A "remotely operated vehicle" (ROV) usually is defined as a tethered, unmanned submersible. That is not entirely correct. Man is still in the loop, but on board a surface support vessel rather than in the vehicle. Here the "pilot" flies the vehicle using sensor inputs and TV imagery from the submersible.
U.S. Navy research and development produced the first practical ROVs in the early 1960s. By the middle of that decade the first Navy operational ROV was put into service. This was CURV, "Cable-controlled Underwater Recovery Vehicle," developed to help recover experimental underwater ordnance from offshore test ranges. CURV became famous when it helped recover a lost hydrogen bomb off Palomares, Spain, in 1966 and saved three men trapped in a submersible off Ireland seven years later.
In addition to large vehicles such as CURV and the prototype Mine Neutralization Vehicle (MNV), the Navy also produced several small swimming television cameras such as SCAT, SNOOPY, and EL-SNOOPY. Concurrently, vehicle accessories such as manipulators (i.e., mechanical arms), cameras, sampling devices, and work tools were developed to give these submersibles useful work capabilities. This research-and-development work supported Navy operational requirements such as mine countermeasures, seafloor objects evaluation and recovery, and general underwater inspection work.
These new submersible platforms were not adopted immediately by nonmilitary users. In fact, it would be more than 15 years later before they would be used extensively for commercial work. Divers and manned submersibles were the work platforms of choice in the 1960s and 1970s.
Now, all that has changed. The Navy stopped most ROV research and development nearly 20 years ago. Its legacy is a global industry that has now produced thousands of these submersibles. For example, one U.S. company—Deep Ocean Engineering—has built nearly 400 systems for operators in 30 nations and 11 navies. Today the Navy meets its operational ROV needs by procuring the submersibles from companies such as this.
Offshore oil and gas operations are the largest ROV workplace in terms of capital investment in equipment. Here giant ROV systems (vehicle, handling system, and control van) can cost upwards of $2 million. These are vehicles that can do all the tasks formerly done by divers or manned submersibles. The trend toward deeper ocean exploration and production mandates that ROVs must be used. Many offshore sites are simply too deep for divers. For example, in the Gulf of Mexico there is production from nearly a mile deep, and Shell Oil has exploratory drilling leases at depths close to 10,000 feet. This is a whole new direction for offshore petroleum development-a direction made possible by sophisticated ROV work systems.
The world's most impressive ROV system is Japan's KAIKO ("trench"). Operated by the Japan Marine Science and Technology Center, the $50-million system was completed in 1994. That March a dive was attempted to 36,000 feet in the Challenger Deep, the deepest place in the world ocean. Only a few feet from the seafloor, a problem with the umbilical cable caused loss of the television picture. The mission was aborted. In March 1995 this "mega-ROV" successfully made this dive capturing man's first photo and TV images at that site.
Also, there are about a half-dozen deep-diving ROV systems worldwide that can work as deep as 20,000 feet. With this depth capability, they can reach 98% of the global seafloor.
At the other end of the scale are the low-cost ROVs, which first appeared in the mid-1980s. With prices ranging from $15,000 to more than $100,000, these submersibles are found throughout the world engaged in a variety of inspection and light work tasks in water depths down to 2,000 feet. Recently, deeper-diving versions of these low-cost vehicles have been developed. Affordable ROVs for up to 10,000-foot depths may be just around the corner.
Small-ROV usefulness is not limited to oceans. On land they have been used at civil works sites such as dams and reservoirs, and also to inspect the insides of aqueducts and pipelines as long as 6.5 miles. A "fleet" of about 60 work inside the containment vessels of nuclear reactors doing specialized inspection and maintenance tasks.
Perhaps the most unusual work site is in a mile deep mine in Canada. A special ROV will "swim" inside a large acrylic sphere. Filled with heavy water (H30) the sphere contains an array of detectors to measure passage of neutrino particles from space. The submersible will help tune the array by physically moving the individual detectors.
ROVs in space? NASA has used them to simulate on earth the anticipated control problems for remotely operated planetary lander vehicles. As part of this effort, they flew a specially built ROV under the ice in the Antarctic. The pilot controlling it was at NASA's laboratory in the San Francisco Bay Area. Now, a new ROV development program will be part of the agency's effort to explore a huge ice-covered ocean on Europa, one of Jupiter's moons. In order to replicate those operating conditions as accurately as possible, NASA will operate the new ROV through the thick ice covering Lake Vostok in the Antarctic.
In its many forms and shapes, the ubiquitous remotely operated vehicle has become, and will continue to be, the standard underwater work platform.