The bottom of the ocean is one of the least explored areas on earth - so what’s the best way to explore it? As well as sending people down, you can send autonomous submarines. Graihagh Jackson spoke to Professor Russ Wynn, Chief Scientist of marine robotics from the National Oceanography Centre.
Russ - There’s a lot of different uses of marine robots in the sea and some of them are either dull or dangerous or what we might call dirty. So there’s applications in the marine environment where we might want to send out a marine robot to do something for months at a time that would be really boring if you were down there doing it yourself.
There might be areas we want to access, such as under ice in polar regions, where we just physically can’t get to at the moment with manned vehicles.
There might also be areas where we would need to respond rapidly in a situation that could be both dirty and dangerous, like an oil spill, where the ability to send a robot out quickly or to send a 100 robots out quickly would give us an advantage. And, again, that’s something we couldn’t do with manned vehicles.
Graihagh - A lot of applications there. But also down there you have to deal with astonishing pressures - how do you engineer something to ensure that they just don’t get crushed under all that weight?
Russ - We run a fleet of yellow submarines at Southampton that are depth rated down to 6,000 metres. Actually, when you see the yellow submarine, and some of the listeners will be familiar with images of Boaty McBoatface and other yellow submarines…
Graihagh - I’m thinking of the Beatles. We all live in a yellow submarine…
Russ - Exactly. That’s really what they look like - they just don’t have people in. The actual outer shell is fibreglass and it’s free flooding, so that outer shell isn’t totally depth rated to those pressures. What we have inside, the important bits of the vehicle, like the computer, the batteries, the sensors, they’re all individually pressure rated and inside aluminium or titanium housings that mean that they can withstand pressure down at depths up to 6,000 metres.
Graihagh - When you say “flooding,” do you mean literally parts of the submarine flood whilst these other areas - these electronics - don’t flood?
Russ - That’s right, yeah. The outer hull, the water comes into that and so it’s neutrally buoyant effectively, and the inner important bits, the guts of the machine, are the ones that we really protect. It’s a bit like a human being. You’ve got your ribcage that protects your really important bits, but your skin is what’s holding all the water in.
Graihagh - It’s an interesting thought, isn’t it? I dread to think what would happen to our skin if we went down that deep! Now are these things entirely autonomous or are they something that you control from the surface?
Russ - At the moment we have two types. We have surface vehicles that we can communicate with via satellite - a little bit like mobile phone communication. So with those surface vehicles we can keep in contact with them all the time, get data back from them and talk to them and command them to do different things.
For the vehicles that go down into the depths. At the moment they have typically have an endurance of a few hours to a few days. And what we’ll do is we’ll give them a mission that will go into the computer of the vehicle. The vehicles will then go and complete its mission as best it can and then it will come back to the surface and it will be collected.
At the moment they’re relatively unintelligent and what we’re moving into now is an era where those vehicles will actually be able to adapt to the environment that they’re in. So, if they find something interesting on the seabed, they will be able to make a decision about how they then go and change their strategy to go and look at that in more detail.
Also, we’re looking at having the vehicle's processing a lot of the data they collect onboard and they can only then send snippets of those data back to us, maybe via a surface vehicle that acts like an acoustic communications gateway. That way it means they’re sending back the really important information so that the pilot back home can then make a decision about what to do next.
Graihagh - Can you give me a couple of examples - perhaps your favourite missions that are going on?
Russ - Boaty’s the yellow sub that many of the public will have heard of and it’s just come back from a great mission down in the southern ocean near Antarctica where it’s flying around in a current where cold water is being transported from the poles into the rest of the ocean. We’re trying to understand how variations in that current might reflect a wider signal of global warming and environmental change. So, by actually being able to fly Boaty within that current for periods of up to 3 days at water depths of several thousand metres, the scientists that were leading that project got new insights into that current and how it might be varying over time, and there’s no other way they could have collected those data.
We’ve also just come back from a mission in the north sea where, again, a boaty type submarine was looking at how we can use that technology to monitor our ability to store carbon dioxide in sub-sea storage reservoirs in areas like the north sea and lock up that carbon dioxide and, therefore, hopefully mitigate the carbon dioxide levels that we’re seeing in the atmosphere. Obviously, what you want to try and do is make sure that carbon dioxide doesn’t then start leaking into the ocean and then back up into the atmosphere. So we can use these yellow submarines to go out for weeks and months at a time doing very routine surveys of the seabed and making sure that carbon dioxide is locked up under the seabed where it should be.
Graihagh - I do like the fact that Sir David Attenborough’s boat the submarine on board was called Boaty McBoatface. What was the one from the North Sea carbon dioxide mapping one called - do you know?
Russ - The technical name is autosub long range. It’s a vehicle that our engineers developed at the National Oceanography Center. But, actually, that autosub long range family is now what we’re calling the Boaty family. There’s not just one Boaty submarine, there’s 3 and soon there’s going to be 6. So that family’s growing quite quickly and we’ve got all sorts of ambitious missions planned for that family of vehicles in the next few months and years.