Kosmos 359 was an unmanned Soviet probe launched on 22 August 1970. The probe's intended purpose was to explore Venus, but an error caused the final-stage rocket to malfunction. This left the craft trapped in an elliptical orbit around Earth for 410 days before orbital decay and atmospheric entry. Kosmos 359 was launched five days after Venera 7 and had an identical design; had the craft not suffered a mission-ending failure, it would have landed on Venus shortly after Venera 7. To publicly acknowledge the failure of the attempted Venus lander would be a public relations disaster for the Soviet space program; after the mission failed, the Venera spacecraft was renamed Kosmos 359 in order to conceal the mishap from the public.

Wikipedia: https://en.wikipedia.org/wiki/Kosmos_359. Original timeline Wikipedia link: https://en.wikipedia.org/wiki/Cosmos_program. Related NASA reference: https://nssdc.gsfc.nasa.gov/planetary/chronology.html#1970. Description adapted from Wikipedia contributors (CC BY-SA 4.0; https://creativecommons.org/licenses/by-sa/4.0/).