DARPA
Nearly three years ago, the US Department of Defense Advanced Research Projects Agency announced its intention to develop a flightable nuclear thermal propulsion system. The goal was to develop more responsive control of spacecraft in Earth orbit, lunar orbit, and everywhere in between, giving the military greater operational freedom in these areas.
The military agency called the program the Demonstration Rocket for Agile Sisluna Operations, or DRACO for short. The program consists of two of his developments, a nuclear fission reactor and the spacecraft that fly it. In 2021, DARPA gave him $22 million to General Atomics for nuclear reactors, and a smaller grant of $2.9 million to Lockheed Martin and $2.5 million to Blue Origin for spacecraft systems.
At the same time, NASA was beginning to realize that if it was serious about sending humans to Mars one day, it would be nice to have a faster, more fuel-efficient way to get there. A seminal report published in 2021 concluded that the only realistic path for space agencies to send humans to Mars in the coming decades is to use nuclear propulsion.
Nuclear thermal propulsion involves a rocket engine, in which a nuclear reactor replaces the combustion chamber and burns liquid hydrogen as fuel. The fuel required to reach Mars is significantly less than chemical propulsion, often less than 500 tons. This is useful for Mars missions, including some pre-missions to prepare cargo on Mars in advance.
So this week, NASA announced a partnership with a military agency to join the DRACO project.
“NASA, working with its long-term partner DARPA, plans to develop and demonstrate advanced nuclear thermal propulsion technology as early as 2027. With the help of this new technology, astronauts It will be able to get in and out of deep space faster than ever before, a key capability to prepare for manned missions to Mars.”
The US space agency does not provide direct funding at this time. However, its Space Technology Mission Directorate will lead the technological development of nuclear heat engines, a key component of spacecraft that harness energy from nuclear reactors. DARPA will continue to lead overall program development, including rocket systems integration and procurement.
Nuclear thermal propulsion has long been a goal of spaceflight advocates dating back to the days of German rocket scientist Werner von Braun and NASA’s project NERVA. These plans never came to fruition and the idea was put on the back burner for decades. This joint project is currently the most serious US effort to develop this technology. This has the added benefit of interest from the US Congress, which is pushing the space agency to get involved.
None of this will happen immediately. The technology is difficult and unproven, and of course there are regulatory issues with launching nuclear reactors into space. 2027 seems optimistic for demonstrations, and it’s unlikely that the technology will be used to send humans to Mars until at least the late 2030s.
But finally something is happening. That’s enough for now.
