The oceans make up around 70% of planet Earth, yet over 80% of the world's ocean remains unexplored. Since the global boom of ocean exploration technology began in the 1960s, deep-sea exploration has faced a number of barriers. Today, with fewer barriers in place than ever before, international efforts are underway to continue the exploration of the deep ocean.
Barriers to Ocean Exploration
Exploring the ocean is both expensive and technologically challenging—for reasons that are not so surprising. Robots created for deep-sea ocean exploration must be able to withstand the high pressure that comes with depth, operate without the need for maintenance for thousands of hours at a time, and be able to resist the corrosive effects of seawater.
Extreme Pressure
On average, the ocean is about 12,100 feet deep. At this depth, the pressure inflicted by the weight of the seawater above is over 300-times greater than the pressure we experience at the ocean's surface. At the deepest part of the ocean, about 36,000 feet below the surface, the pressure is over 1,000-times greater than the pressure at the ocean's surface.
Devices used for underwater exploration must be designed to withstand the intense pressure of the deep ocean. Submersibles designed to carry people aboard must also have the capacity to maintain an internal pressure compatible with what the human body can withstand. Typically, these manned submersibles use pressure hulls to control internal pressure.
However, these hulls can account for nearly a third of the total weight of the submersible, limiting the machine's capabilities. Until recently, the intense pressure in the deep ocean has been one hurdle preventing people from exploring the abyss directly.
Long Dives
It can take many hours for a submersible to get down to a target depth, let alone explore the environment. Given the substantial amount of time a submersible must remain underwater, all underwater robots must be built to be self-sufficient in a variety of circumstances.
There are three main types of robots used to explore the deep ocean: human-operated vehicles (HOVs), remotely-operated vehicles (ROVs), and autonomous underwater vehicles (AUVs). HOVs are submersibles designed to have people on board, whereas ROVs are operated by people remotely, typically from a ship at the surface. AUVs, on the other hand, are designed to be completely autonomous, exploring the ocean through pre-programmed missions. Once each mission is completed, the AUV returns to the surface for retrieval, at which point scientists get to process the data the AUV collected during its journey.