The deep sea is a mysterious place. A place that science knows very little about. Modern engineering is here to change that, with a new wave of sophisticated technology that is allowing us to learn more about the deep sea than ever before. From the stars to the seas… You know what they say. We know more about space than we do about our oceans. Okay, in reality that may not be the case. (For instance, we don’t even know how big space is.) But the fact remains that we are staggeringly naive about what’s going on beneath the surface of the big blue. So mysterious and unchartered is the deep sea that you really don’t need to leave our planet to venture into an alien landscape. There are some seriously strange creatures down there. Creatures with which we share a common origin. There are underwater volcanoes spurting materials from the centre of the Earth into the sea. Materials that some scientists believe may be the building blocks of life. The seas cover 71% of the Earth’s surface. Yet – depending on where you go for your facts – between 95% and 99.5% of the sea remains unexplored by human life. It’s why some scientists speculate that we have only discovered a measly one-third of oceanic species. Diving in to mysterious seas through engineering Deep sea exploration is expensive, it’s difficult and it’s dangerous. It’s dark, it’s often murky and the deeper you go, the more hostile and crushing the ambient pressure becomes. (At 500 metres down, the ambient pressure is fifty times higher than the atmospheric pressure at surface-level. Dive beyond 40 metres and decompression stops are necessary on the way back to the surface.) Yet necessity is the mother of invention. And when the world poses a problem, engineers have a remarkable knack of finding answers. In recent decades technology has allowed scientists to begin to explore the deepest depths of the ocean. The most storied submersible of all time? In 1964 the world’s first deep-sea submersible capable of carrying passengers was launched. It was called Alvin and – at the time – could only dive as deep as around 30-50 feet. Since then Alvin has completed over 4,600 dives, taken over 13,000 scientists, engineers and observers to the seafloor and – thanks to a number of upgrades over the years – can plunge to a depth of more than 14,500 feet. Alvin’s career has been remarkable. In 1977 researchers aboard the vessel discovered the first hydrothermal vents in the Pacific Ocean. To date Alvin has found a further 24 hydrothermal sites across the Atlantic and Pacific Oceans. In July 1986 Alvin made twelve dives to the Titanic to photograph the wreck and in 1966 Alvin helped to locate and retrieve a lost hydrogen bomb. The vessel has also enabled scientists to discover around 300 new underwater species, including bacteria, foot-long clams and ten-foot long tube worms. But what of the sub’s physical characteristics? Well, Alvin weighs in at 35,200 lbs and measures 23 feet long, 12 feet high and 8 feet wide. It’s propelled by five hydraulic thrusters and features an electrical system powered by lead-acid batteries. So far, so simple. But Alvin really is a special box of tricks. On the outside of the sub you will find film and video cameras that capture images of the deep sea environment beyond Alvin’s titanium walls. There are also two hydraulic arms on the front of the vessel, which can extend up to 75 inches and lift up to 200 lbs each, for collecting live biological and geological samples. Wand-shaped electrode sensors capture chemical readings of the environment while incandescent, sodium-scandium and thallium iodide external viewing lights allow the pilot and observers to see into the pitch-black ocean environment. Alvin also includes a computer/data display/recording system, an altimeter, a gyrocompass, a navigation and tracking system, sonar, an underwater telephone to call its host ship, temperature probes, heat flow probes, a CTD and a magnetometer. In short: Alvin is an engineering marvel – and it’s still in service. ROVs The world’s first submersibles – such as Alvin – transformed the discipline of deep sea exploration. Yet the fact remains that sending scientists into an environment that’s innately hostile to human life is dangerous. That’s where ROVs (remotely operated vehicles) come in. These vessels are controlled by a team on board a ship via tether cable and are capable of doing all the things regular submersibles can: collecting photography and film, gathering biological and geological samples and analysing water temperature. Examples of these ROVs include Ventana and Jason II/Medea. AUVs Maps of many parts of the ocean floor are not yet as detailed as some of the maps we have of other planets. Here to help fix that is another class of submersible. AUVs (autonomous underwater vehicles) are capable of navigating the deep sea and collecting scientific data without any human control. Vessels such as Sentry are creating detailed maps of the seafloor using sonar and taking photographs of fascinating geological features such as deep-sea vents and cold seeps. Sentry‘s navigation system uses a doppler velocity log and inertial navigation system, aided by acoustic navigation and communication systems (USBL or LBL). The USBL system also provides acoustic communications, which can be used to obtain the vehicle state and sensor status as well as to retask the vehicle while on the bottom. Undersea instrumentation ROVs and AUVs are capable of providing unparalleled insight into deep-sea activity. The problem is that it’s just a snapshot. For a better understanding of what’s happening in our seas, it’s necessary to utilise scientific instruments that can monitor a body of water continually. This instrumentation already exists. Scientists have at their disposal a suite of sensors that can perform a huge range of different tasks, including monitoring water temperature, measuring the speed of currents, gathering information on water acidity, imaging plankton and recording whale calls. A spacesuit for the deep ocean Give or take your specific location in the world, when you reach the seabed in the deep ocean you have the crushing weight of around fifty jumbo jets resting on you. That makes it impossible for oceanic explorers to get out there and, well, explore. Until now. A new advanced diving suit called ExoSuit could liberate deep-sea exploration from the confines of the submarine, making biological discovery and undersea construction easier than ever before. Essentially, we’re talking about a 530lb metal spacesuit, re-engineered for use underwater. It provides divers with a flexible, pressurised environment that simulates the atmospheric conditions at surface-level, complete with thrusters to propel in any direction. The suit also features a fibre-optic cable that’s tethered to a nearby vessel, allowing the diver to communicate and share data with colleagues through built-in cameras and a microphone. One soggy step for man, one giant leap for mankind? Watch this space. Exploring an unfathomable expanse We know that the sea is vast. But rarely do we stop to think how deep it is. Or what’s going on deep beneath the surface. Engineering innovation is making it possible to peer into uncharted territories, make new scientific discoveries and learn more about the very origins of life on Earth.