Press Release

Robots Powered by the Ocean Itself

By SpaceRef Editor
October 10, 2002
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They call them "gliders," but these move through water instead
of air. Two new robotic gliders – autonomous underwater vehicles
– powered by changes in their own buoyancy or by different temperature
layers in the ocean – will be tested operationally in Navy and Marine
Corps exercises off Southern California during 2003. Both gliders were
developed with support from the Office of Naval Research.

Webb Research of East Falmouth, MA, a company with long experience designing
and building oceanographic instruments, will deploy its Slocum Glider
during the exercise. The Slocum Glider uses a Webb Research heat engine
that draws energy from the ocean thermocline – a layer where the
ocean’s temperature changes rapidly: it’s the boundary between the warmer
water above and the cooler waters below. The Slocum Glider cycles thousands
of times between the surface and a programmed depth, getting the energy
it needs to change its buoyancy from the heat flow of the surrounding
water. This long-range deep ocean glider is designed to cruise for five
years in a vertical zig-zag from the surface to depths of about 5,000
feet and back. As it does so it measures salinity and temperature, plots
currents and eddies, counts microscopic plants, and even records "biological"
sounds like whale songs. An earlier battery powered model is used to study
coastal waters up to 656 feet in depth for up to 30 days at a time. Webb
Research named the glider in honor of Captain Joshua Slocum, who sailed
alone around the world in a 37 foot sloop between 1895 and 1898.

The second robot – the University of Washington Applied Physics
Laboratory’s Seaglider – is propelled by buoyancy control and wing
lift to alternately dive and climb along slanting glide paths. It dead
reckons underwater between Global Positioning System (GPS) navigation
fixes it obtains at the surface, and so glides through a sequence of pro-grammed
waypoints. It transmits data and receives commands via satellite data
telemetry when it exposes an antenna above the sea surface for a few minutes
between dive cycles. Seaglider has enough range to cross an entire ocean
basin in missions that last months, all the while diving and rising between
the surface and waters as deep as 3500 feet. It can be launched and recovered
manually from a small boat with a crew of two, and so doesn’t rely on
costly ships for its deployment. Seaglider collects high resolution profiles
of physical, chemical, and bio-optical properties of the ocean.

The Office of Naval Research is interested in systems like Seaglider
and the Slocum Glider because they offer the Navy and Marine Corps potential
tools for collecting data about regions of the ocean necessary for mine
countermeasures and other tasks important to expeditionary warfare. The
Office of Naval Research will sponsor demonstrations of these and other
advanced mine countermeasures systems off the beaches of Camp Pendelton,
CA, during 2003. These systems represent advanced science and technology
being developed to detect, identify, and classify mines in shallow and
very shallow waters. They exploit recent advances in sensors (especially
lasers, sonar, and television-like imaging), robotics (the sensors are
installed on a variety of autonomous underwater vehicles – submarine
robots), networking, and signal processing. Developed by teams of government,
industry, and academic partners, the mine countermeasures technologies
offer the prospect of ultimately reducing or eliminating the need for
Sailors and Marines to enter the dangerous shallow waters just off shore
in order to clear mines in preparation for expeditionary operations.

Office of Naval Research
Corporate Communications Office
POC: John Petrik, [email protected],

SpaceRef staff editor.