from Baikonur Cosmodrome Site 81/23.<ref name="LL"/> The launch occurred at 19:30:59 UTC on 21 July 1973, with the first three stages placing the spacecraft and upper stage into a [[low Earth orbit|low Earth]] [[parking orbit]] before the Blok D fired to propel Mars 4 into heliocentric orbit bound for Mars.

Shortly after performing a course correction on 30 July 1973, two onboard computers failed, leaving Mars 4 unable to perform maneuvers. As a result of this, it was unable to enter orbit around Mars. Twelve photographs were taken on 10 February 1974 from 15:32 UTC to 15:38 UTC as the probe flew past Mars with a closest approach of {{convert|1844|km}} at 15:34 UTC.<ref>Siddiqi, Asif A. (2016). Beyond Earth: A Chronicle of Deep Space Exploration 1958-2016, NASA History Program Office, http://www.nasa.gov/ebooks.</ref>