A new nuclear-electric engine to reach Mars

NASA has approved the first research phase of a project under the Innovative Advanced Concepts (NIAC) programme to develop a new type of engine using dual nuclear thermal (NTP) and electric (NEP) propulsion that will drastically reduce travel time to Mars.

The aim is to launch astronauts in large spacecraft at high speed with minimal fuel usage, allowing interplanetary missions to be carried out in a very short time that avoids the effects of cosmic radiation and the lack of gravity, two of the problems of such long-distance travel.

NTP systems work on the basis of a nuclear reactor that transfers the heat of the reaction to a hydrogen gas propellant. This hydrogen, now at high temperatures, expands in the engine nozzle to propel the vehicle. The technology allows for high thrust but can also double the time the engine is active compared to the chemical engines used today.

The NEP engine, on the other hand, uses the nuclear reactor to generate electrical energy that is then used to ionise an inert gas propellant. Electromagnetic or electrostatic forces accelerate these gases, which are ejected from the nozzle and propel the vehicle.

NTP engines deliver high power for longer than chemical engines, but this period may be limited to about 900 seconds. In contrast, NEP engines deliver less powerful pulses but can be extended for more than two hours. The combined engine proposed by Ryan Gosse, an aerospace engineer at the University of Florida who came up with the idea, could generate the power of an NTP engine for even longer, between 1,400 and 2,000 seconds, and would also have an additional NEP cycle that would allow the pulse to continue (between 1,800 and 4,000 seconds).

Unlike other projects included in this programme, such as the engine that NASA announced in early January for the same purpose, this new system would enable spacecraft to reach Mars in 45 days and would not be limited to a mass of about one tonne.

Source: NASA Innovative Advanced Concepts (NIAC) Program