SR-1 Freedom Mission Could Fulfill NASA's 70-Year Dream of Putting Nuclear Reactors in Space

Just a few days ago, NASA announced a bold plan to send a brand-new vehicle to Mars in 2028. It will carry the planned Skyfall payload, full of Ingenuity-class fliers, which should greatly increase scientists' understanding of the Red Planet's composition—but it's the ship's power and propulsion system that are truly exciting.

Called the SR-1 Freedom, this latest spacecraft will use an electric propulsion system originally intended for use repositioning asteroids, then repurposed for a canceled lunar space station called Gateway, and now repurposed again for Mars.

In terms of propulsion, it's essentially just a greatly scaled-up version of an ion thruster. In classical ion thrusters, the type on many current satellites, solar panels generate a small current of electricity, which is used to create a weak electromagnetic field inside an open reaction chamber. A solid puck of fuel slowly diffuses ions into this chamber ...