My research centers on optical observations of space debris using ground-based and space-based telescopes. How much debris is there, and what is it? Michigan telescopes ranging in size from the 0.6-m Curtis-Schmidt telescope on Cerro Tololo to the 6.5-m Magellan telescopes are being used for these studies. Objects the size of small iPhones can be detected at geosynchronous orbit (altitude = 36,000 km) using short exposures on the Magellan telescopes.
I served on the NASA delegation to the Inter-Agency Space Debris Coordination Committee (IADC) from 2001 to 2015.