Recovering an AUV after a mission can actually be riskier than launching one, but the operation itself is relatively simple. When the AUV team receives confirmation that the vehicle has reached the surface, the ship pulls up alongside the AUV, where a command is sent to release a float from the AUV’s nose. This float drifts away from the vehicle extending a recovery line from the float back to the vehicle. An air-powered cannon is then used to fire a grappling hook across the recovery line and the deck team uses those lines to attach the vehicle to the LARS. The LARS winches the AUV out of the water and into the LARS docking head. The LARS A-frame lowers the AUV back into its cradle on the back deck, where it’s locked down and washed with fresh water. It’s then rolled onto the removable rails back into it’s van, where the team will download the new data, change the batteries, and get it ready for the next mission.

With each new AUV mission completed, the sonar analysts sit down with the new data and look for potential targets. They look for anomalies on the seafloor with the right size and shape, as well as material properties, to match that of Earhart’s Electra. We found just such a contact in Mary Ann’s first survey box and decided to send her back down to re-image the target. Twenty-four hours later, the team gathered in the analysis lab to see the results. The re-imaging of a promising target involves using higher frequency sonar, which gives us a higher resolution image, and taking thousands of high-resolution still photographs. This particular target turned out to be geology – not an uncommon result. Regardless of a negative find this time, with each new re-imaging survey, we became more confident that our analysis of contacts was accurate, and we knew that when the time came for the next promising target, we’d be ready.

Once the team dialed in the trawl net operations, we had a series of successful tows that kept the science crew very busy. The opportunity to collect mid-water samples in this remote location for such an extended period of time was an unprecedented one and was truly a rare opportunity for our researchers onboard. Everyone on the team was excited to welcome the strange creatures aboard and were excited to see what the next net trawl might bring up to the surface.

Following the Waitt Institute’s helicopter flight towards Howland Island, the expedition leader, Ted Waitt, brought back with him a new perspective on Earhart’s last hours of flight, and, as a result, the team wanted to add more boxes to the search grid to reflect this new point-of-view. The experience of being in the air, so close to the island, and having difficulty picking it out against the shadows on the water, brought questions into play about how close Earhart may have needed to get to Howland, before being able to positively identify it. With this new insight in hand, the operations team discussed options for adding a small search area between Howland and Baker Islands, and finally decided on two new boxes to add to the search.

Part of what made CATALYST 2 a ground-breaking survey was our ability to run two 6000-meter Autonomous Underwater Vehicles, or AUVs, simultaneously. The custom launch and recovery configuration on the back deck of the Seward Johnson allowed us to survey the seafloor 24 hours a day, 7 days a week. With our techniques and turnarounds dialed in, the CATALYST AUV team was able to leap-frog Mary Ann and Ginger across 2000 square miles of underwater terrain. We were definitely testing the limits of this gear, and they proved out to be one of the best survey tools in use today.

About a week into the survey, we suffered a severe setback. During a night recovery, Ginger slipped under the ship’s stern and the ship’s screw made contact with the AUV’s tail section. After taking a good look at the damage, the AUV team determined the thruster housing was beyond repair and that a new one would need to be acquired. It would set us back several days, if not weeks. While we worked through solutions, the team leads went over recovery scenarios in order to prevent having the same type of incident in the future. We only had one AUV left, and we had to keep her moving through the search boxes as best we could.

University of Queensland biologist, Adrian Quinn, discusses one of the trawl net’s amazing catches – a live Anglerfish. This video includes rare footage of the Anglerfish, which the CAT 2 science team managed to keep alive for several hours after bringing her up to the surface.

After nearly losing one of our vehicles to the ship’s propeller, the CATALYST 2 team re-defined AUV recovery protocols to make the entire process safer. Even then, we were sometimes forced to deploy our secret weapon – Joe Lepore.

Even though the AUVs have a titanium frame and can withstand the pressure of 6000 meters of seawater, they are not invincible. While going through images that Mary Ann took during a camera test dive, we discovered just how close she came to not only hitting the bottom, but also potentially lodging herself in the rugged terrain. It’s a difficult task to fly a 2000-pound vehicle just 60 meters above the seafloor, especially when the seafloor isn’t flat. To counter some of the inherent problems, the AUVs have a built-in collision avoidance system. A pencil-beam sonar pings out in front of the vehicle and lets it know if needs to adjust its altitude to fly over approaching obstacles. In some cases, though, the vehicle can only move out of the way so fast. Thankfully, on this expedition, we managed to walk away with only a few minor scrapes.

Sometimes with a little bit of luck, a little expertise, and a whole lot of elbow grease, what could be a major setback is reduced to a small blip in the schedule. Following a mission abort by Mary Ann, the team discovered a failure of the motor in her tail thruster. They took the thruster to the AUV lab and tore it down, did varied diagnostic tests, and, in the end, declared it unfixable. With Ginger already sitting on the sidelines waiting for her own tail assembly fix, Mary Ann was the expedition’s only operating search vehicle, and she needed to get back in the water. Harbor Branch project manager and engineer, Lee Frey, refused give up. After endless hours of testing and troubleshooting, Lee had the motor working again. What we thought was going to be our second major disaster was narrowly averted.