Future spacecraft may be powered with nuclear energy

CAPE CANAVERAL, Fla. -- The ability to explore planets beyond our solar system will require the use of space vehicles with nuclear-powered propulsion systems, NASA administrator Sean O'Keefe said Tuesday.

Using nuclear power on future spacecraft could cut the time it takes to reach the edge of our solar system from 15 years to five years, O'Keefe told several hundred people attending Space Congress, an annual space industry conference in Cape Canaveral.

NASA's past efforts to use nuclear power in space has met opposition from environmentalists. In 1997, hundreds of people protested the launching of the Cassini interplanetary robot craft, which was powered by plutonium.

Developing the new propulsion system has been allotted $3 billion over five years in NASA's budget and given the name Project Prometheus. Besides making space trips speedier, it would also "enhance the ability of our robotic spacecraft to perform scientific investigations of planets," O'Keefe said.

If used on manned spacecraft, nuclear propulsion would mean astronauts spend less time in space, reducing the amount of radiation exposure and bone and muscle loss they experience, he said.

"We could do these kinds of things safely," O'Keefe added.

Although he doesn't know details about Project Prometheus, Frank Jackalone, Florida staff director of the Sierra Club, said NASA has shown that the space program isn't risk-free.

Jackalone's group opposed the Cassini launch. "There is no way NASA can say for certain that something is 100 percent safe."

NASA has previously used nuclear energy to power spacecraft but never in a propulsion system. Currently, space ships are launched with rocket power, but once in space they rely on momentum to carry them to their goal, since they cannot carry enough heavy rocket fuel to continue accelerating through space.

Development of nuclear fusion or fission engines would enable a space vehicle to continue increasing its speed once away from Earth, shortening the time needed to reach distant planets. These engines also could provide electrical power instead of relying on solar cells or batteries, making it possible to operate more scientific instruments.

During his speech to the Space Congress, O'Keefe reiterated his goal to have space shuttles flying by the end of the year.

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