Monday, 30 July 2012

Nuclear 'a stepping stone' to space exploration

This is neat! Nuclear 'a stepping stone' to space exploration: ..."A new era of space exploration is dawning through the application of nuclear energy for rovers on Mars and the Moon, power generation at future bases on the surfaces of both and soon for rockets that enable interplanetary travel.

NASA has reported the successful tests of power conversion and radiator systems for a nuclear power system it hopes to deploy on the Moon by 2020. It is based on a small fission reactor which would heat up and circulate a liquid metal coolant mixture of sodium and potassium. The heat differential between this and the outside temperature would drive two complimentary Stirling engines to turn a 40 kWe generator. Some 100 square metres of radiators would remove process heat to space.
Using an electric heat source instead of a real reactor, the Stirling engines, generator and a section of the radiator have recently been tested - producing a steady 2.3 kWe. The tests included operation in a vacuum chamber that simulates extreme temperature swings at NASA's Glenn Research Center, and under elevated radiation levels at Sandia National Laboratory. "It is very efficient and robust," said Lee Mason of Glenn, "we believe it can last for eight years unattended."
Space missions have so far used a range of power sources: chemical energy for rocket propulsion, solar power with batteries for low-power systems and small radioisotope thermal generators for even lower power applications and to prevent damage from the cold of space. The highest power level so far generated is the 100 kWe of the International Space Station, whereas a satellite or probe might use 25 kWe from solar cells.
Nuclear energy from fission reactors can provide larger constant supplies without reliance on sunlight or the burden of heavy batteries and rocket fuel. "A lunar base needs lots of power for things like computers, life support, and to heat up rocks to get out resources like oxygen and hydrogen," said Ross Radel of Sandia. The Moon is dark for up to 14 days at a time, and Mars is so much further from the sun that solar power would not be sufficient for life-support. For those reasons, "nuclear is a stepping stone to move further out into manned space exploration," said Radel.
NASA said that current plans foresee nuclear power employed on the Moon in around 2020. However, a nuclear-powered rover named Curiosity is due to land on Mars in the next ten days."

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