NASA has ambitious plans to send crewed missions to Mars, but the journey currently takes several months to years. Nuclear thermal propulsion could be the game-changer, slashing the travel time by half. This article explores the incredible potential of this technology and the challenges researchers face in designing the reactors that would power these revolutionary rockets.
Trying to get nuclear fission to help us explore space
The trip to Mars is a long one; the distance between Earth and Mars ranges from 40 million miles (65 million kilometers) to 140 million miles (225 million kilometers), depending on where the planets are in their orbits when travelers set out, and it generally takes several months or even years using traditional chemical rocket fuel. However, a second technology—nuclear thermal propulsion (NTP)—promises to slash that journey time down to anywhere from 90 days to six months.
Nuclear thermal propulsion and fission go hand in hand because using nuclear fission, or splitting atoms to free an extraordinary amount of energy. That energy is then used to quickly heat a propellant — generally hydrogen — that shoots out the back of a rocket nozzle and creates thrust. It is more powerful and more efficient, so this type of system has a higher specific impulse (how efficiently the propellant used), around two times the value from conventional chemical rockets.
NASA and the Defense Advanced Research Projects Agency’s (DARPA) NTP technology efforts are ongoing with the goal of developing a flight demonstration routing on a spacecraft by 2027. It seeks a crewed mission to Mars that would take just four months, not six, to send astronauts out into deep space at unprecedented speeds and with an eye on the future of human presence there.
Nuclear Thermal Propulsion Reactor Design Challenges and Solutions
It may sound cool in theory that these nuclear atomic rockets would power are rocket to the red planet but it is not an easy task at all designing a reactor. A major challenge arose from deployment of a type of nuclear fuel — high-assay, low-enriched uranium (HALEU) — unsuitable for commercial light and small reactor applications.
Historically, NTP designs had used highly enriched uranium which are no longer in use due to nuclear proliferation concerns. Since HALEU has weaker material to fission off, the rockets must carry a heavier load of fuel and overall engine weight increases with this type of fuel. Scientists are looking into different materials and designs that use HALEU more efficiently in order to combat this problem.
Another important consideration is that the reactor can be turned on and off, as well as maneuvering without any difficulties throughout the mission. Achieving this demands the generation of sophisticated computational models and simulations to study tough physics exhibited by such engines under different circumstances.
Role of Researchers Advancing Nuclear Thermal Propulsion Technology
The nuclear thermal propulsion system models and simulations we are developing in my research group as an associate professor of nuclear engineering at Georgia Tech are specifically for the purpose of advancing the designs who said?
We’re aiming to help design the nuclear thermal propulsion engine that will one day carry humans to Mars — and we’ve got a plan to make it happen. To make this technology more broadly accessible — and ultimately commercially viable — we are developing new computational tools that can simulate activation, deactivation and operation of molten salt reactors without needing to use an impractical amount of computing power.
If we can gain a better understanding of how these complex reactors function, then perhaps we may one day be able to build the standalone control systems that actually fly and operate the nuclear thermal propulsion engines. This isn’t research solely for the sake of academia — it’s a labor of love that could help shape the course of space exploration in years to come.
