NASA plans to send crewed missions to Mars over the next decade – but the 140 million-mile (225 million-kilometer) journey to the red planet could take several months to years round trip.
This relatively long transit time is a result of the use of traditional chemical rocket fuel. An alternative technology to the chemically propelled rockets the agency develops now is called nuclear thermal propulsion, which uses nuclear fission and could one day power a rocket that makes the trip in just half the time.
