Kosmos 638Rocket launchby RussiaLaunch time3 Apr 197407:30 UTCsuccessOrbit: LEOUnmanned test of upgraded Soyuz spacecraft for the Apollo–Soyuz Test Project.MissionRocketPayloadsLandingRocket SoyuzUlaunched from Baikonur Cosmodrome, Pad 31/6KazakhstanPayloadsNamePurposeMassCommentKosmos 638 (Soyuz 7K-TM)---Spacecraft landingDate13 Apr 1974