2019 – RV "Sally Ride" –– In November 2019, as cruise SR1916, a NIOZ team led by chief scientist Hans van Haren, with Scripps technicians, deployed to the Challenger Deep aboard the 2,641-ton research vessel "Sally Ride", to recover a mooring line from the western basin of the Challenger Deep. The long mooring line in the Challenger Deep consisted of top-floatation positioned around depth, two sections of Dyneema neutrally buoyant line, two Benthos acoustic releases and two sections of self-contained instrumentation to measure and store current, salinity and temperature. Around the depth position two current meters were mounted below a long array of 100 high-resolution temperature sensors. In the lower position starting above the sea floor 295 specially designed high-resolution temperature sensors were mounted, the lowest of which was above the trench floor. The mooring line was deployed and left by the NIOZ team during the November 2016 RV "Sonne" expedition with the intention to be recovered in late 2018 by "Sonne". The acoustic commanded release mechanism near the bottom of the Challenger Deep failed at the 2018 attempt. RV "Sally Ride" was made available exclusively for a final attempt to retrieve the mooring line before the release mechanism batteries expired. "Sally Ride" arrived at the Challenger Deep on 2 November. This time a 'deep release unit' lowered by one of "Sally Ride" winch-cables to around 1,000 m depth pinged release commands and managed to contact the near-bottom releases. After being nearly three years submerged, mechanical problems had occurred in 15 of the 395 temperature sensors. The first results indicate the occurrence of internal waves in the Challenger Deep.