Exosuit: A “Personal Submersible” for Scientists

One physiological limitation that has always plagued divers is the one related to decompression obligations: the longer you are diving and the deeper you descend, the more inert gas will be absorbed, requiring longer and longer compression stops. To overcome this problem, commercial diving has developed the so-called “saturation” diving system. A characteristic of inert gas absorption is that after a certain period (about 12 hours), the human body becomes saturated with this gas and no longer absorbs it. As a result, decompression obligations will not increase further. In practice, divers are kept at a pressure equivalent to that they will encounter while diving by living in hyperbaric environments for several days and using a hyperbaric bell as a sort of “elevator” to descend and ascend from the operating depth without pressure variation. Although this procedure has been used for many years with excellent results, it requires very complex logistics regarding material, personnel, and training for divers. In addition, living at such high pressure, often equivalent to a depth of over 300 meters, produces a series of adverse effects on the human body both in the short and long term.

An alternative is to use mini-submarines capable of maintaining a normobaric internal pressure (i.e., equivalent to that encountered at the surface). Costs, logistics, and training are very high in this case.

A third solution is to use a rigid normobaric diving suit that combines the advantages of a mini-submarine with those of a diver. Some models of these systems have been used for several years, but their limitations have always been reduced maneuverability, strong dependence on surface support, and complex training for the operator.  Recently, the Canadian company Nuytco Research has developed a new model of rigid diving suit called “Exosuit” with favorable operability and safety characteristics.

The Exosuit is made of aluminum alloy, weighs about 240 kilos, and can operate up to 300 meters deep. The system is connected to the surface through an umbilical that provides power supply and audio and video communication. One of the key innovations is using an 18-joint system that guarantees a level of freedom of movement never experienced before in this type of diving suit. Despite its weight, the Exosuit is practically neutral once in the water. A system of four 1.6 horsepower electric thrusters housed in a sort of “backpack” allows the operator to move in three dimensions with minimal effort. The engines are controlled by two pedals placed under the feet of the pilot, who sits on a sort of motorcycle pillion. A rebreather electronically maintains the internal atmosphere, eliminating the CO2 produced, and guarantees up to 50 hours of survival, even if losing contact with the surface. A further advantage is that the Exosuit can be controlled from the surface, like an ROV, with an increase in safety and allowing personnel to use the system a relatively short training. A range of accessories, including LED lights, HD cameras, and sonar, complete the on-board equipment.

The Exosuit’s target is mainly scientific, and in fact, its first operational test was to take plankton samples in a canyon off the east coast of the United States at a depth of about 300 meters. This type of deep planktonic organisms are very important; for example, studies on the proteins of a jellyfish “Aequorea Victoria” have made it possible to discover essential mechanisms related to the development of neuronal cells of the brain, allowing Osamu Shimomura, Martin Chalfie and Roger Tsien to win the Nobel Prize for Chemistry in 2008. We’ll see if using the Exosuit will lead to other discoveries of a similar level.

Another research in which the Exosuit was used took place in the Aegean Sea in 2014 on the wreck of Antichytera, where a mysterious “mechanism” was found. It is supposed to be a “clock” most likely intended for astronomical calculations. The Exosuit allowed archaeologists to return to the wreck’s remains to make new observations and measurements.

The main advantage of the Exosuit is that a researcher can be trained in its use in a relatively short time, vastly less than what would be required to prepare a submarine pilot to become a scientist. In this way, archaeologists, biologists, and geologists will be able to dive in person to study the object of their research without having to delegate to remote systems or surface sampling.

During the preparation phase of the 2014 archaeological expedition to the Antichythera wreck coordinated by the Woods Hole Oceanographic Institution, I was lucky enough to be present and participate as a “visiting scientific diver” in part of the training. The maneuverability of the Exosuit in the water is considerable, and the logistics, although challenging, are much more simplified than those that would be necessary to use saturation divers or mini submersibles. The thing that impressed me the most, however, was how quickly it was possible to train researchers in the essential functions of the Exosuit so that they could use it safely. With the Exosuit and the systems that will certainly follow it, new horizons are opening up for underwater scientific research with enormous potential in scientific and technological progress.