Lockheed Martin released an interesting video on their Cormorant submarine launched MPUAV (Multi-Purpose Unmanned Aerial Vehicle) program. That’s right, submarine launched. This program was funded by DARPA and was actually cancelled back in 2008 due to budget cuts, but it is still interesting. I don’t think I’d even seen video of the design before, though this video is dated 2008. The idea came from trying to find new uses for the US Navy’s SSBNs (aka missile subs). Under arms reduction treaties the US Navy has four Ohio class SSBNs which must no longer carry SLBMs (Submarine Launched Ballistic Missiles), but which have plenty of service life left.
Several concepts were floated, and in the end it was decided to convert these four boats into SSGNs, carrying up to 154 Tomahawk cruise missiles instead of the 24 Trident ballistic missiles. 22 of the missile tubes have been retrofitted with a vertical launch system that can hold up to seven Tomahawks each, or other ordinance (7 x 22 = 154). The other two tubes have been converted into swimmer lockout chambers for the deployment and recovering of SEAL teams.
One of the concepts for the missile tubes was for a submarine launched UAV which could support special warfare operations, perform reconnaissance and targeting, etc. The missile tubes are 44 feet long, but only seven feet in diameter. This necessitated creating a folding design so the UAV could be packed into the tube yet still have enough wing area. Since a submarine’s greatest asset is stealth the UAV needed to be launched while the sub remained submerged. This required a design that was water tight – including the engine, corrosion resistant – salt water after all, and crush resistant – lots of force from the water pressure at launch depth.
Lockheed Martin’s design features an oddly cranked wing which gives the Cormorant more wing area while keeping for a compact size while folded. For launch the MPUAV would have been raised from the tube, then unfolded and released to rise to the surface under natural buoyancy while the sub slipped away. The MPUAV would pop clear of the surface like a cork and rocket boosters would propel it into the sky. Once clear of the water the engine inlet and exhaust doors would open and the turbofan engine would fire to sustain flight.
At the completion of its mission the Cormorant would have flown back to a rendezvous location, sealed itself back up, and parachuted into the water. A remotely operated vehicle (ROV) would swim up from the sub with a cable and attach it to a cable deployed from the MPUAV upon landing. The MPUAV would then be winched back to its cradle and stowed back in the tube.
It is a very clever and unique design, and under the DARPA program they build models and testing the launch and recovery procedure. It is all pretty interesting stuff, and seen in the video. Check it out:
