When operational, the Space Fence will include several ground-based S-band radars that continuously track objects in near and mid-Earth orbit. The sensitivity and short wavelength of S-band radar lets the Fence track objects the size of a softball 1,200 miles above Earth. The Fence should improve the safety of orbiting satellites and more quickly detect such “space events” as the collision between a U.S. Iridium communications satellite and Russian Cosmos communications satellite in 2009. That collision alone ejected several hundred pieces of debris into orbit and each could become a menace to other spacecraft.
When completed, the Space Fence will replace the Air Force Space Surveillance System, or VHS Fence, that’s been in service since 1961.