Ground-based radar first caught glimpse of an abnormally high concentration of objects drifting through space. The objects were later identified as droplets of reactor coolant that eked from leaking Russian space reactors. Shown here are Haystack and HAX radars located in Tyngsboro, Massachusetts. These radars collect hundreds of hours of orbital debris data each per year. They are NASA's primary source of data on centimeter-size debris. Credit: NASA/JSC Orbital Debris Office
