The US space agency has given money to fund a new concept that could, according to its proponents, cut the time it takes to travel to Mars by around a fifth. This would be no small step forward for human missions to the Red Planet, as one of the most pressing problems with Mars travel is that astronauts would be exposed to cosmic radiation for the entire seven to nine month journey, while their muscles and other organs could be severely damaged in zero gravity.
The Nuclear Thermal Propulsion and Nuclear Electric Propulsion, or NTP/NEP, concept could significantly shorten this most critical period for Mars travel by using a bimodal propulsion system that combines the two technologies, says Interesting Engineering.
Nuclear thermal propulsion uses a nuclear reactor to heat liquid hydrogen, which is converted into plasma and then passes through a funnel to generate thrust. Nuclear electric propulsion, on the other hand, uses the reactor to drive an ion engine based on the Hall effect, i.e. an electromagnetic field that ionises and accelerates the gases, generating thrust.
Ryan Gosse, who developed the concept and leads the University of Florida’s hypersonic systems development programme, has added a so-called wave rotor, which uses the pressure generated by heating liquid hydrogen to compress the reaction mass, making the engine even more efficient.
NASA is funding the development of the engine under the recently announced Innovative Advanced Concepts (NIAC) programme. As NIAC was looking for futuristic and innovative solutions, it also means that the creation of such an engine is a distant prospect, as indicated by the fact that the space agency has given a paltry $12 500 for the concept development, which is a tiny amount compared to its budget.
Of course, this does not mean that nuclear rocket engines will have to wait for decades, as there have been several promising developments in the field in recent years: the Ad Astra Rocket Company successfully tested the Vasimr VX-200SS ion engine in 2021, and Seattle-based Ultra Safe Nuclear Technologies delivered the designs for an NTP-type engine to NASA in 2020.