NASA announced on Tuesday that it will pause development of the Gateway lunar space station and repurpose its Power and Propulsion Element for SR-1 Freedom, a nuclear-electric propulsion demonstration mission to Mars launching before the end of 2028. The spacecraft will carry Skyfall helicopters to scout subsurface water ice and landing sites. Officials described the move as leveraging existing hardware to prove nuclear power in deep space.
NASA revealed its updated exploration roadmap during an all-day event at its headquarters in Washington on March 25, shifting focus from the Gateway lunar outpost to a Moon surface base, in line with the Trump administration's space policy. The agency has invested nearly $4.5 billion in Gateway since 2019, with components like the Power and Propulsion Element (PPE) under construction at Lanteris Space Systems in Palo Alto, California. This core module, originally solar-powered with three 12-kilowatt engines and four 6-kilowatt thrusters, will now incorporate a uranium-fueled fission reactor producing about 20 kilowatts—20 times more than current deep-space nuclear generators like those on Mars rovers or Voyager probes. NASA Administrator Jared Isaacman stated, “We will launch the first-of-its-kind interplanetary mission called SR-1 Freedom before the end of 2028, demonstrating fission power and the extraordinary capabilities to move mass efficiently in space.” The mission aims to prove the US can build, launch, and operate a nuclear propulsion system, using nuclear-electric engines for higher efficiency than chemical rockets. Steve Sinacore, NASA’s program executive for space reactors, emphasized, “The lack of an operational space nuclear reactor is not a technology problem, it’s an execution problem.” Launch targets the December 2028 Mars window, with design complete by June 2026 and assembly starting in early 2028. SR-1 Freedom will also deploy three Ingenuity-based helicopters, named Skyfall, via an entry capsule to scan Martian terrain for subsurface water ice using cameras and ground-penetrating radars. This follows cancellations of prior nuclear efforts like Project Prometheus and DRACO, amid past spending of billions with limited success—the last US space reactor, SNAP-10A, flew in 1965. Multiple agencies, including the Department of Energy, must approve the radioactive launch, potentially using SpaceX’s Falcon Heavy.
