April 27 (Bloomberg) -- Lockheed Martin Corp., the world’s largest defense contractor, received a $399.9 million order from the Defense Advanced Research Projects Agency to develop an airborne radar blimp, the Pentagon said on its Web site.

Lockheed and partner Raytheon Co. were awarded the contract for the Integrated Sensor Is Structure program, the Defense Advanced Research Projects Agency said in a separate news release. The companies will develop the scale model of a radar that would be about 6,000 square meters (7,176 square yards) in size and embedded in a blimp 6 miles above the earth, the statement said.

The so-called ISIS radar could track small missiles and unmanned aerial vehicles as far as 600 kilometers (373 miles) away, the statement said. Lockheed beat Los Angeles-based Northrop Grumman Corp. for the contract, Jan Walker, a spokeswoman for the research agency, said in an interview.

Bethesda, Maryland-based Lockheed and Waltham, Massachusetts-based Raytheon received $100 million initially and will get the remainder in phases to finish the project by March 2013, Walker said.

To contact the reporter on this story: Gopal Ratnam in Washington at gratnam1@bloomberg.net.

Last Updated: April 27, 2009 18:12 EDT