Undergraduate students at the University of Michigan in Ann Arbor are testing the theory of using electromagnetism rather than thrusters to keep small satellites in orbit around the Earth. The team’s experiment was scheduled to launch Jan. 10 but was delayed.
The test satellite, called MiTEE-1 (which stands for Miniature Tether Electrodynamics Experiment) was scheduled to fly from the Mojave Air and Space Port in California as part of Virgin Orbit’s Launch Demo 2. That flight launched from under the wing of a 747 Jan. 18.
Maneuvering for satellites of any size typically comes from thrusters that require fuel, which adds weight to the vehicle. The U-M students are studying the theory of tethering two small satellites with a wire 10 to 30 meters long that is able to drive current in either direction using power from solar panels and closing the electrical circuit through the Earth’s ionosphere.
When a wire conducts a current in a magnetic field, that magnetic field exerts a force on the wire. The team plans to use the force from the Earth’s magnetic field to climb higher in orbit, compensating for the drag of the atmosphere.
While Earth’s atmosphere is much thicker on the ground, a scattering of air particles stretch all the way up to low Earth orbit — the territory of about 60 percent of Earth-orbiting satellites. Small satellites are more strongly affected by the drag of the upper atmosphere than large satellites, slowing their orbits, and causing them to drop toward the Earth.
“These smaller spacecraft just don’t last very long, maybe even days to weeks, or a few months, dependent upon how high they are,” says Brian Gilchrist, a professor of electrical engineering and computer science, who supervised the team.
MiTEE-1 was designed and built by more than 250 students over a course of six years. They were mentored by engineers and technicians of the U-M Space Physics Research Laboratory. The version launching will have a deployable rigid boom, one meter long, between one satellite the size of a bread box and another the size of a large smartphone. It will measure how much current can be drawn from the ionosphere under different conditions.
The experiment will be launched on a CubeSat, about the size of a loaf of bread, designed to hitch a ride into space with a major mission, such as Virgin Orbit’s Launch Demo 2. CubeSats are low-cost ways to test out new technologies or enable students to get hands-on experience with space exploration.
“It’s the first time MiTEE will launch a satellite, and it’s been a long time coming,” says Lauren Citkowski, an aerospace engineering senior. “I’m excited to finally see the result of years of effort.”
The MiTEE project will continue at U-M, taking data from this satellite to plan the next. A future version with a longer tether between the satellites, 30 feet or more, would demonstrate that this form of electromagnetic propulsion could keep the device in orbit.
The MiTEE project participates in the Multidisciplinary Design Program, which helps match students from across the university with faculty research — from first-year undergraduates to masters level students. Through MDP, the U-M College of Engineering also funds fellowships for students from low- and middle-income families, or who are in the first generation of the family to attend college. All students who participate in MDP gain hands-on experience in research and industry, preparing them for careers in engineering and space sciences.