Both Raytheon [RTN] and Lockheed Martin [LMT] completed their preliminary design review (PDR) contracts for the Air Force’s Space Fence program.

Lockheed Martin spokesman Chip Eschenfelder said Friday was the Air Force’s contract end date, which began in January 2010 with a pair of $107 million contracts. Raytheon announced its PDR contract completion Friday in a statement.

Lockheed Martin said in March it had a working prototype. Raytheon spokeswoman Michele Lemos said in an email Friday the company successfully demonstrated its prototype in January.

During the Space Fence PDR program, the Air Force evaluated cost, schedule, the maturity of technology and design in support of transitioning the system into production, Raytheon said in a statement.

Eschenfelder said the next step is anticipated release of the Request For Proposals (RFP), which he said should happen in the next couple of months.

Space Fence is a program to improve the way the United States detects, tracks, measures and catalogs orbiting objects and space debris with improved accuracy, better timeliness and increased surveillance coverage, Lockheed Martin said in a statement. The United States operates a worldwide network of ground radars for space tracking, but the country’s ability to monitor objects orbiting over the Southern hemisphere is quite limited, according to experts.

The legacy system is called the Air Force Space Surveillance System and comprises three Very High Frequency radar transmission sites and six receive sites spread across the southern United States. It has been in service since the early 1960s.

Space Fence is a multi-phase acquisition program, leading to the delivery of up to two, globally positioned S-band radars operating in the U.S. Space Surveillance Network.

The total cost of Space Fence is expected to be around $3 billion (Defense Daily, Jan. 28, 2011). Eschenfelder said initial operational capability for Space Fence is expected by 2017.