Defence

Northrop Grumman has unveiled proposals to launch unmanned air vehicles from submarines by modifying the vertical launch encapsulation system currently used to launch Raytheon Tomahawk cruise missiles.

The modified stealthy affordable capsule system (SACS) would draw on Northrop's work in support of two October 2004 test launches of its miniature air-launched decoy from the US Navy's Ohio-class submarine USS Georgia.

A trial submerged launch of a Raytheon AIM-9X Sidewinder air-to-air missile using a development of the capsule is planned for next March, with launch from a submarine planned for the fourth quarter of 2007.

Northrop is also flagging the AGM-114 Hellfire air-to-surface missile as a candidate for the encapsulation system, and displayed mock-ups of all three SACS-housed missiles during the Association for Unmanned Vehicle Systems International's Unmanned Systems North America exhibition in Orlando, Florida last month.

Northrop says the SACS design could be used to launch a variety of fixed-wing UAVs by using "clamshell" opening techniques after it leaves the water. A UAV variant could use gas overpressure or rocket boosters to provide flight velocities once the capsule opens, it says.

Other launch concepts include deploying free-floating or bottom-resting SACS capsules from a submarine or surface vessel. These would be activated remotely or by a tripwire to launch a UAV to conduct surveillance. Preliminary work has also been carried out on a 21in SACS version for use in standard NATO torpedo tubes.

Northrop has held discussions with a number of UAV manufacturers about the concept, which it says could lead to fielded equipment within 18 months. It is not, however, involved in Lockheed Martin's Cormorant submarine-launched UAV concept.