This is something big.
NASA and DARPA to test first nuclear rocket in earth orbit.
They are planning an in space demonstration of nuclear thermal propulsion under the DRACO program in early 2026. The system uses uranium fission to heat liquid hydrogen propellant, producing thrust with a specific impulse of roughly ~900 seconds, nearly double the efficiency of conventional chemical rockets, which peak near 450 seconds. The test is designed to validate reactor operation in orbit, with the nuclear system remaining inactive during launch.
This capability could reduce Mars transit times by ~25%, lowering astronaut exposure to radiation and enabling larger payloads and more flexible mission architectures. However, the program must navigate stringent nuclear safety requirements, complex reactor engineering and political oversight. If successful, DRACO would mark the first operation of a nuclear rocket in space, reviving concepts last explored during the NERVA era, this time with a clear focus on crewed missions to Mars and deeper space exploration.