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.”

Zeno Power, a developer of commercial radioisotope power systems (RPSs), announced on October 26 that it has completed the design, fabrication, and testing of its Z1 strontium-90 heat source. According to Zeno, they have tested the first commercially developed radioisotope heat source and reached a key milestone for Zeno to begin delivering RPSs to customers in 2025.

Ultra Safe Nuclear (USNC) announced on October 17 that it had been awarded a contract by NASA to develop and mature space nuclear thermal propulsion (NTP) systems to advance the nation’s cislunar capabilities. Under the contract, USNC says it will manufacture and test proprietary fuel and simultaneously collaborate with its commercial partner, Blue Origin, to mature the design of an NTP engine optimized for near-term civil science and cislunar missions.

Sometimes, even with decades of research and testing, a project never gets off the ground. That has been the case for U.S. nuclear thermal rockets—so far. Research began in the 1950s and peaked with a series of rigorous ground tests for NERVA—the Nuclear Engine for Rocket Vehicle Applications—before the program was canceled in 1973. Five decades on, this technology has yet to make it to the launchpad. But while mission priorities shift, the physics is solid: Fission-powered nuclear thermal rockets (NTRs) still offer two to five times greater efficiency than conventional rockets.

The Department of Energy recently shipped half a kilogram of plutonium oxide pellets from Oak Ridge National Laboratory to Los Alamos National Laboratory, the agency announced July 18, marking the largest such shipment since the DOE restarted domestic plutonium-238 production over a decade ago.

Really taking off during the pandemic, ANS’s online event programming remains very strong and continues to be a great resource for the nuclear community. This year alone, ANS has produced 14 different webinars—some of which are only available to members, with most available to the general public.

Westinghouse Electric Company says its eVinci microreactor technology is “100 percent factory built and assembled before it is shipped in a container to any location.” And “any location” is not restricted to planet Earth, given the company’s goal of sending a scaled-down version of eVinci to the lunar surface or on a mission to provide power in other space applications.

Zeno Power Systems was awarded a $30 million contract to build a radioisotope-powered satellite for the U.S. Air Force by 2025. According to a SpaceNews article announcing the development and quoting company cofounder and chief executive officer Tyler Bernstein, the four-year contract is a “strategic funding increase” (STRATFI) agreement that provides $15 million in government funds, matched by $15 million from private investors.

NASA and the Defense Advanced Research Projects Agency (DARPA) have announced they will collaborate on plans to launch and test DARPA’s Demonstration Rocket for Agile Cislunar Operations (DRACO). DARPA has already worked with private companies on the baseline design for a fission reactor and rocket engine—and the spacecraft that will serve as an in-orbit test stand—and has solicited proposals for the next phase of work. Now NASA is climbing on board, deepening its existing ties to DRACO’s work in nuclear thermal propulsion (NTP) technology—an “enabling capability” required for NASA to meet its Moon to Mars Objectives and send crewed missions to Mars. NASA and DARPA representatives announced the development at the American Institute of Aeronautics and Astronautics SciTech Forum in National Harbor, Md., on January 24.

A “resurgence of interest” in nuclear propulsion for space missions is described in a new article authored by science writer Jon Kelvey for the American Institute of Aeronautics and Astronautics’ (AIAA’s) Aerospace America website. The focus of Kelvey’s article is nuclear thermal propulsion (NTP), which, according to the Department of Energy, “could significantly reduce travel times and carry greater payloads than today’s top chemical rockets­—giving humans a great chance of exploring deep space.”

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.

General Atomics Electromagnetic Systems (GA-EMS) has completed the baseline design of a reactor and engine for a nuclear thermal propulsion (NTP) rocket and has successfully tested key reactor components under contract from the Defense Advanced Research Projects Agency (DARPA), the company announced on November 7. The work was performed under a Track A, Phase 1 contract for the Demonstration Rocket for Agile Cislunar Operations (DRACO) program; Phases 2 and 3 of DRACO could culminate in a demonstration of the nuclear-propelled spacecraft in cislunar space (the region between the Earth and the Moon) during fiscal year 2026.

Seeds from the joint laboratories of the International Atomic Energy Agency and the Food and Agriculture Organization of the United Nations (FAO) are onboard a Cygnus spacecraft launched from NASA’s Wallops Flight Facility in Virginia early on November 7. Now orbiting the Earth en route to the International Space Station, the seeds are part of a commercial resupply mission with a payload that includes resources to support more than 250 scientific investigations.

The Defense Innovation Unit (DIU), a Department of Defense organization focused on swiftly putting commercial technology to use in the U.S. military, has awarded contracts for two nuclear technologies—compact fusion and radioisotope heat—for spacecraft that could carry a high-power payload and freely maneuver in cislunar space. The objective is to accelerate ground and flight testing and launch a successful orbital prototype demonstration of each approach in 2027.

The Department of Defense wants to deploy spacecraft in cislunar space—the area between Earth and the moon’s orbit—with thrust and agility that only nuclear thermal propulsion (NTP) can provide. The Defense Advanced Research Projects Agency (DARPA), through its Demonstration Rocket for Agile Cislunar Operations (DRACO) program, is looking to private industry for the design, development, fabrication, assembly, and testing of a nuclear thermal rocket engine fueled with high-assay low-enriched uranium fuel to heat a liquid hydrogen propellant.

With three commercial teams under contract to produce reactor designs for nuclear thermal propulsion rockets that would use solid high-assay low-enriched uranium fuel to heat hydrogen propellant, NASA’s investment in nuclear thermal propulsion (NTP) has increased in recent years. But just as there is more than one way to fuel a terrestrial reactor, other fuels are under consideration for future NTP rocket engines.

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.

The U.S. Department of Defense is aiming to demonstrate a novel nuclear thermal propulsion (NTP) system above low Earth orbit by 2025. The Defense Advanced Research Projects Agency (DARPA) announced on April 12 that following a competitive solicitation process, it has awarded a contract to General Atomics Electromagnetic Systems (GA-EMS) for the design of the nuclear reactor that will power the Demonstration Rocket for Agile Cislunar Operations (DRACO). Blue Origin and Lockheed Martin will work on a parallel track to design a spacecraft tailor-made to demonstrate the NTP system.

NASA’s Mars 2020 Perseverance rover took its first drive on the surface of Mars on March 4, traversing 21.3 feet and executing a 150-degree turn in about 33 minutes. The drive was one part of an ongoing check and calibration of every system, subsystem, and instrument on Perseverance, which landed on Mars on February 18.

The NASA team has also verified the functionality of Perseverance’s instruments, deployed two wind sensors, and unstowed the rover’s 7-foot-long robotic arm for the first time, flexing each of its five joints over the course of two hours.

With relatively little fanfare, the functionality of Perseverance’s radioisotope thermoelectric generator (RTG)—assembled at Idaho National Laboratory and fueled by the decay of plutonium-238—is also being proved. It is reliably providing the power that Perseverance’s mechanical and communication systems require.