Eave-East: Your mission underwater is to hover . . .

Artoo-Detoo, ''Star Wars' '' lovable little robot with the winning personality, has a real-life cousin that is running some intriguing underwater missions of its own.

University of New Hampshire marine scientists are testing the feasibility of sending unmanned, untethered, computer-controlled ''autonomous vehicles'' (AVs) on dangerous deep-sea assignments at their facility on Diamond Island in Lake Winnipesaukee.

The idea is to develop AVs that simulate intelligence and to dispatch them to perform vital underwater tasks in the ocean in order to save divers' lives and the hazards that such work sometimes entails. This technology is in its infancy, but it is rapidly catching the imagination of the international community of ocean scientists.

Most offshore work, such as oil drilling, is going on at depths less than 1, 000 feet. But the trend now is toward deeper water. As operations move out into more treacherous areas, unmanned vehicles will become increasingly essential.

Eave-East, UNH's experimental vehicle, is an open-framed, three-foot cube of aluminum pipes, with motors and tiny propellers that make it swim here and there on command. Designed to perform inspection tasks, the robot can move up, down, forward, backward, and sideways. It turns, rolls, pitches, and hovers. It pokes around and investigates things like a crab.

This fall it was plunged into and pulled out of the lake on one assignment after another. All tests of its component systems were successfully completed before oncoming winter laid the season's first glaze of ice on the lake. Tests of the total system are scheduled to resume in spring and be completed next summer.

Two years ago the vehicle's Mission I was simple and straightforward. Students and staff at UNH's Marine -Systems Engineering Laboratory laid an irrigation pipe on the bottom of the lake to simulate an oil pipeline. Then they asked Eave-East to go find and follow it. This meant the robot had to sense what a pipeline was, locate it, trace it, and then come home. Team members swam alongside the robot to monitor and photograph its behavior.

Eave-East performed so swimmingly that it got on TV. New Hampshire's educational station , Channel 11, ran excerpts from a 10-minute color movie the lab made of the robot going through its paces.

Mission II, now under way, is three dimensional and much more sophisticated. It is an attempt to develop a system that will enable the vehicle to inspect underwater structures.

When dumped into the lake, Eave-East's on-board computer commands it to find a 30-foot-high temporary structure of pipes that engineers have lashed together and set up on the lake bottom to simulate an oil-drilling rig.

The vehicle is told to go up through the structure, find an X painted on the side, and photograph it. After it has performed this little task, it must find its way out of the maze and back home to Diamond Island.

Although this experiment is not yet complete, Eave-East has again pleased its mentors with a high degree of ''smartness.''

Mission III, scheduled for the winter of 1982-83, will test its mettle even more. Slithering down through a hole in the ice, the vehicle will take off for seven miles (Winnipesaukee is 25 miles long). It is hoped that this time Eave-East will return from its foray with two maps in digital form - one of the lake floor, the other of the underside of the ice.

''If we put stronger batteries in it,'' says Arthur S. Westneat, an electronics consultant to UNH underwater projects, ''one of these automatons could venture forth on a round trip of 1,000 miles. In that mode it becomes a tool of exploration.''

These updates on Eave-East's derring-do were part of the program of Oceans ' 81, a conference sponsored annually by the Council of Oceanic Engineering of the Institute of Electrical and Electronics Engineers and by the Marine Technology Society. It is an international forum for presenting and discussing the newest oceanographic technologies. The theme of this year's conference, held in Boston, was ''The Ocean - an International Workplace.'' It drew some 1,000 ocean scientists and engineers from many countries, including Canada, Britain, France, Norway, and Japan.

In 1976 the conference heard its first paper on autonomous vehicles. This year AVs were a major focus, with five sessions and 20 papers devoted to this key topic - a measure of its growing importance.

The French described one AV that can operate at depths of up to 20,000 feet. It is now being used for deep bottom surveys of the Mediterranean.

Oddly, Mr. Westneat notes, ''We are unable to perform in our own environment - the great frontier of the ocean - as well as we do on remote planets. We see beautiful photographs coming back from many millions of miles away in outer space. But we still do not have unmanned machines that we can send down into the ocean and do our work for us. Yet the ocean is on our doorstep, part of our life. Here is where the wealth and potential are - minerals, petroleum, land for agriculture in the sea. Once we can explore our neighborhood environment, we're going to find things we want out there.''

