For the first time in nearly 50 years, NASA has used a small prototype of a nuclear-reactor engine design to test whether this could one day power deep-space exploration probes.

Although nuclear energy has many strengths, pun intended, it’s not very popular lately. This could be a very good use of it however because for space, we kind of need the development of a small/light-weight, long-lasting power source for long-term space missions, or for ideas like Elon Musk has.

Remarkably, the new proposed design is modelled on an engine first invented in the 19th century – one that uses hot pressurised gas to push a piston – called a Stirling engine. The concept is virtually as simple as a steam engine. Scientists at NASA’s Glenn Research Center and Los Alamos National Laboratory have tested a small prototype using a small nuclear source to produce about 24 watts of energy. The issue: they need about 600 to 700 watts of power for a decent deep-space probe.

Their proposed design would use a 22 kilogram nuclear uranium battery to generate heat that is then carried to eight Stirling engines to produce about 500 watts of power. Solar powered exploration beyond Mars becomes a bit difficult, because sunlight weakens, and you can’t exactly send a spacecraft with a rugby field-sized solar panel into orbit very easily.

The other issue is this: plutonium-238. Plutonium-238 is what NASA has been using to power most of its deep-space exploration, as Wired explains:

NASA has used plutonium-238 to power its deep-space probes, including theVoyager spacecraft’s and the Cassini mission currently in orbit around Saturn. But beginning in the early 1980s, the U.S. began decommissioning its plutonium production sites and by 1992 had no way to generate new plutionium-238. NASA’s Curiosity rover, which is right now driving around Mars, carried some of the last bits of American plutonium with it to the Red Planet.

In 2011, NASA and the Department of Energy received about $10 million to restart plutonium production, and should soon be capable of generating a few pounds of the material each year. This tiny amount will be highly coveted for deep-space missions. A nuclear Stirling engine that generates electricity using more-abundant uranium would reduce the demand for plutonium-238.

Well done science.

[Source: Wired]