The clock is running out for Raytheon to declare whether it is protesting its loss of a contract to Lockheed Martin to build the U.S. Air Force’s new space surveillance radar.

The U.S. Air Force briefed Raytheon on its loss on June 9, and the company has 10 days to protest with the Government Accountability Office.

The $915 million contract was awarded to Lockheed Martin on June 2. Lockheed Martin officials have already begun work in the project, according to company spokeswoman Rahsi Ratan.

The contract includes placement of a large, S-band radar at the Kawjalein Atoll near the equator in the Marshall Islands. A second site, for which funding has not been provided, includes another radar in Western Australia.

The program aims to replace the defunct Space Fence that included radars across the U.S. The new Space Fence will be a radar complement to the Pentagon’s space surveillance network, which tracks objects in space in an effort to avoid collisions. The new radar, which is slated for operations in 2018 (52 months after contract award) will be able to detect 5-cm-dia. objects – far smaller than those detectable with today’s system.

The new radar will be coupled with other space surveillance systems, such as terrestrial telescopes and the Space-Based Space Surveillance system, a telescope already in orbit. The Air Force is slated to launch the first two Geosynchronous Space Situational Awareness Program (GSSAP) satellites on July 23 from Cape Canaveral, Florida. They were developed in secret but unveiled by Air Force Space Command chief Gen. William Shelton in February. They will surveil satellites in geosynchronous orbit, but the Air Force has not specified the satellites’ payloads.

The Space Fence contract was to be awarded last year but was delayed by Air Force concerns over affordability due to sequestration.