First nuclear fusion pulsed plasma space engine tested

In 1964, the Soviet Union launched its Zond 2 deep space probe for an anticipated approach to Mars. The mission proved a failure when all communications were lost about six months later, but it is still remembered for the experimental ion thrusters it carried for attitude control. These were one-of-a-kind pulsating plasma PPT thrusters, which also worked well

Now FireStart wants to bring the same engines back into use, but with an interesting extra: an aneutronic nuclear fusion that will give a further and notable boost to the plasma engine.

Engines from the known principle, with something extra

These pulsed plasma thrusters never caught on, but their simplicity and robust design attracted the attention of engineers from time to time, and they were pioneered by NASA on its Earth Observing 1 mission in 2000. The normal problem with these engines is that the flow of gas is at a very high speed, but the quantity of accelerated gases is very low

Pulsed plasma engine diagram

All of this would be a footnote in the history of space exploration if it weren’t for a new twist added to the design by the United States Air Force Research Laboratory (AFRL) and its commercial partners at Rocketstar. Their scientists and engineers have introduced so-called aneutronic nuclear fusion, that is, a type of nuclear fusion that does not release neutrons.

Aneutronic nuclear fusion is that, for example, which occurs when a proton hits a boron 11 nucleus which, with the addition of the proton, becomes carbon 12, with the release of 8.7 MeV of energy. However, this carbon is highly excited and therefore splits into three helium 4 atoms.

What RocketStar is doing with its version of aneutronic nuclear fusion is using water as a propellant for its M1.5 FireStar Drive, which is a pulsed plasma thruster enhanced by nuclear fusion. At a certain point, boron is added to this water.

When the mixture of water and boron is struck excited and transformed into plasma, the water molecules break down into oxygen and hydrogen, i.e. protons. and these and are released at high speed. These protons collide with boron atoms, fusing with them to create a very unstable carbon molecule, called carbon-12. This breaks down almost immediately into alpha radiation, i.e. helium nuclei.

The result is a sort of afterburner effect in which the energy released increases thrust by half, and by mixing the boron with water, the need for a metallic boron shield is eliminated. The FireStar Drive is expected to fly on missions on the D-Orbit-owned OTV ION satellite carrier in July and October this year.

“We are thrilled with the results of our initial testing of an idea our team has been exploring for some time,” said Chris Craddock, CEO of RocketStar. “On a napkin at a conference in Florida, I sketched out this idea and described it to Wes Faler, the founder of Miles Space. He was very skilled in developing both the basic thruster and the fusion upgrade. We acquired Miles Space and Faler is now our CTO. Now I’m excited to take our already stellar powertrain and make it fusion-enhanced, with dramatic performance improvements.