spaceSpace and Physics

NASA Is Testing A Nuclear Fission Reactor That Could Power Human Missions On Mars


Jonathan O'Callaghan

Senior Staff Writer

Deep space missions could make use of the technology. NASA

NASA says it is making key strides in the development of a new nuclear fission power source that could enable human exploration of other worlds.

Called Kilopower, the $15 million project is currently in the testing phase, with a prototype reactor going through four phases of testing at the Nevada National Security Site (NNSS) from November 2017 to March 2018.


“This is a key energy source that could fuel a human crew to Mars,” said Mark Martinez, president of Mission Support and Test Services for the project, in a press conference today.

The technology revolves around using the heat generated by nuclear fission of uranium to power a Stirling engine. The key breakthrough is that this technology could allow for much higher power levels on future space missions, enabling new deep space missions and crewed missions throughout the Solar System.

The protoype is called KRUSTY, or Kilopower Reactor Using Stirling Technology. In the coming months, the team will run the reactor at full power, reaching temperatures of 800°C (1,470°F) and producing enough heat to generate a kilowatt of power.

“We’re really excited about this project,” said Steve Jurczyk, associate administrator of NASA’s Space Technology Mission Directorate. “The Kilopower project aims to demonstrate the potential for future crewed missions to the Moon’s surface, Mars, and beyond.”

A prototype is currently being tested. NASA Glenn Research Center

The eventual reactor design calls for using a cylinder of enriched uranium in the reactor core, 15 centimeters (6 inches) in diameter. It’s encased in a reflector made from beryllium oxide. In the middle of the cylinder, a rod of boron carbide is used to switch on the reaction.

Through the process of nuclear fission, the reactor produces heat. This is delivered by heat pipes to power generators known as Sterling convertors. Excess heat is emitted by a large radiator on top or around the reactor. The reactors measure about 2 meters (6.5 feet) tall.

One of these reactors by themselves could power an uncrewed spacecraft on a mission into deep space, including to the outer Solar System or even further. Using a combination of them though, they would provide an excellent power source for humans operating on the surface of Mars.

Kilopower could be essential for a future crewed mission to Mars. NASA

This is the first time NASA has tested a fission reactor intended for use in space since the 1960s. We’ve long been reliant on radioisotope thermonuclear generators (RTGs), which are basically battery fission sources, not reactors. These require plutonium-238 to work, something that’s been in short supply until recently.


“Historically, the biggest obstacle to space fission power has been the perceived development cost, largely because development of advanced nuclear technology and new test facilities can be very expensive and take many years,” an op-ed for SpaceNews noted.

“A 10-kilowatt-electric (kWe) reactor could enable ambitious nuclear electric propulsion missions to orbit and explore the outermost planets and Kuiper belt objects.”


spaceSpace and Physics
  • tag
  • nasa,

  • moon,

  • Mars,

  • mission,

  • deep space,

  • nuclear fission,

  • kilopower,

  • crewed