Bethesda, Maryland-based Lockheed Martin has won a $500 million contract from the Defense Advanced Research Projects Agency to develop a nuclear-powered spacecraft that could conquer two of interplanetary space travel’s biggest challenges: speed and running out of gas.

Under the contract, Lockheed will both develop and demonstrate the spacecraft under a project called Demonstration Rocket for Agile Cislunar Operations. Lockheed said the nuclear-powered propulsion technology would mean much more powerful and efficient propulsion that is two to five-times more efficient, and would allow spacecraft to travel faster and farther.

DARPA partnered with NASA on the project. Lockheed said the first in-space flight demonstration of the nuclear thermal rocket engine vehicle will take place no later than 2027.

“These more powerful and efficient nuclear thermal propulsion systems can provide faster transit times between destinations. Reducing transit time is vital for human missions to Mars to limit a crew’s exposure to radiation,” said Kirk Shireman, vice president of Lunar Exploration Campaigns at Lockheed Martin Space.

“With more speed, agility and maneuverability, nuclear thermal propulsion also has many national security applications for cislunar space.”

Space missions are notoriously vulnerable to launchpad and post-launch failures, so Lockheed’s nuclear-powered reactor would not be turned on until the spacecraft has reached a nuclear-safe orbit.

Lockheed said its nuclear thermal propulsion technology will use a nuclear reactor to quickly heat hydrogen propellant to very high temperatures, then funnel that gas through an engine nozzle to create a powerful thrust, with a fission-based reactor using high-assay low-enriched uranium to convert the cryogenic hydrogen into an extremely hot pressurized gas.

The nuclear-powered reactor will be built in Lynchburg, Virginia, by Lockheed partner BWX Technologies.

“In the past several years, BWXT has been maturing its nuclear thermal propulsion fuel and design, and we are excited to further expand into space with our ability to deliver nuclear products and capabilities to the U.S. Government,” said Joe Miller, president of BWXT Advanced Technologies LLC.

Lockheed is currently the prime contractor on NASA’s Orion spacecraft program and its Artemis program for the first human missions to Mars.