Kosmos 300 (russian: Космос 300 meaning ''Cosmos 300'') (Ye-8-5 series) was the fourth Soviet attempt at an unmanned

lunar Lunar most commonly means "of or relating to the Moon". Lunar may also refer to: Arts and entertainment * ''Lunar'' (series), a series of video games * "Lunar" (song), by David Guetta * "Lunar", a song by Priestess from the 2009 album ''Prior t ...

sample return A sample-return mission is a spacecraft mission to collect and return samples from an extraterrestrial location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as lo ...

. It was probably similar in design to the later

Luna 16 ''Luna 16'' was an uncrewed space mission, part of the Soviet Luna program. It was the first robotic probe to land on the Moon and return a sample of lunar soil to Earth. The 101 grams (3.56 ounces) sample was returned from Mare Fecunditatis. ...

spacecraft. It was launched, on a

Proton rocket Proton (Russian: Протон) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965. Modern versions of the launch system are sti ...

, on September 23, 1969. The mission was a failure. The engines on the Block D upper stage failed due to an oxidizer leak, leaving the spacecraft to burn up in Earth's atmosphere.

References

Luna programme Kosmos satellites Sample return missions Missions to the Moon Spacecraft launched in 1969 {{USSR-spacecraft-stub