By the time he was in high school, dean and professor Alec Gallimore had two clear goals: become an astronaut and fly a spacecraft he’d helped design. He knows there were times when this particular career plan sounded, well, kind of out there.
But getting out there was really the whole point.
Gallimore’s interest in electric propulsion grew out of his love for science fiction – specifically Star Trek and 2001: A Space Odyssey – and his fascination with the idea of taking high-speed travel to the extreme. But unlike a lot of teenage sci-fi fans, Gallimore, now the Robert J. Vlasic Dean of Engineering, the Richard F. and Eleanor A. Towner Professor of Engineering, and an Arthur F. Thurnau Professor, put himself on course for his own space odyssey.
His Plasmadynamics and Electric Propulsion Lab works on leveraging the long-haul potential of electric propulsion to build systems capable of extremely long space missions. The X3 plasma thruster his team developed in partnership with NASA and the U.S. Air Force is part of a prototype propulsion system that NASA is considering for a future mission sending humans to Mars.
There are two dominant ways to move a spacecraft, depending on how far it’s going and – to a degree – how quickly it needs to get there. Most people are familiar with chemical propulsion – burning a chemical fuel that generates enough thrust to send big, heavy payloads into space. Chemical systems give a big push, then shut down once the craft reaches its desired speed or orbit. They’re great for “short” trips, like going to the moon.
Electric propulsion, on the other hand, uses onboard spacecraft power, typically produced from solar cells, to superheat a gas – usually xenon or krypton. The heat causes electrons to break away from the gas molecules, forming a plasma of positively charged ions and negatively charged electrons. Then the system applies magnetism and voltage, pushing the ions out the back end of the craft at speeds 10 times faster than combustion can achieve.
Electric propulsion uses far less propellant than combustion and, given enough time, can reach speeds about 10 times that of a chemical system.
NASA’s Apollo missions, for example, used chemical combustion to reach the moon in three days. A plasma system could cover that same 238,900 miles in 2 hours but would take months to reach that speed. That makes electric propulsion especially well-suited to providing a sustained push for really long trips – like going to Mars.
Initially looking for his own ticket to space, Gallimore earned a bachelor’s in aeronautical engineering at Rensselaer Polytechnic Institute and his Master’s and Ph.D. in aerospace engineering at Princeton. He worked at NASA while still a student and learned a lot about what it takes to be an astronaut. He met astronaut Franklin Chang Diaz, who had flown on seven space shuttle missions, and decided to emulate the mechanical engineer and physicist, who’d also developed his own plasma propulsion system.
At the time, NASA required prospective astronauts to have some work experience, so in 1992, when Michigan offered Gallimore an opportunity to inherit the largest vacuum chamber at any university, he took U-M up on the offer. Besides, he figured a short-term stint as a professor would be fun in that he would work with very bright students and it would spare him the hassle of working for a traditional boss.
He never expected to love it so much. As Gallimore ticks off the list of things he considers the best parts of his job – his research; his lab; being around smart, enthusiastic young people; mentoring graduate students – it’s clear he has no regrets.
“I love learning things and making an impact,” he said.
Gallimore has mentored more than 35 PhD students, and he considers each of them extended family. He’s celebrated with them, laughed with them, counseled and comforted them. They send him photos of new babies and pictures from visits with other former students.
Not long ago, Gallimore received an email with an attached picture of a man in his 40s holding an award.
“Dear Professor Gallimore,” the letter read. “I was in your undergraduate Spacecraft Design and Propulsion classes a little over 18 years ago, and I wanted to let you know how your lecture on electric propulsion shaped me…”
The former student had become an engineer on a Boeing communications satellite project. The award he received for his work on the project sparked conversations about mentoring and great teachers.
“…I felt it was long overdue that I share this with you,” he wrote.
Meanwhile, Gallimore’s research continues to shape the electric propulsion field. His lab conducted research on the thruster used on the still-ongoing NASA Dawn mission, a spacecraft that has orbited two dwarf planets in the asteroid belt between Mars and Jupiter. Under his guidance Michigan has led a six-university Air Force Center of Excellence since 2010.
And even after 30 years of work with plasma thrusters, Gallimore retains a sense of wonder that these things actually work.
“I’m always awed by it,” he said. “You’re taking a wire, and you’re taking an inert gas, and somehow you’re combining those things to make thrust. It’s kind of magical.”