NASA and the DoD cooperate and share responsibilities for characterizing the satellite (including orbital debris) environment. DoD’s Space Surveillance Network tracks discrete objects as small as 2 inches (5 centimeters) in diameter in low Earth orbit and about 1 yard (1 meter) in geosynchronous orbit. Currently, about 15,000 officially cataloged objects are still in orbit. The total number of tracked objects exceeds 21,000. Using special ground-based sensors and inspections of returned satellite surfaces, NASA statistically determines the extent of the population for objects less than 4 inches (10 centimeters) in diameter.
http://www.nasa.gov/mission_pages/station/news/orbital_debris.html
I'm still assuming that something the size of a football field is larger than 1 yard.
You got me on that one. I didn’t want to go into a long winded discussion about detecting objects in space. It can be done, it is done, but it isn’t as easy as the paragraph makes it seem.