An increasing number of services and applications are relying on space-based technology. Examples include navigation, satellite broadcasting, and even medical research. Yet such services could be easily interrupted by collisions with space debris. To gain time to react to occurrences that might impact the nation's space assets and missions, the US Air Force has awarded contracts to both Lockheed Martin and Raytheon for the next phase of Space Fence. The program will increase space situational awareness and enhance safety for both manned and unmanned space operations.

By fielding two or three high-power, S-band, ground-based radars, Space Fence will enable the Air Force to detect, track, measure, and catalog resident space objectsprimarily in low-earth orbit. Space Fence will replace the existing Air Force Space Surveillance System, or VHF Fence, which has been in service since the early 1960s. Compared to current systems, the higher frequency of the new Space Fence radars will allow for the detection of much smaller microsatellites and debris (see photo). Although the current VHF system is located in the continental US, the Space Fence radars will be located at strategic sites around the world to expand global surveillance coverage into the Southern hemisphere.

Lockheed Martin received a $107-million follow-on contract for the next phase of Space Fence. Under the 18-month contract, Lockheed Martin will further develop and prototype its ground-based radar system design in preparation for a final Space Fence production contract next year. In June 2009, Lockheed Martin was one of three industry teams awarded a $30-million contract to begin concept development for Space Fence. During the recent system-design-review phase, the team reduced risks for its solution by prototyping, designing, and performing trade studies and analysis of potential system configurations. The team also conducted site and facility studies and developed net-centric approaches to integrate the new Space Fence with the existing architecture of the Space Surveillance Network.

Raytheon Co. also has been contracted to further the design of the Space Fence system and will deliver a preliminary design. In addition, the firm will test a functional radar prototype to ensure cost, schedule certainty, and technical maturity of the final design in support of Milestone Bthe point at which a recommendation is made and approval is sought regarding the start or continuation of an acquisition program. Specifically, Milestone B approves entry into the engineering and manufacturing development phase.

The work performed during this phase continues to reduce total program risk through the development of a preliminary design with mature technologies that meet or exceed Technology Readiness Level 6 and Manufacturing Readiness Level 6. In addition, a functional radar prototype, with hardware and software components representative of the technology in the final design, will demonstrate the maturity of these technologies.