NASA and DARPA, the Pentagon’s semi-secret experimental technology agency, awarded a joint contract to Lockheed Martin to produce the first nuclear thermal rocket engine that could power a manmade craft between planets, the Washington Post reports.
A nuclear thermal engine uses nuclear fission to heat hydrogen, which is then shot through nozzles to propel the craft. The power system has significant benefits over traditional liquid-fuel or chemical rockets, such as having a longer operational time as well as the potential to develop higher velocities. For safety, the reactor would not be initiated until the craft was in space.
A craft powered by such an engine could be used for repeated interplanetary trips over years using an orbiting platform, like the International Space Station, as a base because it would not require refueling on the ground. The half-billion dollar contract requires a first flight of the engine by 2027, which DARPA notes will allow for “larger payloads into farther locations in cislunar space — the volume of space between the Earth and the moon.”