NASA describes nuclear spacecraft as a ‘game-changer’ for Mars trip

21 Aug 2019

The sixth meeting of the US National Space Council with vice-president Mike Pence at the podium. Image: NASA/Aubrey Gemignani

The head of NASA has welcomed a future where nuclear thermal propulsion takes spacecraft to Mars and beyond.

Chemical propulsion used since the dawn of the space age has largely gone unchanged, but engineers are looking for new ways to power spacecraft to the furthest reaches of space. As reported by, NASA’s administrator, Jim Bridenstine, revealed at the sixth meeting of the US National Space Council that the agency is looking at the use of nuclear thermal propulsion.

This would harness the immense heat emitted by fission reactions to accelerate propellants such as hydrogen to take spacecraft up to previously unachievable speeds.

“[Nuclear technology] is absolutely a game-changer for what NASA is trying to achieve” Bridenstine said. “That gives us an opportunity to really protect life, when we talk about the radiation dose when we travel between Earth and Mars.”

Estimates suggest that such engines could potentially see a spacecraft reach the Red Planet in as little as three months, making it twice as fast as traditional chemical propulsion.

Bringing war to space

Additionally, Bridenstine said that nuclear thermal propulsion could be useful for applications closer to Earth. This could include allowing spacecraft in Earth’s orbit the capability of quickly avoiding anti-satellite weapons launched from the surface.

According to the acting US director of national intelligence, Joseph Maguire, Russia and China are already developing such weapons systems.

“Both countries view the capability to attack space systems and services as part of their broader efforts to deter or defeat an adversary in combat,” Maguire said. “In short, the threat to US and allied space systems continues to grow unabated.”

Looking away from spacecraft, another panellist at the event said that small fission reactors could be used to power energy weapons on off-world military bases, such as on the moon and further afield.

Rex Geveden, president and CEO of BWX Technologies, said: “You certainly can imagine using a compact, high-temperature gas reactor to power a directed energy weapon, for example,” he said. “[The US is] using diesel fuel now, but that’s not sustainable over a sustained battle.”

Colm Gorey was a senior journalist with Silicon Republic