Until a few years ago autonomous vehicles were inconceivable because there was no good way to build ''intelligence'' into them, Mr. Westneat explains. ''You couldn't keep in touch with your machine. As soon as it sank below the surface it was out of sight and contact. Our means of communication were ineffective.'' So no major attempt was made to get automated servants into the ocean.

The microchip revolution has made the unthinkable possible. . . . Now we are talking about computers compact enough to fit in your hand that we can put in small submersibles and send off to do sophisticated tasks,'' Mr. Westneat reports. ''With 'intelligence' in the vehicle, we can command it, control it, supervise its welfare, get it to sense and respond to its hostile environment. All the problems of living and operating in the ocean, the machine can do itself if it's smart enough. The growing ability to simulate intelligence is the foundation for all this development that is just starting.''

In the past, ocean scientists have been limited by their ability to make devices, he says. ''Now we are limited only by our imagination. That's a tremendous change in a human's life . . . . Now we have tools that allow us to achieve great progress.''

The group of scientists exploring the potential for doing jobs in the ocean through robots is small but growing. Of about 12 projects going on in universities and government agencies around the world, two-thirds of them are in the United States. As early as 1973 Massachusetts Institute of Technology students built a small submersible with a 20-mile range. From this beginning, MIT has built a three-pronged program of underwater robotics:

* MIT Profs. A. Douglas Carmichael and D. G. Jansson are now working on Robot II, a small torpedo-like search-and-survey autonomous vehicle 8 feet long and 13 inches in diameter which moves in a straight line, more like a fish than a crab. Its side-scan sonar produces a sound ''picture'' of the ocean bottom. Its designers think it will be useful in looking for lost ships, lost marine equipment, and deep v's on the underside of surface ice that could endanger oil drilling rigs. This contrasts with instruments which are towed or lowered from surface ships, such as those now searching for the Titanic.

* Prof. Thomas B. Sheridan, director of MIT's Man-Machines Systems Laboratory , is developing a sensing device and mechanical manipulators that are segmented like a human arm and hand to extend man's functions under water. The human being can be sitting in a ship somewhere and have sonar or TV cameras looking around under the water for him and have manipulators assemble machines, clean structures, operate valves, etc.

* Meanwhile MIT Prof. Arthur B. Baggeroer is cooperating with Woods Hole Oceanographic Institution to find ways to enable robots to transmit information from dangerous depths up to the man aboard ship.

One type of communication system being explored is acoustic telemetry, sending information through water by means of sound signals rather than by electromagnetic energy.

Fiber optics are also being tested. A lightweight fiber-optic cable is dropped overboard near the robot as a repeater station. Information is transmitted acoustically from the vehicle to the repeater station and from there by means of a laser beam traveling up the fine glass thread. This eliminates a heavy cable that would encumber the vehicle and perhaps entangle it in some underwater structure.

At times these experiments seem less like work and more like playing with clever toys. But everyone working on them is soberly aware of their tremendous potential for saving lives.

The Alexander L. Keilland disaster (in which 123 lives were lost in the icy waters of the North Sea March 27, 1980) alerted the entire oceanic community to the critical need to maintain safe offshore oil platforms.

In a 60-mile gale, one of the semisubmersible's five legs suddenly snapped off. The platform listed sharply, then turned turtle. Only 80 men were able to scramble to safety.

A Norwegian government inquiry into the disaster reported last April that metal fatigue had led to the fracture of a transverse stay, causing the collapse of one of the rig's five main supports. The report was critical of many aspects of the design, construction, and maintenance of the platform.

''These structures are dynamic, they move, they're subjected to fatigue stressing from continuous forces of wind and wave,'' explains Dr. Robert D. Collier, an ocean engineer with the consulting firm of ORI Inc. based in Silver Spring, Md., which is working on advanced development projects in underwater technologies.

''The technical issue,'' he says, ''is how to predict, design, and guard against failure due to fatigue of metal weldments. These welds are the critical zones where continuous cyclic stresses result in cracking that may lead to structural failure, a process that is not completely understood. So the need is to conduct an underwater inspection of these structures while they sit out there in the ocean.''

