While the old US Space Fence radar tracking system (officially called the Air Force Space Surveillance System) which had tracked crossing orbiting objects since 1961, was retired for cost reasons in 2013, plans for its replacement are now well underway. A contract worth US$915 million has been awarded by the US Department of Defense to Lockheed Martin for the construction of the new Space Fence system which will include an S-band radar station in Kwajelein Atoll in the Pacific (to be completed by 2018) and an option for one in Western Australia. The system will allow all objects greater than 5cm diameter (about 200,000) to be tracked in low Earth orbits out to 1,900km altitude. This will allow the observation of large space debris as well as cubesat spacecraft. The data will be fed to the US Joint Space Operations Center. A fuller description is on Spaceflightnow.com
