The oceans make up more than 72% of the surface area of our planet, yet we have only a 4% understanding of what lies beneath them. That’s correct – we are more knowledgeable about the surface of Mars than our own oceans. But in the last hundred years, brilliant people and daring explorers have invented amazing technologies that are finally tearing back the curtain on Earth’s final great frontier. From submarines that resist the crushing pressure to robots that map the seafloor, these innovations upended everything we thought we knew about our blue planet.
Let’s learn more about the technologies that have revolutionized ocean exploration and are still uncovering secrets hidden in the depths.
THE BEGINNINGS: CRACKING THROUGH THE TOP SOIL
Back before all of the fancy gadgets and technology equipment we have today, there was exploring the ocean by holding your breath and seeing where you end up. Pearl divers days of yore were able to dive down to about 30 meters, but that was the extent of human capacity without aid. Then along came some inventors who began thinking about how to outsmart the deep in a different way.
Diving Bells: The First Move Down
The diving bell was among humankind’s earliest, earnest attempts at underwater exploration. Imagine that a big, inverted cup is descending toward the water. The trapped air formed a pocket in which divers could breathe when beneath the waves. That design was improved in 1690 by Edmund Halley (yes, the comet guy) with weighted barrels of air that could refresh the oxygen supply.
These bells were not perfect: they were cramped, dangerous and couldn’t descend very far. But they demonstrated something crucial: Humans could spend long periods underwater with the right technology.
SCUBA: Freedom to Explore
The invention of the self-contained underwater breathing apparatus (SCUBA) in 1943 by Jacques Cousteau and Émile Gagnan changed the way we explore our oceans. Suddenly, divers were not connected to the surface. They could swim unencumbered, discovering coral reefs, caverns and sunken ships with new freedom.
SCUBA gear democratized the ocean for scientists, filmmakers and recreational divers. It enabled marine life to be studied in its natural environment rather than only after specimens had been brought to the surface.
Submersibles: Going Where Humans Cannot
While SCUBA opened up the shallow seas for us, the deep ocean is still out of reach. The pressure at those depths would instantaneously crush a human body. Enter submersibles: bespoke vehicles engineered to shield explorers from the ocean’s deadly clasp.
Bathysphere to Bathyscaphe: Forming of a New Depths
In 1930, William Beebe and Otis Barton plunged 435 meters in a steel sphere they dubbed the bathysphere. It was essentially a metal ball with windows, lowered on a cable. Terrifying? Absolutely. Revolutionary? Without question.
Next came the bathyscaphe – an improved version that could act independently instead of dangling from a vessel. That feat came in 1960 when Jacques Piccard and Don Walsh piloted the bathyscaphe Trieste to the deepest point on Earth — the Challenger Deep of the Mariana Trench, nearly 11,000 meters below. They stayed for 20 minutes at the bottom of the world, demonstrating that humans could visit even this last and most extreme of destinations.
Modern Deep-Sea Submersibles
Today’s submersibles are technological marvels. Vehicles like Alvin (operated by the Woods Hole Oceanographic Institution) have made thousands of dives since 1964. Alvin has discovered hydrothermal vents, dived down to the Titanic wreck, and assisted scientists in unraveling deep sea ecosystems.
These modern subs feature:
- Crush-resistant titanium hulls
- Robotic arms for collecting samples
- High-definition cameras for documentation
- Advanced life support systems for long-duration missions
- Sophisticated navigation equipment
Key Submersible Milestones
| Year | Vehicle | Milestone | Depth Reached |
|---|---|---|---|
| 1960 | Trieste | First visit to Challenger Deep | 10,916 meters |
| 1964 | Alvin | Began long research career | 4,500 meters |
| 2012 | Deepsea Challenger | James Cameron’s solo dive | 10,908 meters |
| 2019 | DSV Limiting Factor | Multiple dives to deepest points | 10,925 meters |
ROVs: No Risk With the Eyes and Hands
Remotely Operated Vehicles (ROVs) upped the ante by eliminating human exposure to danger altogether. These robot explorers can dive deeper, linger longer and take risks that would be unacceptable with human crews on board.
