Barely a month after the undersea robot ABE imploded and was lost in the depths, ABE's "son," Sentry, suffered fire and flooding that destroyed critical internal components. But a team of engineers rallied to rebuild its electronics at sea and put the vehicle back in the water in four days.
Sentry was deployed from the research vessel Atlantis near the Galápagos Islands on April 4 and was descending for a routine night of seafloor mapping when engineers noticed it was heading straight to the bottom instead of starting its mission. Minutes later, at about 1,700 meters, the vehicle's emergency controllers kicked in, releasing drop weights to allow Sentry to rise to the surface for an early recovery.
"When it came to the surface, it was stone-cold dead," said Dana Yoerger, a scientist at Woods Hole Oceanographic Institution (WHOI), who helped design Sentry. "We knew there could be a big problem."
WHOI engineers found seawater in Sentry's main housing. Rod Catanach, the Sentry team's mechanical engineer, carefully inspected the vehicle and diagnosed the cause: A pinhole fracture in a cable connector allowed seawater into the housing. It not only flooded the equipment, it also sparked a fire amid the electronics. Catanach assessed the damage. He thought Sentry could be fixed and began to disassemble the robot.
Read the complete article in WHOI's magazine Oceanus here.