Nuclear engine for space exploration undergoes testing

28 November 2012

Researchers are now testing a prototype small nuclear reactor that could be used in the near future to power deep-space exploration probes, especially those that extend beyond Mars.

The design is based on the Stirling engine invented in the 19th century, which uses hot pressurized gas to push pistons, according to a report on

"Beyond Mars, sunlight is so weak that solar panels would have to be football-field-sized in order to eke out enough power to run a spacecraft and transmit data back to Earth," said. NASA tests scaled-down prototype

Scientists at the National Aeronautics and Space Administration’s (NASA's) Glenn Research Center and Los Alamos National Laboratory are testing a prototype based on the design.

The prototype engine uses a small nuclear source and a single Stirling engine that produced about 24 watts of energy.

A scaled-up version of the engine would use a 50-pound nuclear uranium battery that can produce heat. Eight Stirling engines will use the heat to produce about 500 watts of power.

But much work is needed as most deep-space probes require about 600 to 700 watts of power.

"If (such engines) are created, such reactors would help keep scientists busy exploring the giant outer planets and all their moons for decades to come. Stirling engines could also be used to power a robotic probe on Venus, generating enough power to keep the machine cool in the midst of the planet’s hellish surface temperatures," said.

First nuclear engine test since 1965

On the other hand, noted this is the first test of a nuclear reactor system to power a spacecraft conducted in the U.S. since 1965.

NASA has used plutonium-238 to power its deep-space probes, including the Voyager spacecrafts and the Cassini mission now in orbit around Saturn.

But starting in the early 1980s, the U.S. began decommissioning its plutonium production sites and could no longer generate new plutionium-238 by 1992.

In 2011, NASA and the Department of Energy received about $10 million to restart plutonium production, and may generate a few pounds of the material each year.

While such a small amount will be coveted for deep-space missions, a nuclear Stirling engine using more abundant uranium would reduce the demand for plutonium-238. — TJD, GMA News