Micci, Michael M. Ph.D.
Professor of Aerospace Engineering and Director of Graduate Studies
Mike Micci is nothing if not persistent. Now a professor of aerospace engineering at Penn State, he has been working on rocket propulsion since he was a graduate student at Princeton in the late 1970s – specifically on microwave plasma spacecraft thrusters. Today, his work is approaching the point where a test in space should be possible…within the next couple of years. Meanwhile, in a machine shop in Centre Hall, Penn., about 12 miles from the Penn State University Park campus, a flight-weight prototype of such a thruster is being built under Micci’s direction.
Micci was a new assistant professor of aerospace engineering at Penn State in 1981 when he read a paper by a NASA-funded group that was experimenting with microwave-induced plasma as a potential means of propelling a space vehicle. Their results were “so-so,” said Micci. With his background in fluid mechanics, jets, and rockets, he thought he had a better approach, one that involved using higher gas pressure and positioning the plasma itself closer to the entrance of the rocket nozzle. Soon thereafter, he and a mechanical engineering colleague received funding from the U.S. Air Force to pursue the idea.
The mechanical engineering professor was a theoretician, interested in computational modeling. For his own part, Micci likes to design and run experiments. On his way to earning his doctorate, he performed more than 40 of them. Micci explains the appeal: “An experiment is reality. What you get is real. What the computer gives you, you hope is real.”
Micci’s work on plasma thrusters, today funded by Northrop Grumman Corp., has the potential to lower the launch and operating costs of deep space probes and communications satellites by making them more fuel efficient and durable. Fundamentally, this is because electric propulsion is more efficient than chemical propulsion – yielding a higher specific impulse, which means more thrust per the weight of fuel burned in one second. So, while an electric propulsion device has to operate longer than a chemically powered one to change either a vehicle’s trajectory or its speed, in the end it uses less propellant to effect that change, making it more efficient over the long haul. In fact, an electric propulsion device firing constantly will eventually enable a space probe on a long mission to achieve a higher velocity than will chemical propulsion.
Today’s communications and weather satellites, essential for many purposes here on Earth, rely on electric thrusters to make the course adjustments that keep them in geosynchronous orbit. Deep Space 1, launched by NASA in 1997 to – among other things -- visit comets, is among the missions that rely on electric propulsion devices, in this case an electrostatic ion thruster powered by solar energy.
Micci and his colleagues are developing a smaller and more powerful propulsion device, one that uses high-frequency microwaves to ionize the propellant atoms, in other words to create the plasma that yields thrust. The use of high frequency microwaves not only makes for a compact device, it supports overall durability by eliminating the need for a cathode, which is subject to erosion over time. In experiments carried out in a vacuum chamber to simulate space, Micci’s team has produced up to 350 watts of electrical power using microwaves at a frequency of 8 gigahertz.
Mike Micci has received three patents for microwave plasma devices, and his microwave thruster was a finalist in 1997 for the Discover Magazine Award for Technological Innovation in the Aviation/Aerospace category. Micci works on other forms of propulsion as well, including chemical propellant rockets and microwave plasma air-breathing thrusters. His extensive publication credits include co-editing “Micropropulsion for Small Spacecraft,” published in 2000 by the American Institute of Aeronautics and Astronautics
Micci grew up in Joliet, Ill., earning his undergraduate degree in aeronautical and astronautical engineering at the University of Illinois at Urbana-Champaign. His interest in all things electrical was piqued early by his father, an electrician who kept a well-equipped workshop and encouraged his son to pursue a technical profession. As a first grader in 1962, Micci was fascinated by TV coverage of John Glenn orbiting the Earth in Friendship 7. In junior high, he became interested in model rocketry – a hobby he pursues today with his two young children. Their aspirations having outgrown the park nearest their house, they are looking for a larger launch site.