Turning space junk into rocket fuel

Australian start-up Neumann Space has developed the Neumann Drive, a rocket designed to feed on space junk fuel itself. The rocket has been identified for its potential to remove fragmented rocket parts, defunct spacecraft and other drifting space junk and even power deep space exploration.

It is joining an Airbus mission to the International Space Station in 2019 to test its real-world capabilities and collect data. The rocket will be tethered to the ISS for the year-long trial before a free-flight model is tested.

Floating space junk is an increasingly serious issue that puts many satellites and space missions at risk. Neumann Space Founder and CTO Patrick Neumann said: “The system is useful for different things – one option is a tugboat or tow-truck device that can go around and focus on cleaning up junk, which means people who own defunct satellites have a lot less risk of hitting an active one.

“Another option is using the system’s short, sharp thrusts of power to keep stations and satellites doing their thing and staying in orbit.”

According to the European Space Agency there are about 18,000 large objects in orbit and more than 90% of them are space junk caused by more than 250 spacecraft explosions. There are also millions of smaller debris floating in space, which are too small for radars to track.

The drives “wire-triggered pulsed cathodic arc system” works like an arc welder and creates thrust by eroding material at the tip of a metal cathode. Once the material gets evaporated and ionised it is “spat down range” causing a pulsating thrust and propelling the rocket forward, like the way a bullet leaves the barrel of a gun.

Researchers have found that magnesium is the optimal fuel source but materials such as tungsten, chromium and carbon have also been successfully trialled.

Neumann said his research group was still working on developing a way to capture and reprocess space debris into a usable resource for the rocket when it is tested in space.

“A lot of the metals we are using already have aerospace applications and a lot of the structural parts of the (space) junk are made out of those metals,” he said. “As long as it’s a solid and conductive we can probably use it as fuel.”

A collision with a piece of material only a few millimetres in size is enough to alter a satellite’s orbit and offset its orientation.

Looking to the future, Neumann said the level of fuel efficiency of the Neumann Drive makes it powerful enough to send a probe from Earth’s lower orbit to the lower Mars orbit and back without needing to refuel.

He added that if “metal fuel stops” were placed at various points in space, it could further increase the reach of the rocket, leading to deeper space exploration.