The Navy's involvement in space surveillance dates back to 1958, when a multi-static radar fence called "NAVSPASUR" was established along the 33rd parallel from coast to coast. It reaches straight up 10,000 miles into space with fan-shaped beams which are fixed in position, not scanned. It consists of six receivers and three transmitters, the most powerful of which is located near Lake Kickapoo, Texas. A data processing center is located in Dahlgren, Va. Its observations are fed to NORAD, and comprise about 21% of all input to the NORAD Space Control Center. Typical satellite orbits will cross the fence about 4-5 times per day.