Soyuz 7K-L1 No.4L was launched at 22:11:54 UTC on 27 September 1967 atop a Proton-K 8K78K carrier rocket with a Blok D upper stage, flying from Site 81/23 at the Baikonur Cosmodrome.

The booster eventually lost attitude control and became unstable during flight, so the automatic shutdown command was sent at T+97 seconds and it crashed downrange.

The spacecraft separated from the rocket by means of the SAS launch escape system, and came down between 50 and 60 kilometres (31 and 37 mi) downrange.

The next morning, recovery crews located the descent module, however approaching it was tricky due to spilled propellant and still-burning booster debris in the area.

[5] Prior to the release of information about its mission, NASA correctly identified that it had been a test of a spacecraft intended for crewed Lunar flights.