Kosmos 27, also known as Zond 3MV-1 No.3 was a space mission intended as a Venus impact probe. The spacecraft was launched by a Molniya 8K78 carrier rocket from Baikonur. The Blok L stage and probe reached Earth orbit successfully, but the attitude control system failed to operate. Kosmos 27 was launched at 03:24:43 GMT on 27 March 1964, atop a Molniya 8K78 s/n T15000-22 carrier rocket flying from Site 1/5 at the Baikonur Cosmodrome. Kosmos 27 was a "third-generation" deep space planetary probes of the 3MV series of the Soviet Union. The Soviet engineers planned four types of the 3MV, the 3MV-1 (for Venus impact), 3MV-2 (for Venus flyby), 3MV-3 (for Mars impact), and 3MV-4 (for Mars flyby).

Wikipedia: https://en.wikipedia.org/wiki/Kosmos_27. Original timeline Wikipedia link: https://en.wikipedia.org/wiki/Cosmos_program. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1964. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).