WASHINGTON — The U.S. Defense Advanced Research Projects Agency (DARPA) awarded Orbital Sciences Corp. a sole-source contract worth $74.6 million to continue developing a distributed, or fractionated, satellite architecture, according to a Dec. 4 posting on the Federal Business Opportunities Web site.

Dulles, Va.-based Orbital in February 2008 beat out five competitors to win a contract for the first phase of DARPA’s F6 satellite development program. The project aims to demonstrate the ability to fly multiple satellites in a close formation that would communicate wirelessly with one another, and perform like a single integrated spacecraft. Orbital previously received contracts totaling $13.6 million for the program.

Under the one-year, cost-plus-fixed-fee Phase 2 contract, Orbital will further define its concept and complete a critical design review of the spacecraft architecture, the posting said. In a document justifying the use of a sole-source contract, DARPA said Orbital is the only company with the requisite capabilities, facilities and experience to do the job, and choosing a new contractor would require at least $10 million to duplicate work that Orbital has already done.