May 19, 2021. After a spate of very good runs in the field, the Orpheus team pushed endurance capabilities on the vehicle on yesterday’s dive. To reach the surface, Orpheus carries ascent weights, which, when dropped, significantly increase its buoyancy. As a backup, Orpheus carries a “galvanic release” on these weights in addition to a "commandable" one. This passive release mechanism corrodes away in salt water, allowing for a reliable backup should the vehicle be unable to command weight release. Yesterday, these corrodible links released earlier than expected, likely due to a faster reaction in the warm water. As the vehicle was still attempting to maintain a low altitude off the ocean floor, and the high thruster power drained the battery. Luckily, planned fail safes prevailed: the vehicle's flashing light and iridium beacon run off different batteries, so we were able to locate and retrieve Orpheus at the water's surface. Part of the challenge -- and excitement -- of engineering at sea is responding to whatever circumstance arises, with only the resources at hand. In the image: Woods Hole Oceanographic Institution engineer Casey Machado (right) and NASA Jet Propulsion Laboratory engineer Andy Klesh (left) work on Orpheus after yesterday's recovery.