NASA and DARPA will build a nuclear rocket by 2027

Artist concept of Demonstration for Rocket to Agile Cislunar Operations (DRACO) spacecraft, which will demonstrate a nuclear thermal rocket engine. Nuclear thermal propulsion technology could be used for future NASA crewed missions to Mars.
Artist concept of Demonstration for Rocket to Agile Cislunar Operations (DRACO) spacecraft, which will demonstrate a nuclear thermal rocket engine. Nuclear thermal propulsion technology could be used for future NASA crewed missions to Mars. (Image credit: DARPA)

NASA wants to design and demonstrate a working nuclear thermal rocket by 2027.

NASA Administrator Bill Nelson introduced the project on Tuesday (Jan. 24) during a presentation at the 2023 American Institute of Aeronautics and Astronautics (AIAA) SciTech Forum and Exposition held in National Harbor, Maryland. Nelson said that the agency will partner with the Pentagon's Defense Advanced Research Projects Agency (DARPA) in order to "develop and demonstrate advanced nuclear thermal propulsion, a revolutionary technology that will allow the United States to expand the possibilities for future human spaceflight missions."

Under the agreement, NASA will join DARPA's Demonstration Rocket for Agile Cislunar Operations, or DRACO, a program that began in 2021. The program seeks to develop a nuclear thermal engine that will be used by an experimental spacecraft designed by DARPA. DARPA will develop the nuclear reactor and engine for this nuclear rocket, which the agency and NASA hope to fly in an in-space demonstration as early as 2027. Nelson called the partnership an "exciting investment in the future of human space exploration" and "a major investment in getting to Mars."

Related: US military wants nuclear rocket ideas for missions near the moon

"DRACO will be a critical part of evaluating the technologies that will take us deeper into the solar system," NASA Deputy Administrator Pam Melroy said during the presentation. "Our intent is to lead and develop a blueprint for human exploration and sustained presence throughout the solar system. That is a very important goal. And we think that these advanced technologies will be a critical part of it." 

NASA and DARPA released an interagency agreement outlining the roles and responsibilities of each agency; the agreement grants NASA final authority over the nuclear thermal rocket engine's development and fabrication. However, the agreement grants DARPA authority over the "experimental NTR vehicle (X-NTRV)," the spacecraft that will be powered by the planned nuclear rocket engine, and DARPA will be responsible for operating and disposing of the X-NTRV in orbit. 

"NASA has a long history of collaborating with DARPA on projects that enable our respective missions, such as in-space servicing," Melroy said. "Expanding our partnership to nuclear propulsion will help drive forward NASA's goal to send humans to Mars."

This vision for a nuclear rocket dates back decades. NASA's Nuclear Engine for Rocket Vehicle Application, or NERVA program, sought to launch a crewed Mars mission in 1979 powered by a nuclear rocket. The program was canceled in 1972 due to budget cuts and worries of escalating the Cold War. 

Sending humans to Mars has become one of the primary spaceflight goals of government space agencies and private spaceflight firms alike. NASA's Artemis program is part of the agency's "Moon to Mars" vision that will leverage what NASA will learn from its planned lunar exploration to work toward establishing a human presence on the Red Planet

SpaceX, meanwhile, says it will soon launch orbital flight of its Starship vehicle that the company plans on eventually landing on Mars; other private space companies are working to beat that goal.

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Brett Tingley
Managing Editor, Space.com

Brett is curious about emerging aerospace technologies, alternative launch concepts, military space developments and uncrewed aircraft systems. Brett's work has appeared on Scientific American, The War Zone, Popular Science, the History Channel, Science Discovery and more. Brett has English degrees from Clemson University and the University of North Carolina at Charlotte. In his free time, Brett enjoys skywatching throughout the dark skies of the Appalachian mountains.

  • newtons_laws
    Great news! If NASA is serious about a crewed mission to Mars then a nuclear thermal rocket has obvious advantages, principally reduced journey times.
    Reply
  • billslugg
    Yes, nuclear thermal is essential to reduced travel time to Mars. Cosmic radiation damage to humans is a huge issue. Problem is, there will be a public outcry like we've never seen when people find out they plan to launch a nuclear reactor overhead. I doubt they'll get away with it.
    Reply
  • newtons_laws
    billslugg said:
    Yes, nuclear thermal is essential to reduced travel time to Mars. Cosmic radiation damage to humans is a huge issue. Problem is, there will be a public outcry like we've never seen when people find out they plan to launch a nuclear reactor overhead. I doubt they'll get away with it.

    Any outcry will be due to ignorance. As the reactor is only started for the first time once it's safely in orbit having been launched on a conventional chemical rocket the amount of radioactivity in the uranium fuel at launch is much less than that of the radio-isotope thermal generators (RTGs) already safely launched into Space on many occasions.
    Reply
  • Classical Motion
    What do you mean by nuclear thermal?
    Reply
  • billslugg
    Nuclear reactor core creates vast amounts of heat, liquid hydrogen is introduced as a coolant, gassifies, disassociates and is ejected at high velocity out through a nozzle. It only has one tenth the thrust to mass ratio as a chemical rocket thus cannot be used to lift off from Earth, but in outer space its mass doesn't matter. The efficiency is about twice that of chemical rockets. It would halve the time needed to get to Mars.
    Reply
  • Classical Motion
    Thank you billslugg. So they accelerate half way and decelerate the other half? Some were saying 45 days? To Mars?
    Reply
  • DocDrew
    newtons_laws said:
    Great news! If NASA is serious about a crewed mission to Mars then a nuclear thermal rocket has obvious advantages, principally reduced journey times.
    Big, Big Question for this.

    Where will we get the Pu238 that will be the probable fuel?
    Russia or China?

    All our plants at Hanford and Savanah River closed DECADES ago.
    Reply
  • mchargmg
    DocDrew said:
    Big, Big Question for this.

    Where will we get the Pu238 that will be the probable fuel?
    Russia or China?

    All our plants at Hanford and Savanah River closed DECADES ago.
    Apparently the design is similar to the old NERVA design, using low enriched uranium (see Nuclear Newswire ).
    Reply
  • billslugg
    Classical Motion said:
    Thank you billslugg. So they accelerate half way and decelerate the other half? Some were saying 45 days? To Mars?
    Yes, some are saying 45 days to Mars. I can't find anywhere how long the burns are.
    Reply
  • newtons_laws
    DocDrew said:
    Big, Big Question for this.

    Where will we get the Pu238 that will be the probable fuel?
    Russia or China?

    All our plants at Hanford and Savanah Riverocket reactors use r closed DECADES ago.


    Pu238 will definitely not be used, it's a very powerful alpha emitter and the intense heat it produces (in its pure form it glows dull red hot) makes it ideal for use in radio-isotope thermal generators (RTGs) as used on deep space probes and the Curiosity and Perseverance Mars rovers. It is not a reactor fuel, the proposed new nuclear thermal rocket reactor designs use relatively low enriched Uranium fuel i.e much less than 20% U235, typically about 5%, the rest being U238. The designs successfully tested in the 1960s e.g NERVA used highly enriched uranium, but highly enriched Uranium has to be closely guarded as it is a proliferation risk (if diverted into the wrong hands you can use it to make an atomic bomb). So low enrichment Uranium fuel is now preferred as it doesn't pose that problem. https://www.energy.gov/ne/articles/6-things-you-should-know-about-nuclear-thermal-propulsion
    Reply