NASA and DARPA have unveiled plans to test a novel nuclear thermal rocket engine—a technology capable of tripling propulsion efficiency compared to conventional chemical rockets. The project, dubbed DRACO, hinges on recent advances in nuclear fuel, with General Atomics reporting significant progress in testing fuel elements capable of withstanding the extreme conditions of an Nuclear Thermal Propulsion (NTP) reactor.
According to a NASA press release, DRACO—short for “Demonstration Rocket for Agile Cislunar Operations”—was originally slated to integrate a nuclear thermal rocket engine into a test spacecraft by 2027, promising up to three times the propulsion efficiency of conventional chemical rockets and shorter Mars transit times. (Some assessments have estimated that a nuclear thermal rocket offers two to five times more efficiency than chemical rockets.) Yet updated assessments indicate that the 2027 demonstration is now on hold as the DARPA-NASA team addresses challenges inherent in safely ground-testing and integrating a nuclear reactor—a feat not attempted in over 60 years, as Aviation Week noted. The program remains committed to an eventual in-orbit demonstration once these technical and safety hurdles are resolved.
Meanwhile, in separate tests conducted at NASA’s Marshall Space Flight Center under a contract managed by Battelle Energy Alliance and Idaho National Laboratory, GA‑EMS verified its nuclear fuel’s resilience under rapid thermal cycling and high-temperature hydrogen flow—key factors for sustaining high thrust and efficiency in space. Meanwhile, in a separate announcement from General Atomics Electromagnetic Systems (GA-EMS), the company reported major progress in testing nuclear fuel elements designed for the extreme conditions inside an NTP reactor.
We’ve also conducted tests in a non-hydrogen environment at our GA-EMS laboratory, which confirmed the fuel performed exceptionally well at temperatures up to 3000 K, which would enable the NTP system to be two-to-three times more efficient than conventional chemical rocket engines.
In addition to General Atomics, BWXT is responsible for designing and manufacturing the reactor and its fuel (using HALEU), also ensuring that all subsystems meet the rigorous performance and safety requirements.
Nuclear-powered spacecraft have become something of a trend in recent years, with Lockheed Martin emerging as a key player in U.S. initiatives. The company is involved in several high-profile projects, including the DRACO Nuclear Thermal Propulsion (NTP) system, which aims for a 2027 orbital demonstration in collaboration with DARPA and NASA, and the JETSON nuclear electric propulsion (NEP) project for the U.S. Air Force. The latter utilizes Stirling engines to generate electricity for deep-space missions.
Meanwhile, Europe’s ESA is advancing its own NEP ambitions through the RocketRoll project. A consortium led by Tractebel has completed a conceptual design for a demonstrator spacecraft targeting a 2035 launch. This system could reduce Mars transit times by 60% compared to conventional chemical rockets while also enabling missions beyond Jupiter’s orbit.
According to data released by General Atomics Electromagnetic Systems (GA-EMS), the company subjected its nuclear fuel samples to six rapid thermal cycles at NASA’s Marshall Space Flight Center test facilities, heating them to 2600 K (approximately 4220° F) under hot hydrogen flow. Each cycle maintained this extreme temperature for 20 minutes to simulate the harsh conditions encountered by a nuclear thermal propulsion (NTP) reactor in space. GA-EMS also reported that additional testing in non-hydrogen environments exposed the fuel to temperatures as high as 3000 K, demonstrating the material’s durability far beyond the operational thresholds required to achieve two to three times the efficiency of traditional chemical rockets.
Meanwhile, DARPA, which oversees the DRACO program, is integrating GA-EMS’s fuel innovations with next-generation reactor technology and spacecraft architecture. If current testing maintains or surpasses performance benchmarks, the resulting nuclear thermal rocket could dramatically shorten Mars transit times, minimize mission risks, and enhance deep-space operational capacity.
