June 27, 2011 - Satellite Power is a SNAP

Satellite Power is a SNAP In the 1950s, many people believed that nuclear generators would one day power our cities, heat our homes, and eliminate our dependence on coal and oil. These predictions did not pan out on the scale originally envisioned, but one area where nuclear power did excel is in providing power for spacecraft. The first satellite to carry a nuclear power source was the Navy’s Transit 4A satellite, which was launched fifty years ago this week. Its Space Nuclear Auxiliary Power (SNAP) 3B generator provided 2.7 watts of power. Since then, nuclear power has been a mainstay for many spacecraft, especially those too far from the Sun to rely on solar power. The Cassini spacecraft, which took this image, is powered by three nuclear generators, each 100 times more powerful than SNAP 3B.

Image credit: NASA / JPL / Space Science Institute

Weekly Calendar

June 27 - July 3, 2011

Holidays - Sky Events - Space History

Moon phase Monday 27

1982: STS-4 Columbia launched
1995: STS-71 Atlantis launched
1997: NEAR-Shoemaker probe flies by asteroid Mathilde

Moon phase Tuesday 28

Pluto at opposition
Mars 1.7° south of Moon

Moon phase Wednesday 29

1868: George Ellery Hale born
1961: Transit 4A launched, first nuclear-powered satellite
1971: Soyuz 11 crew dies during reentry

Moon phase Thursday 30

1908: Tunguska impact levels hundreds of miles of Siberian forest
2001: WMAP spacecraft launched

Moon phase Friday 1

Canada Day (Canada)

New Moon 4:54 AM ET

1917: 100” mirror arrives at Mt. Wilson Observatory
1972: Wernher von Braun retires from NASA
1997: STS-94 Columbia launched

Moon phase Saturday 2

Mercury 5° north of Moon

1985: European Space Agency launches Giotto probe to study Halley’s Comet

Moon phase Sunday 3

1935: Harrison Schmitt born

Suggestions for new history dates or better links? Corrections for errors on this page? Please e-mail me.