How ROVs Work
ROVs are attached to the ship by a cable that supplies power and controls. On the surface, a pair of operators work in shifts to manipulate the vehicle with joysticks and monitors, effectively playing an extremely costly video game whose implications reverberate all over the world. Some ROVs can be small enough to fit in a backpack, others are the size of a car.
The tether contains:
- Power wire to run motors and equipment
- High definition video fiber optic cables
- Communication lines for control signals
- Additional cables for special sensors
What ROVs Have Discovered
ROVs have played a critical role in some of the most significant discoveries in the ocean. They’ve explored underwater volcanoes, discovered never-before-seen species, scoured for shipwrecks and even pitched in on the response to the Deepwater Horizon oil spill.
For example, the ROV Jason has completed more than 1,000 dives and contributed to the discovery of many new species. ROVs can operate in environments that would immediately kill humans – around volcanic vents with temperatures over 400°C, or in toxic, methane and sulfur filled places.
AUVs: The Independent Explorers
Autonomous Underwater Vehicles (AUVs) take independence literally. These robots, unlike ROVs, are not attached to anything. They are encoded with their mission, put into the ocean, and carry out their duties on their own before coming home.
The Brain Behind the Machine
They rely on advanced artificial intelligence and navigation systems to navigate autonomously. They rely on:
- Inertial navigation systems (like very good compasses)
- Sonar to avoid obstacles
- Pre-programmed routes and objectives
- Sensors to collect data automatically
Mapping the Unknown
AUVs in particular are very good at mapping the seabed. They’re able to survey large swaths of ocean bottom far more quickly and inexpensively than ships or submersibles. The Woods Hole Oceanographic Institution operates the AUV Sentry, which can descend to 6,000 meters and map out 100 square kilometers in a single mission.
These vehicles have found undersea mountains, charted hydrothermal vent fields and mapped the complex topography of the ocean floor. They are crucial to producing high-resolution maps that help us make sense of ocean currents, find mineral deposits and locate important habitats.
Sonar: Seeing With Sound
There’s not much light under the water — you understandably can only see about 60 meters in crystal-clear water. But sound travels exceptionally well through water, which is why sonar (Sound Navigation and Ranging) has become our chief way of “seeing” under the sea.
How Sonar Changed Everything
The way sonar works is it sends out sound waves and listens for echoes. How long it takes for the sound to echo back tells you how far away whatever it hit is. Together, millions of such measurements can be used to build detailed three-dimensional maps of the ocean floor.
There are two main types:
- Single-beam sonar – Produces a basic image of the sea floor directly under a ship
- Multibeam sonar – Uses multiple beams to map vast areas of the seafloor
Revealing Hidden Worlds
Multibeam sonar has shown us features we had no idea were there. We’ve found thousands of submarine mountains, or seamounts, and deep trenches that could swallow Everest whole and complex underwater landscapes to rival anything on dry land.
The technology has also been used to find shipwrecks and ancient settlements below the waves, in addition to signs of meteor impacts on the ocean floor.
Satellite Technology: The View From Above
Satellites might not seem like they can help in delving into the ocean – after all, they’re up in space. But for modern oceanographers, satellites are indispensable instruments.
What Satellites Can See
Satellites can’t look through water, but they can take measurements:
- Ocean surface temperature
- Wave heights and patterns
- Ocean color (indicative of phytoplankton levels)
- Sea level changes
- Surface currents
- Slight bumps in the ocean surface that give away underwater mountains
Gravity and the Seafloor
You wanna hear something wild: Giant underwater mounds cause little bumps in the surface of the ocean when they tug at it with their gravity. Satellites can detect these bumps (which may be just centimeters high) and use them to map the seafloor without ever laying eyes on it.
It is a method that has led to the creation of global maps of the ocean floor, displaying sea features that were completely unknown.
Underwater Drones and Gliders
The latest generation of ocean research instruments includes underwater gliders — vehicles that “glide” through the water with changes in buoyancy instead of propellers.
Gliders: Marathon Swimmers of the Ocean
Underwater gliders are incredibly efficient. They use their wing-like fins to turn the vertical into horizontal so they can rise and fall through the water in currents. This makes it possible for them to travel thousands of kilometers over months, while recording data all the way.
