Satellites are almost always illuminated by the sun, apart from short transitions to Earth’s shadow. The light that a satellite reflects can help reveal the solution to a structural malfunction.

Carolin Frueh is among only a handful of researchers who have persisted in using a complex technique that can diagnose a problem from thousands of miles away based on how the satellite reflects sunlight.

«While you’re driving a car, you can’t get out of the car to check if something has fallen off or gotten damaged. But you know that there might be a problem,» said Frueh (pronounced «free»), an assistant professor in Purdue University’s School of Aeronautics and Astronautics.

«An operator might notice that a satellite is unstable or not charging properly. An outside perspective can tell if it’s because something broke off, or if a panel or antenna is not properly oriented, for example.»

Not diagnosing the problem increases chances of losing or not being able to reestablish communication with the satellite. When communication is lost, a satellite could become pieces of debris that stay in space for hundreds of years or indefinitely unless actively removed.

This «space junk» poses a danger to other spacecraft. There are about 100,000 pieces of debris larger than a penny orbiting Earth, according to a U.S. Strategic Command database.

Story Source:
Materials provided by Purdue University. Original written by Kayla Wiles. Note: Content may be edited for style and length.