Scientists began theorising about the use of nuclear energy to power spaceflight as early as the 1940s. Beginning in the 1950s, the United States conducted ground tests in this area. Budget cuts and shifting priorities (such as a concentration on the Space Shuttle programme) forced NASA to terminate the project before any test flights could take place at the end of 1972.
Of course, there are concerns associated with NTP engines, such as the probable release of radioactive material into the environment if a breakdown occurs in the atmosphere or orbit. Nonetheless, NASA claims that the shorter transit times enabled by NTP engines might lessen human danger – they could cut trip durations to Mars by up to a fourth. Nuclear thermal rockets have the potential to be three times more efficient than traditional chemical propulsion techniques.