Gliders measure:
- Temperature and salinity profile at various depths
- Ocean currents
- Biological indicators
- Chemical compositions
Comparison of Ocean Exploration Vehicles
| Technology | Depth | Duration | Best Use | People |
|---|---|---|---|---|
| SCUBA | 40m | Hours | Shallow reef studies | Yes |
| Submersibles | 11,000m | Hours | Deep exploration | Yes |
| ROVs | 11,000m | Days | Detailed work | No (Remotely controlled) |
| AUVs | 6,000m | Months | Wide-area surveys | No |
| Gliders | 1,000m | Months | Long-term monitoring | No |
Sensors and Sampling: It’s All in the Detective Work
If you think about “the clarity of ocean” it’s not just looking, but measuring and analyzing and understanding. We can now study the ocean in ways that were not possible just a few decades ago, thanks to modern sensor technology.
Chemical Sensors
These devices can detect:
- Dissolved oxygen levels
- pH (ocean acidity)
- Nutrient concentrations
- Pollutants and contaminants
- Carbon dioxide levels
It is important to understand ocean chemistry in order to track climate change, monitor pollution and protect marine ecosystems.
Biological Sensors
The development of eDNA technology has transformed the way we approach the study of marine life. Animals shed their DNA into the water through skin cells, waste, and other biological materials. When scientists analyze water samples, they can discern which species are found there without ever laying eyes on any of them.
This technology has not only found new species and followed rare animals but also helped to map where life thrives in diverse ocean regions.
Communication Systems: Staying Connected
Communication is among the most difficult issues in ocean exploration. Radio waves do not penetrate water, so engineers have come up with some creative workarounds.
Acoustic Communication
The same way whales communicate with sound over long distances, underwater vehicles transmit data using acoustic modems. It’s slower than WiFi (a lot slower!), but it works when nothing else does.
The Information Problem
The high-definition cameras on deep-sea vehicles can result in data coming off them like a firehose. But the narrow bandwidth of underwater communication makes it impossible to send most of this data in real-time. Instead, the vehicles are equipped with terabytes of data storage and deliver it after they resurface.
3D Reconstruction and Virtual Reality
Technology isn’t just enabling us to explore the ocean — it’s allowing us to share what we see.
Photogrammetry in the Deep
Photogrammetry is also used by scientists to create high-resolution 3D models of underwater sites. By snapping hundreds or thousands of overlapping photos, software can piece them together into reliable 3D reconstructions.
This technique has documented:
- Coral reefs with millimeter precision
- Archaeological sites
- Shipwrecks
- Hydrothermal vent systems
Bringing the Ocean to Everyone
Virtual reality allows people to “dive” to the ocean floor without getting wet. This means students can visit a coral reef in their classroom, researchers can investigate a site without costly expeditions and the public can immerse themselves in the wonders of the ocean.
The Future: What’s Coming Next
The technology in the expedition of our oceans is improving by leaps and bounds. Here’s what’s on the horizon:
Swarm Robotics
Rather than send one expensive robot, future missions could deploy dozens or hundreds of smaller robots that operate like a school of fish. Individually, each robot would be inexpensive and unremarkable, but together they might cover great distances and perform complicated activities.
Artificial Intelligence
AI is learning to automatically identify and classify marine life. In the future, it might be up to a new vehicle to recognize species, sense interesting activity and choose what it wants to investigate — all without any human help.
Energy Innovations
Battery life dictates how long vehicles can explore. New energy technologies — from advanced batteries to ocean thermal energy converters — would make missions possible for years rather than months.
Biotechnology
Researchers are examining how deep-sea creatures navigate life under extreme pressure and devising new materials inspired by their home in the sea. These bioengineered materials could lead to stronger, lighter vehicles that explore new depths.
Why Ocean Exploration Matters
You may ask yourself why we’re dedicating so much time exploring the ocean. The question concerns every living person on the planet.
Global seawater produces more than half of the oxygen we breathe. It maintains the climate by soaking up heat and carbon dioxide. It feeds billions of people. It includes assets that might help us to meet tomorrow’s mineral and energy needs.
