Space Fence

From 1961 to 2013, the U.S. Air Force operated a ground-based radar network that detected objects in space passing over the United States. It's name was Air Force Space Surveillance System or simply Space Fence. It used VHF radio, running at 216.9 MHz. This relatively low frequency limited the size of objects that could be reliably detected.

A new space fence, based on S-band radar (2 to 4 GHz), and capable of detecting much smaller objects than the original space fence, is now being built in the Marshall Islands. Named the Kwajalein Space Fence, it is being built by Lockheed Martin. The system will require additional locations in the future. A likely location is Diego Garcia in the Indian Ocean, which already has a Ground Based Electro-Optical Deep Space Surveillance station.

AFSSS space fence receiver
San Diego, California, US
Active: 1961-2013
AFSSS space fence receiver
Elephant Butte, New Mexico, US
Active: 1961-2013
AFSSS space fence receiver
Red River, Arkansas, US
Active: 1961-2013
AFSSS space fence receiver
Silver Lake, Mississippi, US
Active: 1961-2013
AFSSS space fence receiver
Hawkinsville, Georgia, US
Active: 1961-2013
AFSSS space fence receiver
Tattnall, Georgia, US
Active: 1961-2013
AFSSS space fence transmitter
Lake Kickapoo, Texas, US
Active: 1961-2013
AFSSS space fence transmitter
Gila River, Arizona, US
Active: 1961-2013
AFSSS space fence transmitter
Jordan Lake, Alabama, US
Active: 1961-2013
Kwajalein Space Fence
, Marshall Islands
Active: 2020-Present
Link: Lockheed Martin
Kwajalein Space Fence