Tucked into the recent spending bill that was passed by Congress is a line item for $100 million for NASA to develop nuclear thermal rocket engines, according to a recent article in Space News. The space agency has dabbled in nuclear rockets off and on since the early 1960s. However, NASA plans to conduct a flight demonstration by 2024 is new.

As NASA noted, the space agency in conjunction with what was then the Atomic Energy Commission worked on a project called the Nuclear Engine for Rocket Vehicle Application (NERVA) program in the 1960s. The NERVA program tested various reactors and engines until the project was closed in 1972, once it became apparent that humans had stopped going to the moon and would not travel to Mars anytime soon.

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A nuclear thermal rocket superheats liquid hydrogen in a nuclear reactor and shoots the resulting plasma out a rocket nozzle. Nuclear Thermal Propulsion (NTP) is far more efficient than a chemical rocket, reducing flight times to destinations such as Mars and requiring less fuel. Astronauts would be subjected to less radiation and less time in microgravity using NTP. Even uncrewed space probes would be able to reach their destinations more quickly, opening the solar system to further exploration.

Recent developments in nuclear technology allow engineers to develop cheaper, lighter and safer nuclear thermal propulsion than was envisioned under the NERVA program. Once flight-ready articles are developed, deep-space missions would become even cheaper.

No one yet knows what the flight demonstration mission will entail. Often dummy payloads are used to test new space propulsion systems to avoid losing expensive space probes. SpaceX founder Elon Musk famously launched a Tesla roadster when testing the Falcon Heavy last year, which resulted in some of the most spectacular images ever to come out of the space age.

NASA might consider launching a flock of cubesats, low-cost probes the size of bread boxes. These could be developed by schools, universities and businesses. If the demonstration mission is successful, these tiny space probes would be sent deep into the solar system and would accomplish quite a bit of science and involve students in an actual space mission.

Farther afield, one can imagine how NTP technology would enhance both NASA’s and the private sector’s plans to explore and later settle and economically develop space. The Space Launch System, as tremendously expensive as it is, would be a better rocket with a nuclear upper stage. The SpaceX Starship and the Blue Origin New Glenn would also be more capable launch vehicles with NTP technology incorporated.

NASA would be advised to prepare for protests from the anti-nuclear movement when it launches its flight demonstration of a nuclear thermal rocket, similar to the ones that accompanied the launch of the Cassini probe to Saturn, powered by nuclear-fueled RTGs, in 1997. The space agency will conduct safety studies to ensure that the risk of a launch accident is as low as possible. Such studies likely will not deter protest demonstrators or even lawsuits, but they will answer any objections that anti-nuclear activists will offer.

Nuclear propulsion technology will mean the difference between a deep-space exploration program consisting of sorties that land on Mars and visit other destinations, do a lot of good science, then return, and one that expands human civilization throughout the solar system. More people and more cargo can be moved more cheaply, more quickly and more often using nuclear rockets than the tried-and-true chemical rocket engines that have been used ever since rocketry pioneer Robert Goddard conducted his first experiments almost a century ago.

Nuclear rockets, in short, will be as game-changing for space travel as the steam engine was for ocean voyages.

Mark Whittington is the author of space exploration studies “Why is It So Hard to Go Back to the Moon? as well as “The Moon, Mars and Beyond.”