NASA is sending a fission-powered spacecraft past Mars in 2028

Signals Inbox·August 31, 2026·SpaceTech

NASA plans to launch Space Reactor-1 Freedom toward Mars in 2028, using a fission reactor to power nuclear-electric propulsion beyond Earth orbit. The mission is a pathfinder rather than a crewed Mars ship, but it would move space nuclear propulsion from decades of studies into an actual interplanetary flight.

Q1What is NASA officially planning?

NASA's official mission page says SR-1 Freedom will target a 2028 launch and a 2029 Mars flyby while demonstrating nuclear-electric propulsion in deep space.

Q2Is this a nuclear rocket engine?

Not in the usual sense. The reactor produces electricity, which powers electric propulsion. That is different from nuclear-thermal systems that heat propellant directly inside a reactor.

Q3Why use fission in deep space?

Solar power gets weaker farther from the Sun and can be unreliable in permanently shadowed locations. Fission provides steady power independent of sunlight, which matters for long missions and future surface systems.

Q4What makes 2028 meaningful?

NASA says no spacecraft has used a fission reactor for propulsion beyond Earth orbit. A successful Mars pathfinder would turn space nuclear power from a recurring roadmap item into flight heritage.