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Written by Colin Deng
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Sunday, 30 January 2005 |
| In the previous paragraphs, we discussed solar modules
provided electric power for space missions on Mars. As missions become
more ambitious and complex, power needs increases, scientists investigated
various options to meet these challenging power requirements. One of the
options was nuclear energy. |
The nuclear energy comes from heat produced by nuclear fission. There are
more compact ways of generating electricity from the heat produced by fission.
NASA's Galileo Probe which reached Jupiter in 1995 was designed to take
pictures of the planet and perform a range of scientific tests in Jupiter's
atmosphere. Unfortunately, because Jupiter is so far from the sun, powering
the equipment on board using solar energy would have been impossible. So,
NASA came up with another solution. They designed a special self-contained
power source called a Radioisotope Thermoelectric Generator (RTG). |
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Radioisotope Thermoelectric Generator (RTG)
The RTG will provide power for many years, enabling mission scientists
and program managers to extend the life of the spacecraft by several years
and in turns reap more scientific benefits. No failures of spacecraft
have been attributed by the RTG over the past 30 years in regions of space
where the use of solar power is not feasible. The systems of RTG are safe,
proven, reliable, maintenance free, and capable of producing either heat
or electricity for decades under remote harsh environment such as in Mars
exploration. The unique characteristics of these systems make them especially
suited for applications when large arrays of solar cells are not practical.
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| The first RTG produced only 2.7 watts of electric power. The most recently
designed system, the General Purpose Heat Source RTG (GPHS-RTG), generates
about 290 watts of electric power. The first system that was launched, a
SNAP-3B unit (SNAP, systems for nuclear auxiliary power), provided only
partial power for the Navy Transit 4 satellite. DOE provided three RTGs
for NASA's Cassini mission to Saturn. The Cassini spacecraft, launched to
Saturn on October 15, 1997, required three GPHS-RTGs - approximately 870
watts electric. The RTGs are the only source of onboard electric power. |
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| With such amount of electric power provided by RTGs and solar
sell at daytime, it is enough to power all of the scientific instruments,
radio transmitters, and cameras on the mother ship and recharge the sub
ships. |
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Last Updated ( Saturday, 09 July 2005 )
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