12 February 2004
Labs look to nuke juice for space missions
By Sue Vorenberg
Albuquerque Tribune Reporter


"Impulse drive, Mr. Scott."

Scientists controlling robotic space missions could be using variants of the familiar Star Trek command to control robotic spacecraft within a decade, New Mexico nuclear lab researchers think.

By using nuclear energy, space vehicles will be able to roam the solar system at a leisurely pace and visit individual planets or moons for months at a time, say a group of Los Alamos and Sandia national laboratories scientists.

"Chemical propulsion - which is what most space systems use today - can  get you to the far planets, but you don't have enough power to stop and visit," said Jim Lee, a Los Alamos scientist. "They actually only have enough power that you can basically just fly by and wave, maybe take a few readings or pictures. Nuclear power, on the other hand, will let us stick around for a while."

Scientists at the two labs are helping the National Aeronautics and Space Administration and private industry design a new stable of nuclear  energy systems that could be deployed on a variety of future space missions, Lee said.

"I think what we're doing here - kind of like the Wright brothers - is creating the first form of impulse drive for our Starship Enterprise," Lee said. "We haven't figured out how to do warp drive, but this will let us slowly move around a solar system in the same way that they do on Star Trek."

Both labs have experimented with nuclear power technology for spacecraft since the 1950s. In the past year, however, they've refocused their efforts to make designs that are more practical and less expensive, said Mike Houts, a Los Alamos scientist.

The soonest such a reactor might be launched is in 2011 on NASA's Jupiter Icy Moons Orbiter mission, which will explore four of Jupiter's moons - each the size of a small planet with varying environments and geologies, Houts said.

Protests that nuclear power would be inherently dangerous have met the labs' work on the technology, but the nuclear power sources would be activated only after the craft is out in space, the scientists say.

"It's important to note that these vehicles aren't launched with nuclear power," said Paul Pickard, a Sandia scientist. "They're launched with chemical systems, and the reactor is turned on much later - when the craft is far away from the Earth's biosphere."

Until now, space vehicles have been powered by chemical engines, radioisotopes and solar power.

The problem with solar energy is that beyond the asteroid belt - toward planets like Jupiter and Saturn - the sun's rays aren't strong enough to power a craft, Lee explained.

Chemical energy is also a problem because it is heavy and quickly used up. And radioisotopes, such as plutonium - which provide energy in the form of heat and natural radioactive decay - can only provide a limited amount of energy, perhaps enough to power several light bulbs, he added.

"With nuclear power we get about a million times more power than we do with chemical or other energy types," Pickard said. "With it, we can run a spacecraft for years at a time. We could do a 10-year mission. That's impossible to conceive of any other way."

Paradoxically, in manned space travel the use of nuclear engines could save astronauts from exposure to excessive radiation, Pickard said.

"There's a lot of natural radiation in space anyway, from a variety of sources," he said. "When you think of manned missions to places like Mars, you want to minimize the time astronauts are in space and exposed to that radiation. The ironic thing is that we can reduce their exposure to radiation by using nuclear propulsion to speed their trip."


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