An Acoustically Controlled Tetherless Underwater Vehicle for Installation and Maintenance of Neutrino Detectors in the Deep Ocean

179 An Acoustically Controlled Tetherless Underwater Vehicle for Installation and Maintenance of Neutrino Detectors in the Deep Ocean--Deep Ocean Engineering, 1431 Doolittle Drive, San Leandro, CA 94577-2225; (510) 562-9300 Dr. Phillip J. Ballou, Principal Investigator Mr. Dirk D. Rosen, Business Official DOE Grant No. DE-FG03-97ER82356 Amount: $74,987 One of the methods that DOE supports in the detection of high energy neurinos requires the installation and servicing of detectors in the deep ocean from a surface support vessel. However, conventional tethered systems are problematic. A one kilometer squared grid array of 50 meter-spaced of multiple detector strings rising 500 meters from the ocean floor presents a substantial entanglement hazard for equipment cables deployed from the surface. Such tasks may be accomplished with fewer risks using a tetherless underwater remotely operated vehicle. A local acoustic telemetry link can be used to send control commands and sensor data between the vehicle and a stationary hydrophone suspended above or just outside the perimeter of the work site. Phase I effort of this project will develop an underwater acoustic telemetry link for vehicle control and sensor feedback, evaluate video compression methods for real-time acoustic transmission of video through the water, and define local control routines for use on board the vehicle to allow it to perform certain basic maneuvering tasks autonomously as well as initiate a self-rescue if the acoustic control link should be lost. In Phase II, a prototype tetherless vehicle system will be designed and constructed to demonstrate the ability to install cable interconnections within a detector array at 4 km depth. The same control technology could be used with a larger more powerful vehicle to maneuver the detector strings into desired positions as they are being lowered to the ocean floor. Commercial Applications and Other Benefits as described by the awardee: A tetherless remotely operated vehicle offers distinct commercial advantages over tethered systems. Elimination of the umbilical cable, with its intrinsic drag and entanglement hazards, allows much smaller, lower-powered, and less expensive vehicles to be used at greater speeds and longer excursion distances from the deployment vessel. Possible applications include mapping of the ocean floor, search and recovery operations, military mine countermeasures, and deep water drilling support.