Rocket scientist Alec Gallimore is playing a critical role in the development of technology needed to take humans deeper into space.
When University of Michigan aerospace engineer Alec Gallimore was growing up, all he wanted to do was become an astronaut. That desire never left him, even through graduate school, he says in a 2010 video profile posted on YouTube. His plan after graduating in 1992 with his PhD from Princeton University—he is listed among the members of the Association of Black Princeton Alumni—was to spend three to five years in academia, then join the astronaut corps. But “I just fell love with the job,” says Gallimore, who has been teaching in Michigan’s department of aerospace engineering ever since.
He may not get to be the first human to step foot on Mars, but Gallimore is playing a key role in making that dream a reality for some future astronaut. Gallimore’s Plasmadynamics and Electric Propulsion Laboratory (PEPL) has designed the thrusters at the core of an advanced propulsion system being developed by Washington-based Aerojet Rocketdyne, which was selected in March for participation in NASA’s Next Space Technologies for Exploration Partnerships (NextSTEP). That participation comes with funding: Roughly $1 million over the next three years will go to the PEPL alone.
According to the NextSTEP website, the program aims to “[develop the] capabilities to support more extensive [manned] missions to deep-space destinations such as the space around the moon, known as cis-lunar space, and Mars.” To get to deep space, however, NASA says it needs electric propulsion technology that can generate at least 300 kilowatts (kW) of power—60 times the power generated by currently deployed technologies.
Propulsion systems are what keep the spacecraft going once it reaches orbit and needs another boost to go deeper into space. And generally, those systems are based on heating a gas (like xenon) to extreme temperatures, turning it into plasma, and accelerating the ions within the plasma by subjecting them to an electric field. Those accelerating ions—which exit the spacecraft through the thruster’s discharge channel—generate a discharge power that is sufficient to propel spacecraft. Compared to chemical systems that run on dense liquid fuel, these electric propulsion systems weigh much less and are more efficient.
And that’s where Gallimore’s PEPL comes in. In partnership with the Air Force Research Laboratory and NASA, the PEPL has designed the X3 Nested-Channel Hall Thruster, which can theoretically generate more than 200 kW of discharge power. Nesting three discharge channels (the image below is of the X2, with two nested channels) makes this design lighter and smaller than three separate thrusters of equivalent power. (Gallimore’s PhD student, Roland Florenz, describes the technology in full detail in his dissertation.)
Aerojet Rocketdyne will use the NextSTEP award to complete the development of a system to convert the electrical power collected by a spacecraft’s solar panels into the power needed to ionize the xenon gas that feeds into the PEPL thruster. Also, more lab testing is needed to observe the X3 Hall Thruster at those unprecedented discharge power levels and to see how long the boost would last.
Besides his work as a rocket scientist, Gallimore serves as associate dean for academic affairs for the university’s college of engineering. His responsibilities include oversight of the budget and of hiring and promotion process for faculty. Apparently, his skills also extend to the classroom: In 2006, he was named an Arthur F. Thurnau Professor in recognition of his excellence in teaching.