Put nuclear technology in space or on the moon, and just as on Earth it can provide a power density unmatched by any other source. But what roles can nuclear power and propulsion play as the world enters a 21st-century space race? That was a key question put to six speakers during the November 14 American Nuclear Society Winter Meeting plenary session “Space: The (Next) Nuclear Frontier.”

NASA’s Artemis I mission, successfully launched at 1:47 a.m. EST on November 16 from the Kennedy Space Center in Florida, will travel 40,000 miles beyond the moon—farther from Earth than any human-crewed space mission has flown before. The historic trip was launched by the world’s largest rocket, the Space Launch System (SLS), nearly 50 years after NASA last sent humans to the moon. And while no humans are on board the Orion spacecraft, two fabricated crew members—“Luna Twins” Helga and Zohar—were assembled with thousands of sensors to obtain the best estimates yet of cosmic radiation exposure to human tissues during space travel.

ANS’s August 4 online event “The New Space Race is Going Nuclear” featured several expert panelists who discussed the growing importance of nuclear technologies in space commercialization and exploration. Although nuclear energy has long played a role in space missions, participants discussed the latest exciting developments in the space nuclear field and presented their views on how increased application of nuclear technologies could fundamentally transform the ways in which both crewed and uncrewed space missions are carried out.

Three teams have been picked to design a fission surface power system that NASA could deploy on the moon by the end of the decade, NASA and Idaho National Laboratory announced today. A fission surface power project sponsored by NASA in collaboration with the Department of Energy and INL is targeting the demonstration of a 40-kWe reactor built to operate for at least 10 years on the moon, enabling lunar exploration under NASA’s Artemis program. Twelve-month contracts valued at $5 million each are going to Lockheed Martin (partnered with BWX Technologies and Creare), Westinghouse (partnered with Aerojet Rocketdyne), and IX (a joint venture of Intuitive Machines and X-energy, partnered with Maxar and Boeing).

NASA and Idaho National Laboratory have just opened a competitive solicitation for U.S. nuclear and space industry leaders to develop innovative technologies for a fission surface power system that could be deployed on the surface of the moon by the end of the decade. Battelle Energy Alliance, the managing and operating contractor for INL, issued a request for proposals and announced the news on November 19. Proposals are due February 17.

In July 1969, the public’s attention was fixated on NASA’s Apollo 11 mission—a “giant leap for mankind” that was memorably marked by Neil Armstrong as he stepped onto the surface of the moon. This July, the possibilities of spaceflight are once again capturing the public’s imagination and news headlines. While NASA invests in nuclear propulsion research and development to stretch the limits of U.S. space missions, private companies Virgin Galactic and Blue Origin are stretching the definition of “astronaut” and proving they can offer a high-altitude thrill to paying customers.

A hot fire test of the core stage for NASA’s Space Launch System rocket at Stennis Space Center in Mississippi was not completed as planned. The SLS is the vehicle meant to propel a crewed mission to the moon in 2024. Source: NASA Television

Among the executive orders President Trump issued during his last weeks in office was “Promoting Small Modular Reactors for National Defense and Space Exploration,” which builds on the Space Policy Directives published during his term. The order, issued on January 12, calls for actions within the next six months by NASA and the Department of Defense (DOD), together with the Department of Energy and other federal entities. Whether the Biden administration will retain some, all, or none of the specific goals of the Trump administration’s space nuclear policy remains to be seen, but one thing is very clear: If deep space exploration remains a priority, nuclear-powered and -propelled spacecraft will be needed.

The prospects for near-term deployment of nuclear propulsion and power systems in space improved during Trump’s presidency. However, Trump left office days after a hot fire test of NASA’s Space Launch System (SLS) rocket did not go as planned. The SLS rocket is meant to propel crewed missions to the moon in 2024 and to enable a series of long-duration lunar missions that could be powered by small lunar reactor installations. The test on January 16 of four engines that were supposed to fire for over eight minutes was automatically aborted after one minute, casting some doubt that a planned November 2021 Artemis I mission can go ahead on schedule.

An artist's concept of a fission power system on the lunar surface. Image: NASA

A national strategy for the responsible and effective use of space nuclear power and propulsion (SNPP)—Space Policy Directive-6 (SPD-6)—was released by the White House on December 16 as a presidential memorandum.

Space nuclear systems include radioisotope power systems and nuclear reactors used for power, heating, or propulsion. Nuclear energy can produce more power at lower mass and volume compared to other energy sources and can shorten transit times for crewed and robotic spacecraft, thereby reducing radiation exposure in harsh space environments. SPD-6 establishes a road map for getting space nuclear systems into service and sets up high-level goals, principles, and federal agencies’ roles and responsibilities.