Project Orion: When NASA Wanted to Nuke Its Way to Mars

In 1958, physicist Freeman Dyson and a team at General Atomics proposed the most audacious spacecraft ever seriously designed: a vehicle propelled by sequential nuclear explosions. Project Orion promised to deliver payloads of thousands of tons to Mars in weeks, not months.

The physics worked. Small nuclear charges would be ejected from the rear of the craft and detonated against a massive pusher plate. The specific impulse achievable was orders of magnitude beyond chemical rockets. Early designs could have carried entire habitats to Mars.

Project Orion was killed not by engineering limitations but by the 1963 Partial Nuclear Test Ban Treaty, which prohibited nuclear explosions in space.

The spiritual descendants of Orion live on in BWXT's nuclear thermal propulsion work and in theoretical designs for nuclear pulse propulsion using fusion rather than fission. The underlying insight — that nuclear energy is the only technology capable of making interplanetary travel practical — remains as valid today as it was in 1958.