How Does a Nuclear Thermal Propulsion Rocket Work?

NASA is advancing nuclear power and propulsion in space to accomplish new national space objectives. This has put a new spotlight on nuclear thermal propulsion (NTP). NTP systems work by pumping a liquid propellant, most likely hydrogen, through a reactor core. Uranium atoms split apart inside the core and release heat through fission. This physical process heats up the propellant and converts it to a gas, which is expanded through a nozzle to produce thrust. NTP rockets are more energy dense than chemical rockets and twice as efficient. NTP is not new. It was studied by NASA and the Atomic Energy Commission (now the U.S. Department of Energy) during the 1960s as part of the Nuclear Engine for Rocket Vehicle Application program. During this time, Los Alamos National Laboratory scientists helped successfully build and test a number of nuclear rockets that current NTP designs are based off of today. Although the program ended in 1972, research continued to improve the basic design, materials and fuels used for NTP systems. Courtesy of the U.S. Department of Energy.