NASA and Darpa are currently working on a new type of “nuclear-thermal” rocket booster. Agencies hope to show a demo of the first prototype by 2027.
© U.S. Department of Energy
The idea of creating rockets propelled by nuclear energy seems straight out of the 1960s, and for good reason: the United States Atomic Energy Commission, which has since merged into the United States Department of Energy, has already built and tested prototypes of such rocket engines.
These were based on nuclear fission and used low-enriched uranium. There are, however, obvious reasons why the project greatly reduced its ambitions as early as 1972. Indeed, the designs of the time involved significant releases of radioactive materials into the environment.
NASA and Darpa reinterested in nuclear rockets
And as always arises both the increased risk of dispersion of hazardous materials in the event of an accident at various stages of takeoff – as well as the dose of radiation potentially received by the occupants of rockets equipped with such nuclear propulsion systems. In short, the technology of the 1960s and 1970s would never have made it possible to arrive at sufficiently secure functional systems.
And given the space ambitions of the time, bringing the development of such types of systems to completion was far from inevitable. But in 2023, the prospect of exploring and colonizing Mars is a game-changer. It is necessary to prepare for long missions and therefore reducing the duration of transit should make it possible to reduce the volume of supplies and equipment that must be transported to anticipate all scenarios.
In concrete terms, NASA and Darpa are aiming for transport times divided by four compared to transit between Earth and Mars based on conventional propulsion technologies. In a press release, the agencies confirm the restart of the development of nuclear rocket boosters. The agencies will “demonstrate their advanced nuclear thermal propulsion technology as early as 2027”.
And add that with the help of this technology “astronauts will be able to travel to and from deep space faster which is a major capability for manned missions to Mars”. Additionally, the US government has validated new designs for small modular nuclear reactors capable of delivering power to these distant worlds.
The chosen design is a modular concept designed by the startup NuScale: we are talking about modules with a power of 50 megawatts each and a reduced size allowing them to be launched on rockets. It remains to be seen what guarantees the designers of these systems can provide against catastrophic accidents, such as the accidental explosion of a rocket example while it is still in the Earth’s atmosphere.