Editing Challenger Deep (section)

===2017 – RV ''Kairei''===
JAMSTEC deployed ''Kairei'' to the Challenger Deep in May 2017 for the express purpose of testing the new full-ocean depth ROV ''UROV11K'' (Underwater ROV 11,000-meter-capable), as cruise KR 17-08C, under chief scientist Takashi Murashima. The cruise title was: "Sea trial of a full depth ROV ''UROV11K'' system in the Mariana Trench". ''UROV11K'' carried a new [[4K resolution|4K High Definition]] video camera system, and new sensors to monitor the hydrogen-sulfide, methane, oxygen, and hydrogen content of the water. Unfortunately, on ''UROV11K''{{'s}} ascent from {{convert|10899|m|ft|0}} (at about 11°22.30'N 142°35.8 E, in the ''eastern'' basin) on 14 May 2017, the ROV's buoyancy failed at {{convert|5320|m|ft|0}} depth, and all efforts to retrieve the ROV were unsuccessful. The rate of descent and drift is not available, but the ROV bottomed to the east of the deepest waters of the eastern basin as revealed by the ship's maneuvering on 14 May. Murashima then directed the Kairei to a location about 35 nmi east of the eastern basin of the Challenger Deep to test a new "Compact Hadal Lander" which made three descents to depths from 7,498 to 8,178 m for testing the Sony 4K camera and for photography of fish and other macro-biologics.<ref>{{cite web| url = http://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr17-08c/e| title = R/V KAIREI Final Report, KR17-08C, Sea trial of a full depth ROV 'UROV11K' system in the Mariana Trench, 2017/05/05 – 2017/05/25.| access-date = 7 December 2019| archive-date = 7 December 2019| archive-url = https://web.archive.org/web/20191207233759/http://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr17-08c/e| url-status = live}}</ref>