Raytheon Co. has submitted an unsolicited bid to the U.S. Air Force in a quest to win the prime contract for a proposed Space Radar demonstration that would launch in 2008, according to company officials.

Winning that contract could lead the two teams vying to build the operational Space Radar to reconsider their decisions to use a radar sensor supplied by Northrop Grumman Electronic Systems, said David Shingledecker, vice president and general manager of strategic systems for Raytheon Space and Airborne Systems of El Segundo, Calif. Raytheon hopes to build the radar sensor for the operational satellites, which are slated to begin launching around 2015 assuming program approval by Congress.

The proposed Space Radar demonstration would entail two quarter-scale satellites. Northrop Grumman Electronic Systems of Linthicum, Md., is angling for the lead role in the demonstration and has solicited information from potential spacecraft suppliers. Raytheon submitted its own bid March 24, Shingledecker said in an April 5 interview here at the National Space Symposium. He declined to say whether Raytheon has discussed its plans with the Space Radar prime contract hopefuls.

Northrop Grumman Space Technology of Redondo Beach, Calif., and Lockheed Martin Space Systems of Denver are competing against each other to build the operational Space Radar satellites.

The Space Radar satellites are envisioned as a tool for providing high-resolution imagery to intelligence users regardless of time of day or weather conditions while also helping the military detect moving targets on the battlefield.

The concept for the demonstration came from Northrop Grumman Electronic Systems, which submitted the idea to the Air Force shortly after Congress slashed funding in the service’s 2005 budget request last summer for what was then called the Space Based Radar program.

Northrop Grumman and the Air Force — and now Raytheon — believe the demonstration will help answer congressional concerns about the Space Radar program by reducing the technical risk prior to moving ahead with the construction of the full-scale satellites.

Neither Raytheon nor Northrop Grumman has been willing to publicly estimate the cost of the demonstration. The Air Force has requested $226 million for the Space Radar in 2006, and a significant portion of that sum would go toward the demonstration mission, according to service officials.

While Northrop Grumman Electronic Systems has touted its experience in building radar sensors for military aircraft to make its case for leading the demonstration, Raytheon is pointing to its work on military and intelligence ground systems to support its proposal.

Michael Gross, Raytheon director of radio frequency space programs, said the Space Radar satellites’ ability to plug into existing ground systems will be a key task for the demonstration, and is just as important as designing the radar payload components.

Meeting the 2008 launch date for the demonstration is challenging but achievable, if a contract is awarded by October, Gross said.

Like Northrop Grumman Electronic Systems, Raytheon would choose a subcontractor to build its satellite platforms if it wins the demonstration contract, and has already received proposals from potential providers . Shingledecker declined to name the companies.

Northrop Grumman’s request for information drew six bids: Ball Aerospace, Boulder, Colo.; Orbital Sciences Corp. of Dulles, Va.; Swales Aerospace of Beltsville, Md.; General Dynamics’ Spectrum Astro Space Systems of Gilbert, Ariz.; Microsat Systems of Littleton, Colo.; and Space Systems/Loral of Palo Alto, Calif.

Some congressional aides said they were pleased to see that the Air Force has options for the Space Radar demonstration, and that the service could help its case for the program on Capitol Hill if it gives Raytheon serious consideration.

However, Congress has looked skeptically at the concept in the past, killing a previous plan for a two-satellite demonstration in 2000. Funding for the demonstration in the 2006 budget is by no means a certainty, aides said.