Satellites and spacecraft are running on empty due to a worldwide shortage of traditional propulsion fuels. In response, two West Virginia University researchers are seeking alternative ways of powering the thrusters that keep satellites in orbit and could potentially drive deep space vessels.
Earl Scime, Oleg D. Jefimenko professor of physics and astronomy, and Thomas Steinberger, research assistant professor, both at the WVU Eberly College of Arts and Sciences, have been awarded a $748,000 grant from NASA’s Established Program to Stimulate Competitive Research to explore propulsion systems that do not rely on traditional fuel sources.
EPSCoR encourages states like West Virginia to seek federal funding to develop infrastructure that makes them competitive for future funding. Scime said he and Steinberger are seizing this opportunity to lay groundwork for conducting plasma thruster experiments. Plasma thrusters are used to keep satellites in orbit in their correct path, make orbital changes and correct a spacecraft’s attitude.
Years ago, spacecraft thrusters were powered by hydrazine, a toxic and flammable propellant source. Now, most are powered by a plasma thruster that uses xenon, an inert gas extracted from Earth’s atmosphere.
“It’s a costly process,” Scime said. “It’s usually done as a byproduct of steel manufacturing, and one of the largest distillation plants in the world for producing xenon is in Mariupol, Ukraine, which has been destroyed. A large fraction of the world’s xenon supply has dried up and it’s in very short supply.”
An alternative to xenon is krypton, though it, too, is hard to come by, as it was also produced in Ukraine. In addition, a large fraction was bought on the open market by SpaceX for its Starlink satellites. As krypton has become scarce, Starlink has switched to argon.
“Dependence on rare noble gases for spacecraft propulsion has become a real problem,” Scime said.
To that end, he and Steinberger have been studying iodine — which comes in solid form — as an alternative fuel.
“It has some huge advantages,” Steinberger said. “You can pack it into a small volume in a spacecraft. You don't need high pressure tanks or gas handling. A few years ago, we took an interest in iodine, got some apparatus to make iodine plasmas from the U.S. Air Force and we developed a diagnostic to measure the flow of iodine ions. Now we’re looking to the next step.”
Scime’s team has pioneered laser spectroscopy on iodine plasmas and developed the world’s first way to measure the speed of ionized iodine out of a thruster.
“We proposed to NASA to test iodine-based thrusters here using our laser techniques, so that people can have a better way of characterizing iodine thrusters,” he said.
Because iodine is messy and can cause respiratory problems in large test chambers, Scime and Steinberger are going to build a smaller, simpler chamber to develop and perfect ion thruster diagnostic technology that could then be ported to larger facilities.
While the team is in the early phases of the three-year project, they envision playing a role in developing ways to measure if a thruster is performing well.
“We’re building iodine-based thrusters,” Scime said. “So, in 20 years, we’d expect to see a lot of iodine propulsion systems on satellites, and maybe even on long duration missions to Mars. Hopefully we’ll see these kinds of thrusters in widespread use. And we would be part of the process of making them work well.”
No other group is conducting laser spectroscopy on ionized iodine, though many are pursuing research based on Scime and Steinberger’s work.
“We’ve demonstrated that it works,” Scime said. “The signals are really good. We expect a lot of other groups to be doing iodine laser spectroscopy soon.”
Scime and Steinberger said they hope WVU will become known as a place to do advanced diagnostics on both iodine-based and other kinds of thrusters.
“That’s where we see our niche being,” Scime said. “We’d be the go-to for people who say, ‘I want to run a thruster on this mix of gases. Can you give me a laser scheme that would allow me to measure the velocity of the particles coming out?’ And that’s what we’re going to do.
Melanie Page is the director of the NASA West Virginia Space Grant Consortium/NASA EPSCoR and associate vice president for creative and scholarly activity at the WVU Research Office.
“Recent data from 2021 shows that combined, the 28 EPSCoR states did not benefit as much from NASA funding and economic impact as did the one state of California,” Page said. “This is why the EPSCoR program is so vital — it begins to level the playing field with research infrastructure development so that the brilliant scientists from West Virginia can compete fairly for federal research funds.”
Scime anticipates having a lot of fun working on this project. “And, we’re well-positioned to do it,” he added. “NASA is pretty excited about us pushing this forward because they’re going to need the techniques.”
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