U.S. Air Force Fact Sheet

There are approximately 10,000 known objects in orbit around the Earth. These objects range from active payloads, such as satellites, to "space junk" such as launch vehicle debris and debris generated from satellite breakups.
U.S. Strategic Command's Space Control Center, located within Cheyenne Mountain Air Force Station in Colorado Springs, Colo., is responsible for tracking all man-made objects in orbit. The center receives orbital data from Ground-Based Electro-Optical Deep Space Surveillance (GEODSS) sites assigned to Air Force Space Command (AFSPC). GEODSS sites play a vital role in tracking these deep space objects. Over 2,500 objects, including geostationary communications satellites, are in deep space orbits more than 3,000 miles from Earth.
There are three operational GEODSS sites that report to the 18th Space Surviellance Squadron, Edwards AFB Calif. - Socorro, N.M.; Maui, Hawaii; and Diego Garcia, British Indian Ocean Territories.

GEODSS performs its mission using a telescope, low-light-level television cameras, and computers - three proven technologies. Each site has three telescopes, with the exception of Socorro with two main and one auxiliary. The main telescopes have a 40-inch aperture and a two-degree field of view. The auxiliary telescope at Det 1, has a 15" aperture and six-degree field of view. The upgrade underway to replace the auxiliary telescope with main telescope and complete refurbishment of all the GEODSS telescopes will culminate with Det 1 in 2002. The telescopes are able to "see" objects 10,000 times dimmer than the human eye can detect. This sensitivity allows the system to only operate at night. As with any optical system, cloud cover and local weather conditions directly influence its effectiveness.
The GEODSS telescopes scan the sky at the same rate as the stars appear to move. This keeps the distant stars in the same positions in the field of view. As the telescopes slowly move, the GEODSS cameras take very rapid electronic snapshots of the field of view. Four computers then take these snapshots and overlay them on each other. Star images - which remain fixed - are electronically erased. Man-made space objects, however, do not remain fixed, and their movements show up as tiny streaks viewed on a console screen. Computers measure these streaks and use the data to figure the positions of objects such as satellites in orbits from 3,000 to 22,000 miles. This information is used to update the list of orbiting objects and sent nearly instantaneously from the sites to Cheyenne Mountain Air Station, Colo.

The GEODSS system is the successor to the Baker-Nunn camera, a less accurate and older system developed in the mid-1950’s to provide surveillance data. In January 1999, site hardware and software was modified and a new Optical Command, Control, and Communication Facility (OC3F) was placed at Edwards AFB, Calif., which became operational in February 2000. The OC3F optimizes tasking of all GEODSS telescopes through its dynamic scheduling program, increasing GEODSS accuracy by 75%. GEODSS system can track objects as small as a basketball more than 20,000 miles in space, and is a vital part of AFSPC’s space sureviellance network (SSN).

Point of Contact
Air Force Space Command, Public Affairs Office; 150 Vandenberg St., Suite 1105; Peterson AFB, CO 80914-4500; DSN 692-3731, or (719) 554-3731.

April 2003

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