The US Department of Homeland Security is to experiment with the use of high-altitude long-endurance UAVs to protect commercial aircraft against Manpads missile attacks during take-off and landing at major US airports.

A technical demonstration is expected during the US 2008 financial year, with contract awards expected in mid-August. As an intermediate step, however, the DHS plans to carry out a sensor risk-reduction trial aboard either a General Atomics MQ-9 Predator B or Northrop Grumman RQ-4 Global Hawk by October.

The technical assessment programme, designated Project Chloe, follows US congressional directives for the DHS to explore multiple approaches to the protection of commercial aircraft from Manpads missile attacks in parallel to existing work on fitting airliners with directed infrared countermeasures systems. The project has a current budget of $12.7 million.

According to broad agency announcement documents issued on 27 March, the project is intended to “evaluate, develop as required, and demonstrate at the prototype or critical technology level an alternative concept of providing persistent stand-off airborne Manpads protection for all commercial aircraft within a designated geographic area.

“This effort will couple proven high-altitude endurance unmanned aerial systems with counter-Manpads technology solutions that prove to be the most promising in defeating the Manpads threat to commercial aviation.”

Two technical approaches are expected. The first would see all missile warning sensor systems and countermeasures equipment placed aboard one or multiple HALE UAVs that would orbit above an airport at 60,000ft (18,300m) providing continuous surveillance and protection.

The second would see a HALE UAV operating in co-operation with a network of missile warning sensors and countermeasures deployed either on the ground or aboard other aircraft.

The core requirement is for the system to be able to “protect aircraft within the air space bounded by the threat envelope (defined as a 3 mile [4.8km] radius around each aircraft operating at or below 18,000ft AGL) applied to standard approach and take-off corridors of commercial aircraft nominally extending up to 65 miles from airports (along all flight paths)”.

Key airports to be studied in the assessment phase are Denver, Las Vegas, Los Angeles, Newark, San Diego and Washington’s Reagan National.

Depending on opportunities during the demonstration phase, the DHS is also signalling that it may use UAVs involved in the programme to demonstrate other missions such as aerial communications relay for emergency services and border patrol.

As well as General Atomics and Northrop Grumman other contenders for the project are expected to include Aerovironment and Aurora Flight Sciences. Initial responses close on 25 April with full proposals due on 8 June. Project start is targeted for mid-September, or one month after contract signature.

The sensor risk reduction trial later this year will see modification of “an existing prototype two-colour infrared missile warning sensor and demonstrate Manpads detection and warning capability from high altitude and long range. The goal is to demonstrate this on a Department of Defense Global Hawk, DHS Predator B, or manned surrogate by late FY2007 to establish baseline capability of that technology in the Chloe operating environment. Data and analysis from this effort should be available to offerers selected under this broad agency announcement sometime in late FY2007.”