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How important is nuclear power to space exploration?

Our science question of the month.
April 2, 2018
Artist's illustration of the umbrella-like heat radiators of four Kilopower nuclear reactors

Artist's illustration of the umbrella-like heat radiators of four Kilopower nuclear reactors casting shadows on the Martian surface. CREDIT: NASA

Where more energy is needed, such as for a facility on Mars, multiple KRUSTY units could be deployed.

There are really only two practical ways to create electrical energy for multi-year space missions: solar or nuclear power. However, for missions into deep space, solar capture isn’t feasible because there are places in the universe where, almost literally, “the sun don’t shine” (or at least not enough to generate adequate power). Closer to home there could be other issues. For instance, with a post on Mars, solar panels would be problematic given that the sun’s intensity varies throughout the year and dust storms can persist for months.

Enter nuclear power. The Laboratory—in conjunction with NASA and the Department of Energy—is in the process of testing a power system that can work in harsh environments and is efficient, reliable, safe, low cost, and compact. Named KRUSTY (short for kilopower reactor using Stirling technology), it’s designed to provide between 1 and 10 kilowatts of power (an average home uses about 5 kilowatts of electricity at its peak). Where more energy is needed, such as for a facility on Mars, multiple KRUSTY units could be deployed.

Although some might have concerns about the nuclear reactor involved, until KRUSTY is activated there are really very few safety concerns; it uses less than five curies of naturally occurring radioactivity. Plus, the reactor only activates once it reaches its destination (in deep space, on another planet, or in high orbit). After that, the system is self-regulating, owing to simple reactor physics.

Even in the event of a launch problem, the potential radiation consequences would be less than that experienced by exposure to normal background radiation or from a cross-country airline flight. 

KRUSTY builds on previous research dating back to 1965. The current system uses Stirling engines and heat-pipe technology (the latter invented at Los Alamos National Laboratory) to keep the design simple.

So, in answer to the original question, nuclear power will be vital to long-term space exploration.

Pat McClure, System Design and Analysis

You can learn more at NASA’s Kilopower site.

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