Robot Vehicle Surveys Deep Sea Off Pacific NorthwestAugust 14, 2008The first scientific mission with Sentry, a newly developed robot capable of diving as deep as 5,000 meters (3.1 miles) into the ocean, has been successfully completed by scientists and engineers from the Woods Hole Oceanographic Institution (WHOI) and the University of Washington (UW). The vehicle surveyed and helped pinpoint several proposed deep-water sites for seafloor instruments that will be deployed in the National Science Foundation (NSF)'s planned Ocean Observatories Initiative (OOI). Sentry is a state-of-the-art, free-swimming underwater robot that can operate independently, without tethers or other connections to a research ship.
The autonomous underwater vehicle, or AUV, is pre-programmed with guidance for deep-water surveying, but it can also make its own decisions about navigation on the terrain of the seafloor. "This investment into emerging technologies is paying off in delivering state-of-the-art science support," said Julie Morris, director of NSF's Division of Ocean Sciences. "In the near future, Sentry will conduct high-resolution oceanographic surveys that would be otherwise impossible." Working in tandem with sonar instruments on the UW-operated research vessel Thomas G. Thompson and with photo-mapping by WHOI's TowCam seafloor imaging system, Sentry gathered the most precise maps to date of seafloor features known as Hydrate Ridge and Axial Volcano off the coast of Oregon and Washington. "We are changing the way ocean science is done, launching a new era in which an ensemble of technologies will provide us with an increasing capacity for exploring and interacting with the global oceans," said John Delaney, chief scientist of the expedition and principal investigator for the UW-led regional observatory in the planned OOI. The one-of-a-kind, WHOI-built AUV--which was largely funded by NSF--made six dives during the July 22 to August 5 expedition. Sentry surveyed 212 linear kilometers of seafloor, or about 53 square kilometers, as it traced parallel lines like a lawn-mower making a pattern across a yard. "Sentry had a very successful introduction," said Dana Yoerger, the lead WHOI engineer for the vehicle. "We had tested the AUV as best we could before we got out here, but the steep terrain of the deep sea is quite a different matter." The AUV can collect the data needed to make seafloor maps at a resolution of less than one meter. On this first cruise, Sentry collected as many as 60 million individual soundings of seafloor depth in a single dive. Powered by more than 1,000 lithium-ion batteries-similar to those used in laptop computers, though adapted for extreme pressures, Sentry dove for as long as 18 hours and 58 kilometers, with the potential for longer trips in the future. Sentry is designed to swim like a fish or fly like a helicopter through the water. The sleek hydrodynamic design allows the vehicle to descend quickly from the sea surface to the depths (about 3,500 meters per hour). The novel shape also gives the vehicle tremendous stability and balance while cruising through bottom currents. The vehicle has thrusters built into its foils, or wings. Like an airplane, the foils allow the vehicle to gain lift or drag or directional momentum, as needed. When necessary, the AUV also can hover over the bottom for close-up inspections, navigational decision-making, and for rising up and down over rugged seafloor terrain. The design allows the vehicle to start, stop, and change directions, whereas many AUVs tend to travel in one direction. The AUV steers itself with a magnetic compass; long-baseline (LBL) navigation triangulated from underwater beacons; a sophisticated inertial guidance system (INS); and, when within 200 meters of the bottom, an acoustic sensor that can track the vehicles' direction and speed with incredible precision. "Sentry is a true robot, functioning on its own in the deep water," said Rod Catanach, a WHOI engineer who works with Sentry. "The vehicle is completely on its own from the time it is unplugged on the deck and cut loose in the water." With this mission successfully completed, Sentry is now ready to join the National Deep Submergence Facility (NDSF), a federally funded center based at WHOI that operates, maintains, and coordinates the use of vital deep ocean vehicles for the U.S. oceanographic community. Sentry will replace the Autonomous Benthic Explorer (ABE), Sentry's predecessor in the NDSF and a pioneer in deep-diving vehicle operations since 1996. Eventually, vehicles like Sentry and its successors will plug into and interact with the ocean observatory system, using the power charging systems and high speed communications delivered by the submarine networks. Funding for the development of Sentry also was provided by the Russell Family Foundation, WHOI's Deep Ocean Exploration Institute, the Comer Science and Education Foundation, and WHOI's Access to the Sea program. Funding for the OOI mapping cruise was provided by NSF through the Consortium for Ocean Leadership; by Arizona State University; and by the UW School of Oceanography. The National Science Foundation (NSF) | |||||||||||||||||||||
|
Related Oceanographic Current Events and Oceanographic News Articles A new approach in tsunami-early warning The newly implemented Tsunami Early Warning System for the Indian Ocean, GITEWS, goes into operation today and with this, the system enters its final phase of optimisation. Deep sea expedition sets sail Setting sail on the Pacific, a University of Delaware-led research team has embarked on an extreme adventure that will find several of its members plunging deep into the sea to study hydrothermal vents on the ocean floor. Coral reefs found growing in cold, deep ocean Imagine descending in a submarine to the ice-cold, ink-black depths of the ocean, 800 metres under the surface of the Atlantic. NASA study finds rising Arctic storm activity sways sea ice, climate A new NASA study shows that the rising frequency and intensity of arctic storms over the last half century, attributed to progressively warmer waters, directly provoked acceleration of the rate of arctic sea ice drift, long considered by scientists as a bellwether of climate change. Study reveals an oily diet for subsurface life Thousands of feet below the bottom of the sea, off the shores of Santa Barbara, single-celled organisms are busy feasting on oil. May 2008 earthquake in China could be followed by another significant rupture Researchers analyzing the May 2008 Wenchuan earthquake in China's Sichuan province have found that geological stress has significantly increased on three major fault systems in the region. Arctic ice on the verge of another all-time low Following last summer's record minimum ice cover in the Arctic, current observations from ESA's Envisat satellite suggest that the extent of polar sea-ice may again shrink to a level very close to that of last year. New robot scouts best locations for components of undersea lab Like a deep-sea bloodhound, Sentry - the newest in an elite group of unmanned submersibles able to operate on their own in demanding and rugged environments - has helped scientists pinpoint optimal locations for two observation sites of a pioneering seafloor laboratory being planned off Washington and Oregon. Geologists discover signs of volcanoes blowing their tops in the deep ocean A research team led by the Woods Hole Oceanographic Institution (WHOI) has uncovered evidence of explosive volcanic eruptions deep beneath the ice-covered surface of the Arctic Ocean. Fire under the ice An international team of researchers was able to provide evidence of explosive volcanism in the deeps of the ice-covered Arctic Ocean for the first time. More Oceanographic Current Events and Oceanographic News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||