Nuclear reactor space travel, NASA news: Heat pipe, Stirling engine could power future space flights

For potential power sources on space flights beyond the horizon, scientists are looking back to the future.

A team of NASA and Department of Energy researchers has shown that a reliable nuclear reactor based on technology that's been around for decades could be used in spaceships, according to a news release from the Los Alamos National Laboratory, where some of the researchers are based.

The news release says the team used "heat pipe technology," which was invented at Los Alamos in 1963, and uses a heat pipe to cool a small nuclear reactor and power a Stirling engine, producing 24 watts of electricity.

The experiment known as the Demonstration Using Flattop Fissions, or DUFF, is the first demonstration of a space nuclear reactor system to produce electricity in the United States since 1965, and the experiment confirms basic nuclear reactor physics and heat transfer for a simple, reliable space power system.

A heat pipe is a sealed tube with fluid inside that can efficiently transfer heat produced by a reactor with no moving parts. According to a video on Los Alamos' YouTube channel, over the past 50 years, heat pipes have "gone mainstream" and now are used in everything from electronics to the Alaska pipeline.

Stirling engines, which the Los Alamos video says were initially developed in the 19th century, are relatively simple, closed-loop engines that convert heat energy into electrical power using a pressurized gas to move a piston.

Using the two devices in tandem allowed for creation of a simple, reliable electric power supply that can be adapted for space applications, the release said.

"The heat pipe and Stirling engine used in this test are meant to represent one module that could be used in a space system," said Marc Gibson of NASA Glenn Research Center. "A flight system might use several modules to produce approximately 1 kilowatt of electricity."

In the video, Los Alamos says the primary benefits of this nuclear technology are its simplicity, and its reliance on resources the United States has "in abundance."

In addition, the scientists say because the reactor wouldn't function until it was in space, accidents on the ground or during launch would have minimal impact.

"A small, simple, lightweight fission power system could lead to a new and enhanced capability for space science and exploration," said Los Alamos project lead Patrick McClure. "We hope that this proof of concept will soon move us from the old frontier of Nevada to the new frontier of outer space."