Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.
Issue link: https://insideunmanned.epubxp.com/i/470284
38 unmanned systems inside Spring 2014 core, shielded from seawater by a thin coating of plastic, is a specially designed glass fiber similar to those used by communications companies. The 250 micrometer cable is so light it is nearly neutral in seawater. It floats with the currents as it is rolled out from two canisters, each about the size of a large coffee can, located between the sup- port ship and the Nereid. Built with support from the National Science Foundation, the system will greatly expand the range of underwater craft operating in ice-cov- ered areas. "Conventionally tethered [remotely operated vehicles] may be restricted in their placement," the research team wrote in the syn- opsis of its NSF award, "as the ice-resistant re- search ships from which they are deployed may be forced to drift with migrating ice over distanc- es of >1 km in a matter of hours while over-the- side operations are underway." The tether is also vital to the operation of the second member of the Nereid family—the Nereid 11km, a deep-diving craft being built for the Schmidt Ocean Institute. Once com- pleted, the Nereid 11km will join the Nereus as one of only three vehicles able to operate in the ocean's hadal depths—from 6,000 meters down to the ocean f loor. The Nereus, the predecessor to the Nereid design and also a Woods Hole vessel, dove into Challenger Deep in the Pacific Ocean's Mari- ana Trench in May 2009, successfully reaching the ocean's deepest known point some 11 km down. To make the trip back from the trench possible, Woods Hole engineers stuffed nearly 1,600 pressure-resistant ceramic spheres into the hulls of the craft's twin compartments to give it the buoyancy needed to maneuver up to its support ship. Where the Nereus had spheres for buoyancy the Nereid 11km will use a block of patent- pending foam attached to the ship. Such foam, which is laced with tiny glass spheres for lift, is used in other types of underwater craft. The Nereid's foam was originally developed for the Deepsea Challenger, the world's third hadal- capable system, and actually formed part of that vessel's structure. Explorer James Cam- eron made a record-breaking solo dive with the vehicle into the Challenger Deep in March 2012. The improved version of the foam now avail- able uses a different kind of glass spheres and a different type of resin, said Loral O'Hara, a research engineer at Woods Hole and the tech- nical lead for the Nereid 11km project. The way the foam is mixed is key, she said. The spheres must be distributed evenly so the foam does not crack as it contracts and expands during a mis- sion to and from a high-pressure region. O'Hara said her team is talking to two companies for the foam—Engineered Syntactic Systems of Attle- boro, Mass., and Ron Allum Deepsea Systems of St Peters New South Wales in Australia. En- gineer Ron Allum was part of the Deepsea Chal- lenger team. The Nereid 11km will be able to use the glass- core tether and three other kinds of communica- The Nereid Under Ice, the newest vehicle from the Woods Hole Oceanographic Institution's Deep Submergence Laboratory, undergoes tests in a pool at the Coastal Research Lab. MARINE Photos courtesy of Tom Kleindinst, Woods Hole Oceanographic Institution