Nuclear thermal engine concepts for deep space exploration
Three reactor design concept proposals for a nuclear thermal propulsion system for deep space missions have been selected by the US National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE). The reactor will be a critical component of a nuclear thermal engine, which would utilise high-assay low-enriched uranium fuel.
Idaho National Laboratory (INL) will award 12-month contracts to three consortia to each produce a conceptual reactor design that could support future deep space mission needs. These are:
- BWX Technologies (with Lockheed Martin);
- General Atomics Electromagnetic Systems (with X-energy and Aerojet Rocketdyne); and
- Ultra Safe Nuclear Technologies (with Ultra Safe Nuclear Corporation (USNC), GE Hitachi Nuclear Energy, GE Research, Framatome and Materion).
Each contract is valued at about USD5 million.
Nuclear thermal engine
Nuclear propulsion provides greater propellant efficiency as compared with chemical rockets. It is a potential technology for crew and cargo missions to Mars. And of course the science missions to the outer solar system. This enables faster and more robust missions.
Jim Reuter, associate administrator for NASA’s Space Technology Mission Directorate, said: “These design contracts are an important step towards tangible reactor hardware. That could one day propel new missions and exciting discoveries.”
Stephen Johnson, national technical director for space nuclear power and director of the Space Nuclear Power and Isotope Technologies Division at INL, added:. “Our national laboratories, working in partnership with industry. We bring unparalleled expertise and capabilities to assist NASA. We solves highly complex challenges that come with nuclear power and propulsion.”
Strategy of development
The US Administration in December 2020 announced a national strategy to ensure the development and use of space nuclear power and propulsion systems, including nuclear thermal propulsion (NTP) systems, which can power spacecraft for missions where alternative power sources are inadequate.
In April, the US Defense Advanced Research Projects Agency awarded contracts for the first phase of its Demonstration Rocket for Agile Cislunar Operations programme to demonstrate an NTP system above low Earth orbit in 2025. General Atomics will carry out reactor development work, while Blue Origin and Lockheed Martin will develop spacecraft concept designs.
NASA said it is also maturing a fission surface power system for use on the Moon and Mars. It intends to partner with the DOE and INL to release a request for proposals that asks industry for preliminary designs of a 10-kilowatt class system that NASA could demonstrate on the lunar surface. Maturing fission surface power can also help inform nuclear electric propulsion systems, another candidate propulsion technology, for distant destinations.