Article · Wikipedia archive · Last revised Jul 20, 2026

Kosmos 300

Kosmos 300 was the fourth Soviet attempt at an uncrewed lunar sample return. It was probably similar in design to the later Luna 16 spacecraft. It was launched, on a Proton rocket, 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.

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Jul 20, 2026
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Kosmos 300
A Ye-8-5 model in the Museum of Cosmonautics, Moscow.
Mission typeLunar sample-return
OperatorSoviet space program
COSPAR ID1969-080A
SATCAT no.4104
Mission duration4 days
Spacecraft properties
Spacecraft typeYe-8-5
ManufacturerGSMZ Lavochkin
Launch mass5,600 kg (12,300 lb)1
Start of mission
Launch dateSeptember 23, 1969, 14:07:00 (1969-09-23UTC14:07Z) UTC2
RocketProton-K/D
Launch siteBaikonur 81/24
End of mission
DisposalLaunch failure
Decay dateSeptember 27, 1969
Orbital parameters
Reference systemGeocentric2
Perigee altitude184 km (114 mi)
Apogee altitude189 km (117 mi)
Inclination51.5°
Period88.2 min

Kosmos 300 (Russian: Космос 300 meaning Cosmos 300) (Ye-8-5 series) was the fourth Soviet attempt at an uncrewed lunar sample return. It was probably similar in design to the later Luna 16 spacecraft. It was launched, on a Proton rocket, on September 23, 1969.3 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.4

References

References

  1. "Cosmos 300". nssdc.gsfc.nasa.gov. NASA. Retrieved 25 May 2024.
  2. Mark Wade. "Luna Ye-8-5". Encyclopedia Astronautica. Retrieved 25 May 2024.
  3. "Luna - Exploring the Moon". orbitalfocus.uk. Retrieved 23 February 2023.
  4. Asif Siddiqi (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF) (second ed.). NASA History Program Office. p. 92. ISBN 978-1-626-83043-1.