NASA's nuclear Mars ship SR-1 Freedom firms up its power module for a late-2028 launch

NASA said on October 20 that it and its partners have agreed "key contract actions" to speed up development of Space Reactor-1 (SR-1) Freedom, which the agency describes as the first fission-powered spacecraft to travel beyond Earth orbit (confirmed, NASA). The update centres on the spacecraft's nuclear power module, and NASA says the mission remains on track for a late-2028 launch.

What happened

• Power conversion: Sierra Lobo Inc. will provide the nuclear power module's closed Brayton cycle power conversion system, which turns the reactor's heat into electricity for the spacecraft and its electric propulsion. The work falls under NASA Glenn Research Center's Space Flight Systems Development and Operations Contract III, awarded in 2024 (confirmed, NASA). NASA did not give a contract value in the announcement.
• Reactor: the fission reactor itself is being designed and developed by the Department of Energy's Idaho National Laboratory (confirmed, NASA).
• Safety: the reactor will stay inactive until the spacecraft has left Earth orbit, and the program runs interagency safety reviews under a NASA chief safety officer (confirmed, NASA).
• Mission: SR-1 Freedom will demonstrate nuclear electric propulsion in deep space and deliver SkyFall, a team of three Mars helicopters evolved from the Ingenuity design, to collect science data and help identify potential water sources (confirmed, NASA).

"These contract actions not only reduce technical risk and help us maintain momentum toward our 2028 launch, but they also strengthen collaboration across our partners," said Steve Sinacore, SR-1 Freedom program director (NASA).

Why it matters for space investors

Space nuclear power is moving from studies to flight hardware. NASA ties SR-1 Freedom directly to its lunar plans: the same class of fission systems is meant to keep its Moon Base running through lunar night and in places where solar power is not enough (confirmed, NASA). That makes reactor, power conversion and electric propulsion suppliers a growing niche inside NASA's exploration budget, alongside the Moon Base rover work the agency also updated this week.

For public markets, the announcement names no listed company: the power conversion work goes to Sierra Lobo and the reactor comes from a national laboratory. The near-term signal is schedule. A slip of the late-2028 date would be the first thing to watch. Track upcoming missions on our launch calendar and recent Mars news such as JAXA's MMX launch to Phobos. Not financial advice.

Sources

• NASA: NASA's SR-1 Freedom advances with progress on nuclear power module (Oct. 20, 2026)
• NASA: Space Reactor-1 Freedom mission page