| Sputnik Home

Background History

Bibliography

Biographies

Chronology

Documents

Explorer

The International  Geophysical Year

Photo Gallery

Vanguard  |  | Chronology of Sputnik/Vanguard/Explorer Events 1957-58 - October 4, 1957 USSR: Sputnik 1 (83.6 kg) launched 
- November 3 USSR: Sputnik 2 (508.3 kg), with dog Laika as passenger, launched 
- December 6 USA: Vanguard TV-3 explodes on launch pad 
- January 31, 1958 USA: Explorer 1 (14 kg), America's first satellite, discoversthe Van Allen radiation belts 
- February 3 USSR: First try to launch Sputnik 3 fails 
- February 5 USA: A second Vanguard try fails 
- March 5 USA: Explorer 2 fails to orbit 
- March 17 USA: Vanguard 1 (1.47 kg) successfully orbits, establishes thepear-shapedness of the Earth 
- March 26 USA: Explorer 3 orbits, collects radiation and micrometeoroiddata 
- April 28 USA: Another Vanguard fails to orbit (third failure) 
- May 15 USSR: Sputnik 3 (1,327 kg) orbits, carrying large array of scientificinstruments, but tape recorder fails, so it can't map Van Allen belts 
- May 27 USA Vanguard fails for the fourth time 
- June 26 USA Vanguard fails for fifth time 
- July 26 USA Explorer 4 orbits and maps Van Allen radiation belts for 21/2 months 
- August 24 USA Explorer 5 fails to orbit 
- September 26 USA Vanguard fails for the sixth time
**Source:** James J. Harford, "Korolev's Triple Play: Sputniks 1,2, and 3," adapted from James J. Harford, Korolev: How One Man Mastermindedthe Soviet Drive to Beat America to the Moon (John Wiley: New York, 1997).
For further information, please email histinfo@hq.nasa.gov

Last Updated: January 27, 2005.                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|--|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|