Tethered Aerostat Radar System

The [http://www.af.mil/factsheets/factsheet.asp?fsID=3507 Tethered Aerostat Radar System] is a low-level surveillance system that uses aerostats as radar platforms. Another system of this kind is the EL/M-2083.

System

The aerostats are large fabric envelopes filled with helium, and can rise up to an altitude of convert|15000|ft|m|-2 while tethered by a single cable. The largest lifts a 1000 kg payload to an operating altitude providing low-level, downward-looking radar coverage. The aerostat consists of four major parts or assemblies: the hull and fin, windscreen and radar platform, airborne power generator, and rigging and tether.

The hull of the aerostat contains two parts separated by a gas-tight fabric partition. The upper chamber is filled with helium and provides the aerostat's lifting capability. The lower chamber of the hull is a pressurized air compartment. The hull is constructed of a lightweight polyurethane-coated Tedlar fabric. An airborne engine drives the generator, supplied by a 100-gallon diesel fuel tank.

Operation

Operators launch the aerostat from a large circular launch pad containing a mooring fixed or mobile system. The mooring systems contain a large winch with 25,000 feet of tether cable. Operational availability is generally limited only by the weather (60 percent standard) and routine maintenance downtime. The aerostats are stable in winds below convert|65|kn|km/h|0. Aerostat and equipment availability averages more than 98 percent system-wide.

For security and safety reasons, air space around Air Force aerostat sites is restricted for a radius of at least two to three statute miles and an altitude up to convert|15000|ft|m|-2.

Mission

The primary mission is to provide low-level radar surveillance along the southwest border of the United States and Mexico, the Straits of Florida and the Caribbean in support of federal agencies involved in the nation's drug interdiction program. The secondary mission is to provide North American Aerospace Defense Command with low-level surveillance coverage for air sovereignty in the Florida Straits. The aerostat radar data is available to NORAD and U.S. Customs and Border Protection.

History

The first aerostats were assigned to the Air Force in December 1980 at Cudjoe Key, Fla. During the 1980s, the U.S. Customs Service operated a network of aerostats to help counter illegal drug trafficking. Their first site was built at High Rock, Grand Bahamas Island, in 1984. The second site was built at Fort Huachuca, Ariz., in 1986. Before 1992, three agencies operated the TARS network: the Air Force, U.S. Customs Service and U.S. Coast Guard. Congress in 1992 transferred management of the system to the Defense Department, with the Air Force as executive agent. Under Air Force management, through contract consolidation and system standardization, the operations and maintenance cost per site was reduced from $6 million in fiscal year 1992 to $3.5 million in 2007.

Technical and operational data

Primary Function: Low-level, downward-looking radar; aircraft detection

Volume: 275,000 and 420,000 cubic feet

Tether Length: convert|25000|ft|m|-2

Payload Weight: 1,200-2,200 pounds

Maximum Detection Range: convert|200|nmi|km|-2

Operational Sites: Yuma and Fort Huachuca, Ariz.; Deming, N.M.; Marfa, Eagle Pass, and Rio Grande City, Texas; Cudjoe Key, Fla.; and Lajas, Puerto Rico. Sites located at Morgan City, La., and Matagorda, Texas, are in a cold-storage configuration. Contract management office and logistics hub are located in Chesapeake, Va.

ee also

*Measurement and Signature Intelligence