New Ion Thruster Can Be Powered by Astronaut WasteIn space, fuel is hard to come by. The chemical rockets we power most of our satellites and space stations with requires fuel that is expensive and must be shuttled up from the surface. Even ion engines suffer this problem largely relying on noble gasses like Xenon.
But that could be about to change. A new ion engine being designed in Australia could be powered by, and I'm not making this up, piss.
The new engine is a type of thruster known as a Helicon Double Layer Thruster, or HDLT. A HDLT is a true ion thruster in that it expels equal parts both positive and negative ions. It also happens to be simpler than most ion thrusters, while also accepting far more fuel sources. Basically, the entire contraption centers around a tube into with gas is injected. That gas is bombarded by a specific radio frequency--13.56 MHz, to be precise--which forms a double layer electric field. This field acts as a nozzle for ions, which get shot out the back.
As explains Australia's National University (ANU):
This double layer can be thought of as a thin standing shock wave across which there exists a strong electric field gradient. It is this electric field that accelerates ions from the source plasma to very high exhaust velocities creating thrust. Because the double layer is purely the result of plasma density, system and magnetic field geometry, no accelerating grids are required. Also, because there is equal flux of electrons and positive ions from the thruster there is no need for a neutraliser. It is in this sense that the HDLT is a "true" plasma thruster as it ejects equal numbers of both positive ions and negative electrons.
These things are incredibly flexible, able to run on almost anything. As explained chief researcher Rod Boswell:
"we can use any type of propellant, including piss. In the International Space Station, there's a system that extracts water from urine, known as the ‘Russian piss-presser'. The result ends up with a pH around one--we could easily use that. Xenon is expensive--why not use what's already there?"So our future rockets might just be powered by our own waste.