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Sputnik 21



Sputnik 21 was an attempted Venus flyby mission. The SL-6/A-2-e launcher put the craft into Earth orbit, but the third stage exploded, destroying the spacecraft.

This spacecraft was originally designated Sputnik 25 in the U.S. Naval Space Command Satellite Situation Summary.

Alternate Names

  • Alpha Pi 1
  • Sputnik 25 (USNSC)
  • 00389

Facts in Brief

Launch Date: 1962-09-12
Launch Vehicle: Modified SS-6 (Sapwood) with 2nd Generation Upper Stage + Escape Stage
Launch Site: Tyuratam (Baikonur Cosmodrome), U.S.S.R
Mass: 6500.0 kg

Funding Agency

  • Unknown (U.S.S.R)


  • Planetary Science

Additional Information

Questions or comments about this spacecraft can be directed to: Dr. David R. Williams.


Selected References

Shelton, W., Soviet space exploration - the first decade, Arthur Barker Ltd., Unnumbered, London, England, 1969.

Harvey, B., The new Russian space programme from competition to collaboration, John Wiley & Sons, Chichester, England, 1996.

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