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How an Australian College Student Did What NASA Couldn't

Paddy Neumann's final project—which proposes using junk metal as rocket fuel—could change space travel forever.

Paddy Neumann kind of looks like someone who's really into brewing beer. But back when he was a third year student at the University of Sydney, the now Dr. Neumann started on a course of experimentation that would see him beat innovations by NASA's top scientists.

For his final research project, Neumann was working with the university's plasma discharge, mapping the electric and magnetic charges around it. He noticed the particles moving through the machine were going really fast. In fact, they were clocking in at around 14 miles per second.


"I looked at my numbers from that final year project and thought, You could probably make a rocket out of this," he says. Particularly when you consider that conventional hydrogen-oxygen rockets only get around 2.8 miles per second.

Through his honors, masters, and PhD, Neumann refined his idea, eventually arriving at the Neumann Drive, which is a world record–breaking ion engine. Right now, the drive can achieve more than 11,000 seconds of specific impulse—which is one measure of how efficient a rocket engine is. The higher the number, the better. Paddy says that by comparison, NASA's best experimental efforts max out at 9,600 seconds of specific impulse.

To move through space, vessels need a push, which comes from the propellant that spurts out the back of a rocket. With a high specific impulse, the Neumann Drive can push through space using less fuel, allowing rocket ships to be lighter and hold more room for cargo.

"This was just one of the cool things that happen when you putter around in a lab for long enough," Neumann says. "It's me having a go with something that lots of people have used in the industry for a long time but putting it under conditions that nobody has really tested… no one was crazy enough to put this much current through it."

So how does the Neumann Drive work exactly? Well, that's where things get a little technical. "It works using physics kind of similar to how an arc welder works," Neumann explains. "You strike an arc between the cathode and the anode, and that erodes cathode material… ionizes it, and accelerates it away from the cathode. It moves really, really fast."


In the simplest terms, the idea is that electricity will be used to heat up solid metal, turning it into plasma, which is then shot out the back of the rocket. Neumann Space's tests show magnesium is the most efficient fuel.

Another unique aspect of Neumann's ion engine is that—unlike other rockets that need to carry their entire fuel load from Earth—the Neumann Drive can be powered by a fuel that's plentiful in space: space junk.

"Much as how whenever humanity has gone to explore some place new, such as Mt. Everest, where we leave oxygen bottles behind, whenever we've gone to space, we've left rubbish behind," Neumann says. "Somebody should clean it up."

Old satellites that are on the way out would make great fuel. As could spent stages from rockets, which are what propel ships up through the Earth's atmosphere—before being ejected away into space. Both are rich in "aerospace metals" and could be captured, melted down, and repurposed into solid fuel for the Neumann Drive.

Obviously there's a lot of technology that needs to be developed for this to work—melting metal into fuel in outer space isn't something we're great at just yet. But Neumann already envisions an entire space economy. He speculates people will become "junk hunters," heading out into space in search for fuel that they can sell on. Neumann Drives will be everywhere, keeping satellites in orbit, even directing asteroids close to Earth to be mined for precious metals.

And then there's the drive's capacity to power long-distance space travel. While it doesn't generate enough thrust to get a rocket ship off the ground, once you're in space, those high-specific impulse numbers mean the Neumann Drive can move a vessel very efficiently.

Right now, the Neumann Drive is very much still a laboratory prototype. To get to the next stage, Neumann and his team need money—something that can be hard to come by in Australia. Investors aren't exactly used to betting on inventions that are as complex or forward-focused as the Neumann Drive.

Australia is spending about $770 million a year on space but very little goes to private enterprise. Most is spent on paying other countries to send satellites into orbit for us and "classified military" projects.

So to fund the next stage of development, Neumann and his team are getting creative. They're going to sell off excess room on a platform they've been given on International Space Station, which is scheduled to set off in 2018. If all goes to plan, the Neumann Drive will spend a year in space, getting tested out, in real conditions.

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