JUDY WOODRUFF: Now the search for that missing Malaysian airliner. It underwent a major shift today, as officials decided to give up listening for pings and start looking at the ocean floor.For days, crews on the Australian Navy vessel Ocean Shield had been preparing a U.S. Navy robot submersible to go deep in the Indian Ocean. Their chance came today, six days after the last known signal from what may be the plane’s recorders.
ANGUS HOUSTON, Air Chief Marshal, Search Coordinator: Today is day 38 of the search. The guaranteed shelf life of the batteries on the aircraft black boxes is 30 days.
JUDY WOODRUFF: Angus Houston is running the search off his country’s western coast.
ANGUS HOUSTON: Despite the lack of further detections, the four signals previously acquired taken together constitute the most promising lead we have in the search for MH370. We need to pursue this lead as far as possible.
JUDY WOODRUFF: As this animation shows, the submersible, Bluefin-21, can create a 3-D sonar map of any debris on the ocean floor, but it’s slow-going. Each mission can take up to 24 hours. And this first trip will cover only about 15 square miles in a search area that spans some 18,000 square miles.
ANGUS HOUSTON: I would caution you against raising hopes that the deployment of the autonomous underwater vehicle will result in the detection of the aircraft wreckage. It may not. However, this is the best lead we have, and it must be pursued vigorously.
JUDY WOODRUFF: Meanwhile, an aerial search continues, although officials say the chance of spotting any debris is increasingly unlikely. Investigators are also analyzing a sample from an oil slick, but that process will take several days.
Now that the search has shifted, there are new questions people have about the submersible vehicle and its role.
David Kelly is the CEO of Bluefin Robotics, which makes the Bluefin-21
David Kelly, welcome to the NewsHour.
Give us a sense of the task that this robotic device is being asked to perform.
DAVID KELLY, CEO, Bluefin Robotics: Well, Judy, the vehicle is rated to 4,500 meters in depth, which is two-and-a-half miles down, which is about the depth of the ocean in this area.
And it will go on a series of dives to survey the ocean bottom and come back with imagery that can then be analyzed to see if there’s any objects of interest.
JUDY WOODRUFF: How does it go about doing its job? I mean, we showed some of the visual animation there. But once it gets to the bottom or close to the bottom, how does it operate?
DAVID KELLY: Well, the vehicle is what is called autonomous. There is no operator in the loop. So it is programmed on the surface for the area to be surveyed. The vehicle will descend down the two-and-a-half miles. It has navigation instruments on board, so it knows where it is.
As it approaches the bottom, it will stop about 50 meters above the bottom, which is a good surveying height, and it will turn on the sonars and it will image the area. And the sonars can image about a half-a-mile across. And it will run parallel lines, just like you are mowing your lawn, and it will go back and forth overlapping. And then that data will be collected on the vehicle.
And when it returns to the surface, the data is off-loaded, the batteries on the vehicle are changed, another mission is programmed. The vehicle is relaunched, and, meanwhile, the data that has been recorded from the prior mission is processed and analyzed looking for objects.
JUDY WOODRUFF: And, again, these are sonar images that it’s bringing back.
DAVID KELLY: That’s correct. At that depth, it’s pitch-black. It’s slightly above freezing. There’s tremendous pressure, and the best sensor to scan a large area is a sonar. So these are images that are painted with sound, so the objects look slightly different than if you were looking at it with a camera.
But the analysts can still see whether an object is manmade or part of the natural surroundings. And that is the key point that they would be looking for.
JUDY WOODRUFF: You mean by the shape of it?
DAVID KELLY: Correct. Most of the objects in nature are going to be rounded. You can tell the bottom, and most manmade objects will have some sharp edges or right angles, and those will show up on the sonar imagery.
JUDY WOODRUFF: How durable is this submersible? What do you worry about it running into — problems it could run into down there?
DAVID KELLY: It’s a very harsh environment. And pressure is the biggest issue.
At that depth, the pressure is about three-and-a-half tons per square inch. That would be the equivalent to having a Cadillac Escalade balanced on your thumbnail. So there is tremendous pressure on the vehicle and the equipment. It is a tough environment to operate in.
JUDY WOODRUFF: We have also read, David Kelly, that there is some silt in this area, very fine sand or something like that. What is known about that and how much of an issue is that?
DAVID KELLY: We have run our vehicles around the globe in almost all the oceans across many bottom types. Silt is one type of bottom.
There’s mud, there’s sand, there’s rocks. You will get different sonar returns from the different bottom types. You can adjust the equipment to deal with that. So, again, it’s environments we have seen before.
JUDY WOODRUFF: So, if something is under the silt or has sunk into the silt, it could still image it; is that what you’re saying?
DAVID KELLY: Well, the sonars that are used would image on the surface of the silt. So if an object was down below the silt, it wouldn’t necessarily be imaged.
JUDY WOODRUFF: What happens next? I mean, if it comes back with an image that is interesting, that people, that the experts think could be something, what do you — what happens then?
DAVID KELLY: Well, I think probably, most likely, the next step would be, go get a camera image of it.
Now, this — the Bluefin-21 that is deployed does have a camera payload. It’s a high-definition still camera. Typically, when we image an area on the ocean bottom, we would reduce the size of the area to about 100 meters square, a hundred yards square. They also could send down an ROV, a remotely operated vehicle, with a camera.
But most likely, they would want to get a camera image of an object to compare that with the sonar image to understand what they have.
JUDY WOODRUFF: But do I understand you to say they could be taking a picture, a photo at the same time it is down there doing the sound images?
DAVID KELLY: No, those are two separate payloads. They’re swappable, they’re easily changed in the field on the ship. But only one of the payloads can operate at a time.
And it has to do with the difference in height that the vehicle runs at. So when are you collecting sonar imagery, it would be higher off the bottom at about 150 feet. When are you taking a camera image, light doesn’t go very far at that depth and in that darkness, so you need to be much closer to the bottom, about 15 feet.
JUDY WOODRUFF: Based on what you know, how realistic do you believe the odds are that they’re going to be — you’re going to be able to find what’s left of this aircraft?
DAVID KELLY: Well, this is a tough challenge, and we salute the men and women that have been working for a month to resolve this mystery.
They have — over time have worked to reduce the search area. They’re now focusing the vehicle on those areas that they think have the most promise. But I think, in reality, this is a — it’s a tough problem. It’s going to require persistence and tenacity, and I think people need to understand it’s going to take — could take weeks, could take months.
It may be tedious on the outside, but you have to follow a regimented, well-planned search and just dogmatically execute it.
JUDY WOODRUFF: Well, David Kelly with Bluefin Robotics, we thank you for helping us understand what is going on.
DAVID KELLY: Thank you.