But we cannot defend what we do not comprehend. Ocean exploration helps us:
- Track climate change effects
- Find new drugs (several are made by marine organisms)
- Find sustainable food sources
- Understand Earth’s geology and history
- Predict natural disasters like tsunamis
- Locate and protect endangered species
Learn more about the importance of ocean exploration and conservation from NOAA Ocean Exploration.
Challenges That Remain
Even with all our technological progress, ocean exploration is heavily burdened by:
Pressure: For every 10 meters you descend, another atmosphere of pressure exerts itself. At the ocean’s lowest points, pressure is more than 1,000 times higher than we experience on land.
Darkness: Beyond about 200 meters, there is no sunlight at all. Exploratory vehicles will have to carry their own light.
Cost: Operating ocean-going research vessels can cost between $30,000 and $50,000 each day. Submersibles and ROVs are expensive to make and maintain, costing millions of dollars.
Vastness: The ocean is enormous. Despite all our modern technology, the level of detail required to map it out would take centuries.
Hostile Environment: Saltwater corrodes equipment, cold temperatures affect batteries and unexpected currents can destroy or lose costly vehicles.
Wrapping Up the Journey
Technology for ocean exploration has advanced phenomenally since the days of the diving bell and brave breath-holders. The armamentarium of submersibles, robots, sensors and satellites available today provides capabilities that would have appeared as science fiction to the early pioneers in ocean exploration.
We have found life thriving at hydrothermal vents in spots we thought no life could exist. We have found underwater rivers, lakes and waterfalls. We have discovered thousands of new species, and we’ve learned that the ocean floor is every bit as varied and complex as any terrain on land.
But perhaps most crucially, these technologies have taught us how much we still don’t know. Every answer raises new questions. Every discovery reveals new mysteries.
The ocean remains a mysterious keeper of secrets about the history of our planet, clues to our future and probably things we haven’t even thought to ask about yet. And with the advancing tech who knows what we’ll find next?
The golden age of ocean exploration is upon us — and the surge in curiosity it inspires will eventually flood our politics as well.
Frequently Asked Questions
How far can modern submarines dive?
The majority of research submersibles can descend to depths between 4,000 and 6,000 meters—more than 99 percent of the ocean’s floor. The deepest trenches, deeper than 10,000 meters, can only be reached in specialized vehicles like DSV Limiting Factor. Naval submarines usually stay at the much shallower depths of 300-600 meters.
Why is space exploration easier than ocean exploration?
Even the ocean’s crushing pressure is more difficult to engineer for than the vacuum of space. Seawater also causes equipment to corrode, jams radio signals and makes communication almost impossible. And then, because the ocean is so immense and so dark, we do not know what’s there until we are right beside it, as opposed to space, where we have the ability to look at things that are very far away with telescopes.
How much of the ocean has been explored?
Scientists say we have detailed knowledge of less than 5 percent of the ocean and have mapped only about 20 percent of its seafloor using high-resolution sonar. More than 90% of the ocean is uncharted, making it Earth’s final frontier.
Underwater craft: How long can vehicles stay submerged?
It varies widely. SCUBA divers may stay underwater for hours. Occupation of manned submersibles is normally between 6 and 12 hours. As long as the support ship remains on station, ROVs can operate for days. AUVs and gliders can remain on-station for months; some gliders have missions of over a year’s duration.
What deep ocean finding has surprised the scientific community?
Hydrothermal vents were a big shock: whole ecosystems flourishing without sunlight, fueled by chemicals from the Earth’s interior. They also have seen fish living at deeper-than-expected depths, plastic pollution in the deepest trenches and signs of underwater lakes and rivers chugging along far below the seafloor with water so salty it might as well be syrup.
Is it possible for an average person to explore the ocean?
Yes! Most anybody who is taught properly can participate in recreational diving. Some companies provide tourist submersible trips at a few hundred meters. Thanks to virtual reality experiences, anyone with a VR headset can explore the deep seas. Citizen science projects also allow people to help make a difference by participating in ocean research from home.
What is the upcoming big development in ocean exploration to look forward to?
The next big jump, many experts believe, will be artificial intelligence and swarm robotics. Get ready to envision how hundreds of collaboratively connected robots can explore and map the ocean on their own, discovering things and sharing data in real time. It is believed by some, that bio-inspired engineering will also bring us vehicles which behave and move more like sea creatures.