At present, inspection is done by divers when weather permits and is tremendously expensive, requiring a support vessel and crew for three weeks at a cost of more than $100,000. And that doesn't include the expense of repairing any damage found.

The anomaly is that the diver who inspects the structure usually does not have the engineering training that enables him to interpret what he finds. So he has to document his findings with photographs or other evidence so that engineers on the surface can assess what the evidence means.

Dr. Collier says one of the urgent needs of the offshore oil-drilling industry and the government agencies that regulate it is to develop well-defined requirements and specifications for structural inspection. Is a crack superficial or significant? Can you predict when a failure may occur? How often should a structure be inspected? Much money and effort ride on anwers to such questions.

The main technical challenge now, Dr. Collier says, is to give divers techniques and instruments they can use underwater with safety and confidence to detect structural flaws and cracks accurately.

Divers now use jets of water to blow off barnacles and get down to bright metal so they can make observations and take close-up color pictures.

They use magnetic particles to make inspections. Placing a magnet on the surface of the structure to create a magnetic field, they spray on a flux of material that sticks to the surface even under water and assumes a distribution pattern. If no crack is there, the pattern remains uniform. If there is one, the field is interrupted and a line appears.

But available methods cannot show the depth and size of cracks. New ultrasonic techniques are being developed to get this information.

Strong lighting has become a key requirement in underwater work. Dr. Robert Ballard of Woods Hole Oceanographic Institution, who is a writer for the National Geographic magazine, told the conference how essential it is in underwater exploration to have cameras that can photograph large areas, such as spaceship cameras do. This is the current effort, he said. Now, instead of looking at a tenth of an acre of ocean bottom, he said, photographic systems with extended lighting are shortly going into effect which will cover as much as seven acres in one shot with fine detail, working from remote-controlled submersibles.

Dr. Collier says that if scientists and engineers can combine Artoo-Detoos with manipulators that can pick up objects, push and pull things, turn valves, clean structures, and conduct inspections, their usefulness in supplanting divers in unfriendly environments and deeper waters is obvious. ''That's the future!'' he exclaims.

It is conceivable that someday these free-swimming submersibles may even come in handy in the frigid waters off eastern Canada where scientists are grappling with an entirely new combination: offshore oil drilling and icebergs. In all the world, only off eastern Canada is the incompatible odd couple of oil drilling and icebergs now keeping company.

That explains why Canadian engineers at Memorial University of Newfoundland in St. John's are pioneering what they call ''cold water engineering.'' They are learning to estimate the drift and draft of icebergs and are studying how the biggies, like floating skyscrapers weighing 200,000 tons or more, gouge the seabed as they bob into shallow water.

Dr. Ross Peters was one of several Memorial University faculty members addressing Oceans '81. He explained that icebergs form when Greenland Ice Cap glaciers break off into the water. The West Greenland Current carries them northward. They cross the Baffin Sea. The Labrador Current then carries them southward past Newfoundland, where they begin to disintegrate. Icebergs have been a shipping menace in this region for all time. As a matter of fact, it was about 300 miles southeast of Newfoundland that the Titanic went down.

In the exploration stage, drilling operators have to be able to move their rigs quickly. Hence the value of learning how to predict the direction and rate of drift of some mountainous table of ice that shows up on the horizon. Will it float safely by, or enter the rig's danger zone?

If an iceberg is small enough, it's easier to cope with the hazard by just lassoing it and towing it to a safe distance. The tugboat that services the rig drops a parachute overboard attached to the end of a heavy rope. Then the tug steams gingerly around the iceberg, picks up the chute, and pulls.

This is done with great caution, because icebergs are capricious. ''They are always moving,'' Dr. Peters says. ''They roll, turn, loop around, reverse direction, pieces fall off. A couple of times we've seen them turn completely over. They are very unstable beasts!''

Studies have revealed what a serious threat iceberg scouring poses for oil pipelines laid on the ocean floor. The result may be that when these fields off Newfoundland begin to produce oil in the next few years, ships, rather than pipes, may be used to transport the oil to land.