The U.S. Department of Defense's Defense Innovation Unit (DIU) has announced two prototype contracts on May 17 "to demonstrate the next generation of nuclear propulsion and power capability for spacecraft."
The ultimate goal, according to DIU officials, is an orbital flight demonstration in 2027.
It's part of the U.S. military's urgent focus on cislunar activities in order to keep an eye on commercial and government activities that will ramp up there in the next decades, such as the worldwide NASA-led Artemis program, which aims to land people on the moon in the 2020s.
Two companies, Ultra Safe Nuclear and Avalanche Energy, were awarded contracts to demonstrate nuclear propulsion and power capabilities for small spacecraft operating in cislunar (Earth-moon) space.
The contract values were not disclosed in the release.
If all goes as planned, Ultra Safe Nuclear will show EmberCore, a charged nuclear radioisotope battery useful for propulsion and power.
"This 'next-gen' radioisotope system will be able to scale to 10 times higher power levels, compared to plutonium systems, and provide more than 1 million kilowatt-hours (kWh) of energy in just a few kilograms of fuel," DIU stated.
The Orbitron from Avalanche Energy aims to capture fusion ions in electrostatic fields, using a magnetron to hold electrons closer to their nuclei (atom cores) than is normally achievable.
"The resulting fusion burn then produces the energetic particles that generate either heat or electricity, which can power a high-efficiency propulsion system," DIU stated. "Compared to other fusion concepts, Orbitron devices are promising for space applications as they may be scaled down in size and enable their use as both a propulsion and power source. "
The Defense Advanced Research Projects Agency (DARPA) is another military entity interested in cislunar nuclear technology. On May 4, the group said that it is ready to proceed with a project to design, manufacture, and assemble a nuclear thermal rocket engine for an Earth orbit flight demonstration in 2026.
The proposals will help DARPA's Demonstration Rocket for Agile Cislunar Operations (DRACO) program create nuclear thermal propulsion (NTP) system for usage in Earth-moon orbit.
NTP generates thrust by heating hydrogen or other propellants in fission reactors and shooting them out of nozzles, resulting in a thrust-to-weight ratio 10,000 times higher than electric propulsion systems. DARPA officials wrote in a description of the DRACO program that it outperforms chemical rockets because the propulsion efficiency (specific impulse) of NTPs is two to five times higher.
