Advanced propulsion researchers at NASA say they are a step closer to solving the challenge of safely sending human explorers to Mars and other solar system destinations using nuclear thermal rockets capable of propelling missions to the Red Planet and beyond.
NASA researchers are using an innovative test facility at the Marshall Space Flight Centre in Huntsville, Alabama, that enables them to use non-nuclear materials to simulate nuclear thermal rocket fuels.
NASA said the Nuclear Cryogenic Propulsion Stage team is tackling a three-year project to demonstrate the viability of nuclear propulsion system technologies.
A nuclear rocket engine uses a nuclear reactor to heat hydrogen to very high temperatures, which expands through a nozzle to generate thrust. Nuclear rocket engines generate higher thrust and are more than twice as efficient as conventional chemical rocket engines, NASA said.
The team recently used Marshall’s Nuclear Thermal Rocket Element Environmental Simulator, or NTREES, to perform realistic, non-nuclear testing of various materials for nuclear thermal rocket fuel elements, NASA said.
In an actual reactor, the fuel elements would contain uranium, but no radioactive materials are used during the NTREES tests. Among the fuel options are a graphite composite and a “cermet” composite – a blend of ceramics and metals. Both materials were investigated in previous NASA and US Department of Energy research efforts.
Nuclear-powered rocket concepts are not new. The US carried out studies and significant ground testing from 1955 to 1973 to determine the viability of nuclear propulsion systems, but stopped testing when plans for a crewed Mars mission were deferred.
The NTREES facility is designed to test fuel elements and materials in hot flowing hydrogen, reaching pressures up to 70 times greater than atmospheric pressure and temperatures of more than 2,700 degrees Celsius – conditions that simulate space-based nuclear propulsion systems to provide baseline data critical to the research team.
“This is vital testing, helping us reduce risks and costs associated with advanced propulsion technologies and ensuring excellent performance and results as we progress toward further system development and testing,” said Mike Houts, project manager for nuclear systems at Marshall.
A first-generation nuclear cryogenic propulsion system could propel human explorers to Mars more efficiently than conventional spacecraft, reducing crews’ exposure to harmful space radiation and other effects of long-term space missions. It could also transport heavy cargo and science payloads.
NASA said further development and use of a first-generation nuclear system could also provide the foundation for developing extremely advanced propulsion technologies and systems in the future – ones that could take human crews even further into the solar system.