Nuclear reactor bound for Mars: NASA moves ahead with SR-1 Freedom spacecraft

NASA is making progress on its Space Reactor-1 (SR-1) Freedom project. The agency said on Tuesday that it and its partners have agreed key contract actions intended to speed development and reduce technical risk. SR-1 Freedom is to become the first fission-powered spacecraft to travel beyond Earth orbit. On its way to Mars, it is meant to demonstrate nuclear electric propulsion in deep space. Launch is targeted for late 2028. Program director Steve Sinacore said the actions "reduce technical risk and help us maintain momentum toward our 2028 launch."

At its heart is the power module at the end of a boom. It consists of a reactor that generates heat through fission and a power conversion system that turns that heat into electricity for the spacecraft's systems and its electric propulsion. The reactor is being designed and developed by the US Department of Energy's Idaho National Laboratory. The closed Brayton cycle conversion system will be supplied by Sierra Lobo under a contract at the Glenn Research Center in Cleveland. The reactor is to stay inactive until the spacecraft has left Earth orbit.

The spacecraft will carry the SkyFall science mission with three Mars helicopters evolved from the Ingenuity design. They are to collect data, scout potential exploration zones and look for possible water sources. NASA also points to interagency safety reviews and continuous oversight by a chief safety officer. In the long term, such fission systems are meant to keep a Moon base running through periods of darkness and in places where solar power alone is not enough.