Raytheon will soon stage a demonstration of a system for launching an unmanned air vehicle from underwater, moving a step closer to follow-on tests using a submerged submarine.

US Navy submarines move relatively freely under the surface, but have limited vision at periscope height, says Jeff Zerbe, Raytheon programme director for the submarine over the horizon organic capabilities effort. For example, the top masts of an aircraft carrier could probably be detected by periscope from a distance of 20km (10.8nm), but the submarine would be unlikely to positively identify the vessel.

The ability to launch a disposable unmanned aircraft from underwater could dramatically extend a submarine's visual range for surface contacts, says Zerbe, a former USN submarine commander.

About four years ago, Zerbe and Raytheon engineering fellow Dave Bossert proposed how to operate UAVs from a submarine. The small aircraft, equipped with sensors and communications links, are loaded into a waste disposal tube which can be ejected into the water. This floats to the surface and stabilises at a 30° angle before the UAV is launched.

The host submarine could directly control the aircraft from underwater or allow it to fly autonomously, only receiving sensor and communications updates from its free-roaming aerial sensor.

Raytheon has designed the UAV to be a disposable asset, both in terms of engineering and price, Zerbe says.

The first demonstration of the system took place on 10 September, when two surface launch vehicles were submerged to 24m (80ft) and allowed to float to the surface. The next will come within a few weeks, and demonstrate a full-up aircraft launch. After that event, Raytheon plans to reveal the identity of its selected UAV and aircraft supplier. The company confirms the aircraft's ground control system is compatible with the Swift Engineering blended wing Killer Bee design: the Raytheon/Swift team's offering for the proposed USN/US Marine Corps small tactical unmanned aircraft system/Tier II contract.

A follow-on test is planned next year to demonstrate the entire system, including the ejection from the submarine's waste disposal unit. Raytheon expects this to be followed by a series of user assessments, giving the submarine community time to become comfortable with the tactics for operating their own UAVs.

Source: Flight International