NASA and DARPA, plan to launch a nuclear vehicle into Earth‘s orbit by the end of 2025 or the beginning of 2026. The project, known as DRACO (Demonstration Rocket for Agile Cislunar Operations), aims to provide a test of nuclear thermal propulsion (NTP) in space. This potentially revolutionary technology could make it easier for humanity to reach Mars.
DRACO Project
DRACO will be developed and built by Lockheed Martin, as announced by the team members. “We will fly this demonstrator and gather a lot of data. We will inaugurate a new era for humanity in the field of space exploration” said Kirk Shireman, Vice President of Lockheed Martin’s Campaigns, during a press conference.
DRACO is not new. The U.S. Defense Advanced Research Projects Agency (DARPA) initiated the program in 2021, and NASA joined at the beginning of 2023. NASA’s involvement is not surprising at all. The agency’s interest in NTP technology dates back a long time. NASA aimed to launch a crewed mission to Mars aboard a nuclear-powered spacecraft by 1979. The program called NERVA (Nuclear Engine for Rocket Vehicle Application). However, NERVA was canceled in 1972.
NASA’s medium to long-term goal is Mars. American agency aims to send astronauts to Mars by the late 2030s or early 2040s. Even today, they consider nuclear thermal propulsion to be crucial for significantly reducing travel times.
NTP Engines
Nuclear vehicles carry small fission reactors. NTP engines release incredible amounts of heat that is transferred to a propellant gas. This expanding gas is channeled into space through a nozzle to create thrust. The process is quite different from that used by radioisotope thermoelectric generators (RTGs) aboard probes since the early days of the space age. RTGs do not provide propulsion. They harness the heat from radioactive decay to generate electricity, which powers the instruments.
In previous DRACO updates, DARPA and NASA stated their intention to launch the first nuclear demonstrator vehicle into space by 2027. However, that date might be brought forward. Shireman mentioned in the briefing that the current target launch window is the end of 2025 or the beginning of 2026. Other details confirm this accelerated timeline. Lockheed is collaborating with BWX Technologies, which will develop the nuclear reactor for the DRACO spacecraft and produce its HALEU fuel (high-assay, low-enriched uranium).
The spacecraft will be placed in a relatively high orbit around Earth, probably between 700 and 2,000 kilometers, according to team members during the briefing. From such altitudes, it will take at least 300 years before the DRACO demonstrator re-enters Earth’s atmosphere. This lengthy time frame ensures that all its nuclear fuel will be depleted.
Technical Challenges
The nuclear engine of the DRACO spacecraft will only be activated once it reaches orbit. During launch, it will be equipped with a “poison wire” a piece of metal that absorbs neutrons, preventing the chain reaction from starting. The system acts like control rods made of graphite in nuclear reactors. DRACO is expected to operate in orbit for several months. There won’t be any scientific instruments onboard. Only the functioning of its NTP engine will be evaluated, demonstrating that it can operate for extended periods in the space environment.
However, using that engine will also require keeping DRACO’s hydrogen (approximately 2,000 kilograms) super cold, which is no small feat. “Our limiting factor is how long we can maintain cryogenic hydrogen” stated Tabitha Dodson, DRACO Program Manager at DARPA. “This is as much a demonstration of in-orbit cryogenic liquid hydrogen storage as it is a demonstration of the nuclear thermal rocket engine”.
Dodson added that while the specifications of the spacecraft are still in development, it will primarily consist of the NTP engine system and a large tank to contain the hydrogen. The vehicle won’t require a heavy-lift rocket. It will be small enough to fit inside the payload fairing of a “standard” launcher like SpaceX‘s Falcon 9.