Leonard David's INSIDE OUTER SPACE

NASA’s Kilopower project: The power level would be suitable to access, extract, and process lunar ice in permanently shadowed craters and demonstrate propellant production.
Credit: NASA

Important strides are being made in building and testing a key energy source that literally “empowers” human crews on the Moon. NASA’s Space Technology Mission Directorate (STMD) has provided multi-year funding for the Kilopower project. This work is viewed as a stepping stone to small fission-powered planetary science missions – including how to energize a lunar outpost.

Building on prior work by a joint NASA and Department of Energy team, the main goal is to assemble and test an experimental prototype of a space fission power system.

In a May 2 NASA briefing, Kilopower officials announced that the experiment was successfully carried out from November 2017 through March 2018 at the Nevada National Security Site. The effort is led by NASA’s Glenn Research Center in Ohio to demonstrate space fission power systems technology.

Small and simple

The pioneering reactor is a small and simple approach for long-duration, sun-independent electric power for space or extraterrestrial surfaces. Offering high design margins for life and reliability, it will produce from one to 10 kilowatts of electrical energy, continuously for 10 years or more, explains Lee Mason, STMD’s Principal Technologist for Power and Energy Storage at NASA Headquarters. The power system uses a solid, cast uranium-235 reactor core, about the size of a paper towel roll. Reactor heat is transferred via passive sodium heat pipes with that heat then converted to electricity with high efficiency Stirling engines. They churn out about four times as much electric power from the plutonium fuel as compared to a space-rated radioisotope thermoelectric generator (RTG).

For Apollo expeditions to the Moon, RTGs powered five Apollo Lunar Surface Experiment Packages (ALSEPs) set up by moonwalking crews.
Credit: NASA

Apollo power

A historical flashback: For Apollo expeditions to the Moon, RTGs powered five Apollo Lunar Surface Experiment Packages (ALSEPs) set up by moonwalking crews. Those packages contained scientific instruments that relayed information back to Earth, such as data on solar wind and radiation, and the observation that the Moon is geologically active. The five ALSEP stations were shut down in 1977.

“What we are striving to do,” Mason says, “is give space missions an option beyond RTGs which provide a couple hundred watts or so. A Moon mission for Kilopower would be ideal. It has the potential to power lander payloads through the lunar night, and possibly for months or years. The power level would be suitable to access, extract, and process lunar ice in permanently shadowed craters and demonstrate propellant production. NASA could also co-develop the system with commercial lunar lander companies that supply power to mining ventures or small settlements,” he told Inside Outer Space.

Credit: LANL/NASA

Confidence-builder

A successful lunar campaign using Kilopower technology could be a confidence-builder for later Mars missions where humans would depend on the fission power system to make their return propellant and power their habitats.

Having a space-rated fission power unit for future lunar explorers is a game changer, Mason adds. “This new technology is in the kilowatt-class and can mature to provide hundreds of kilowatts of power, or even megawatts. That’s why we call it the Kilopower project. But first things first, and our test program is the way to do it.”