2014 – RV "Falkor" –– From 16–19 December 2014, the Schmidt Ocean Institute's 2,024-ton research vessel "Falkor", under chief scientist Douglas Bartlett from the Scripps Institution of Oceanography, deployed four different untethered instruments into the Challenger Deep for seven total releases. Four landers were deployed on 16 December into the central basin: the baited video-equipped lander "Leggo" for biologics; the lander "ARI" to for water chemistry; and the probes "Deep Sound 3" and "Deep Sound 2". Both Deep Sound probes recorded acoustics floating at depth, until "Deep Sound 3" imploded at the depth of (about above the bottom) at . The "Deep Sound 2" recorded the implosion of "Deep Sound 3", providing a unique recording of an implosion within the Challenger Deep depression. In addition to the loss of the "Deep Sound 3" by implosion, the lander "ARI" failed to respond upon receiving its instruction to drop weights, and was never recovered. On 16/17 December, "Leggo" was returned to the central basin baited for amphipods. On the 17th, RV "Falkor" relocated 17 nms eastward to the eastern basin, where they again deployed both the "Leggo" (baited and with its full camera load), and the "Deep Sound 2". "Deep Sound 2" was programmed to drop to and remain at that depth during its recording of sounds within the trench. On 19 December "Leggo" landed at at a uncorrected depth of according to its pressure sensor readings. This reading was corrected to depth. "Leggo" returned with good photography of amphipods feeding on the lander’s mackerel bait and with sample amphipods. "Falknor" departed the Challenger Deep on 19 December en route the Marianas Trench Marine National Monument to the Sirena Deep. RV "Falkor" had both a Kongsberg EM302 and EM710 multibeam echosounder for bathymetry, and an Oceaneering C-Nav 3050 global navigation satellite system receiver, capable of calculating geodetic positioning with an accuracy better than horizontally and vertically.