US Air Force Wants To See Some Atomic Motors For Future Spacecraft

Lockheed Martin has been awarded $33.7 million by the US Air Force Research Laboratory to develop nuclear-powered electric propulsion systems for spacecraft.

Under the military lab's Joint Emergent Technology Supplying On-Orbit Nuclear (JETSON) High Power program, Lockheed Martin will work with Space Nuclear Power Corp and BWX Technologies to build a fission reactor that can be used to fly probes through space rather than lift them up into orbit from Earth.

That reactor system is expected to split the atoms in uranium fuel, and use the resulting heat to drive Stirling engines connected to generators to produce between between six and 20 kW of electric capacity. That electricity can then be used to power the craft's onboard electronics and electric Hall thrusters for propulsion. Hall engines work by using a magnetic field to accelerate ions to produce thrust.

This is on top of any power that can be generated from any attached solar panels; when there's not enough light, this atomic system ought to be highly useful.

"Nuclear fission development for space applications is key to introducing technologies that could dramatically change how we move and explore in the vastness of space," said Barry Miles, JETSON program manager and principal investigator, at Lockheed Martin, in a canned statement.

"From high-power electrical subsystem and electric propulsion, to nuclear thermal propulsion or fission surface power, Lockheed Martin is focused on developing these systems with our important government agencies and industry partners."

As to why the Air Force is so interested in fission-driven craft, Andy Phelps, CEO of Space Nuclear Power Corp, shed some light on that: military missions and exploration.

“A future JETSON flight experiment will enhance maneuver and power capabilities shaping future space force operations,” Phelps said. “We’re giving our country a technical leap – both terrestrially and on-orbit – as well as the ability to expand future space exploration.”

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Interestingly enough, Lockheed Martin stressed in its announcement of the funding that we won't have anything to worry about regarding strapping a nuclear reactor to a rocket to lift it up into space:

The rocket blows up, which they sometimes do, we assume that uranium will be distributed so far and wide, it won't be a problem, or crash back as a lump in a way that doesn't ruin someone's year.

For exploratory work, not only can such fission reactors propel probes to boldly venture forth, they can also keep them warm enough to operate in the frigid temperatures of deep space. The most distant human-made objects, Voyager 1 and 2, for example, are kept warm by their radioisotope thermoelectric generators (RTGs), where heat is produced from the natural decay of plutonium-238 atoms.

The proposed uranium fission reactor system will ideally provide more energy than RTGs and solar arrays. Atomic motors in space have been on the minds of scientists and engineers for decades; the concept was tested in 1965 when the US launched SNAP-10A, an experimental nuclear-powered satellite powered by rods of uranium-zirconium-hydride fuel.

Unfortunately, the probe broke down 43 days into its planned year-long mission due after a voltage regulator failed and the reactor had to be shut down.

Lockheed Martin also acknowledged that JETSON "draws heavily from the design and lessons of the 2018 Kilopower Reactor Using Stirling Technology (KRUSTY) demonstration led by NASA and the DoE’s National Nuclear Security Administration."

NASA continues to work on nuclear thermal propulsion hardware, and believes the technology is key to helping astronauts reach Mars and explore space beyond the Red Planet more efficiently. Specifically, the space agency and DARPA are toiling away on a Demonstration Rocket for Agile Cislunar Operations (DRACO) that aims to drive a nuclear-powered craft in space as soon as 2027. ®