When launched in 2010, a five-plus-ton demonstrator radar antenna the length of a football field will serve as the forerunner for the future of U.S. intelligence, surveillance and recon assets in space. It has a few hurdles before detecting ground targets from the cosmos, though.

A demonstrator radar antenna not often written about is said to serve as the forerunner for the future of America’s intelligence, surveillance and reconnaissance assets in space when it is launched in 2010. The radar antenna, weighing more than five tons, will be the length of a football field.

The innovative space-based radar antenna technology (ISAT) program, administered by the Air Force Research Laboratory’s Space Vehicles Directorate (AFRL/VS), concentrates on developing systems to deploy “extremely large (up to 300 yards) electronically scanning radar antennas flying 5,700 miles above the Earth’s surface and providing improved ground target detection to the warfighter,” according to the AFRL/VS.

Says Dr. Steven A. Lane, ISAT program manager, in a recent Air Force news article:

These huge antennas will enable the revolutionary performance required to conduct tactical sensing from space, including missions like continuous and reliable tracking of surface targets.

The antenna uses radar, so it is not limited by cloud coverage. And unlike optical systems, it can operate at night.

Originated in 2002, the ISAT program is sponsored by the Defense Advanced Research Projects Agency (DARPA), which has designated the AFRL/VS to execute the ISAT Demonstration System flight experiment program. In a realistic space environment (specific orbit based on proposals received), the ISAT flight demonstration system will demonstrate the key risk reduction technologies considered critical to the development and fielding of an objective Space-Based Radar (SBR) system capable of providing tactical-grade Ground Moving Target Indication (GMTI) from a medium Earth orbit (MEO).

Simply put, the objective of the multimillion-dollar project is to create and demonstrate technology for “very long space-borne electronically scanning antenna,” assisting the warfighter through development of tactical-grade, ground-moving target identification capability, according to GlobalSecurity.org. The ISR tool will enable targets to be tracked and indentified with precise resolution and scanning in multiple areas of interest.

The demonstration experiment will use an antenna extending about 325 ft. in length, while the full-scale version is designed to extend three times that. Further, the full-scale antenna payload would be folded up to about the size of a sport utility vehicle (SUV) and placed inside a payload fairing atop the launch vehicle. Once deployed in space, the antenna’s length would be “similar to the height of the Empire State Building.”

Such a lightweight and lengthy antenna could significantly increase persistent surveillance coverage, observes GlobalSecurity.org.

Key technologies to be developed and demonstrated on the ISAT flight experiment include space-capable structural materials, mechanisms for the deployment and control of large apertures, and calibration and compensation across structures several hundred meters in length for coherent transmit beam forming.

In addition to DARPA’s Special Projects Office and the AFRL/VS, the ISAT program also involves participation by the laboratory’s sensors directorate at Wright-Patterson AFB (Ohio), information directorate at Rome Laboratory (N.Y.), NASA’s Langley Research Center (Langley, Va.) and Jet Propulsion Laboratory (Pasadena, Calif.). As well, two contractor teams — Boeing Co. and Raytheon Co; and Lockheed Martin Corp. and Harris Corp. — are competing to build the 100-yard-sized flight experiment. After the spacecraft’s critical design review process next month (June), DARPA will select one of the two contractor teams to advance the project, with recommendations from the space vehicles directorate.

Before the planned Cape Canaveral, Fla. liftoff occurs in four years, though, the ISAT spacecraft must be “developed, integrated and tested at the contractor facility,” says the Air Force Research Library’s ISAT fact sheet.

Notes Air Force news:

Because of the antenna’s large size, which prevents ground testing of the integrated system before launch, there is an unprecedented emphasis on modeling, simulation and ground-based risk-reduction demonstrations. These will play a crucial role in the flight experiment’s outcome.

As such, the ISAT team has concentrated on four specific areas of the project: structures, radar, metrology and calibration — as well as engineering, integration and testing.

Ultimately, all involved in the program hope ISAT will provide a solution to the challenge of integrating space-based radar and a moving-target indication from space.

Resources

Air Force Research Library’s ISAT fact sheet
Air Force Research Laboratory’s Space Vehicles Directorate (AFRL/VS)

Big leap forward in detecting ground targets from cosmos
by Michael P. Kleiman
Air Force Link, March 1, 2006

Space Based Radar (SBR), Innovative Space Based Radar Antenna Technology (ISAT)
GlobalSecurity.org