High-Tech Stirling Engines May Revolutionize Space Probes

The ultimate in 19th century efficiency might just make a comeback as a power source for space probes. The stirling engine, an engine as well known for its lack of power as it is for its ability to run off almost no heat, might make a perfect companion for the stars in a post-plutonium world.

Space Probes and Plutonium

If a probe has travelled further than solar panels can support, then it has probably been powered by a chunk of decaying plutonium. Plutonium is an ideal energy source for distant probes: even a small chunk burns hot, which is perfect for generating power in the cold of space. That heat also keeps the probes from freezing and failing.

But there’s a problem: all the plutonium we have came from the cold war. And our supply is running out. We’ve tried making deals with the Russians for more, but they’ve been reluctant to give it to us. So we’re left to seek out new ways of powering our crafts, if we want to keep flying space probes

Stirling Engines in Space

The stirling engine is a 200 year old design. Using clever mechanics, it is able to spin (slowly) off of pretty much any heat source. Often you can set a sterling engine to motion with the heat of your hand, if you’re patient. It works this way because it is a heat exchange engine, and a simple one at that.

But what if you have a more potent power source, like, say, a chunk of plutonium? That’s what some NASA scientists wanted to know. Turns out, with a prototype they called the Advanced Stirling Radioisotope Generator, that they can increase energy production by 4 times.

Of course, the traditional thermocouple-based design for power generation doesn’t rely on any moving parts, and thermocouples weigh less than stirling engines. But as we don’t have much plutonium left, the stirling engine might be the best option we have remaining.

NewScientist Photo by : D Guisinger