This spacecraft, a 7K-L1 type, was the first of a series of spacecraft that the Soviets tried to send on circumlunar missions as part of a larger project to send two cosmonauts around the Moon.
The program, which was officially approved in Oct. 1965, involved combining forces between two of the leading space organizations in the Soviet Union, those headed by Vasiliy Mishin (1917-2001) (who provided the 7K-L1 spaceship and the Blok D translunar injection stage) and Vladimir Chelomey (1914-1984) (who provided the 3-stage Proton-K launch vehicle).
The 7K-L1 spacecraft was a stripped-down version of the larger 7K-OK Soyuz spacecraft intended for Earth-orbital operations. The proximate goal was to send two cosmonauts around the Moon by the 50th anniversary of the Bolshevik Revolution in Nov. 1967.
The project moved into a new stage with two technological flights in Earth orbit in March and April 1967, which involved high-speed reentries.
During this particular launch, the ascent was steady for 61 seconds before diverting from a nominal path, which activated the emergency rescue system into action. The 7K-LI descent module immediately separated from the wandering launch vehicle, and although the capsule was destabilized at the moment of separation because of an unexpected pressure shock, it landed safely in one piece not far from wreckage of the booster, which was destroyed at T+97.4 seconds.
Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.