Editing Challenger Deep (section)

===2009 – RV ''Yokosuka''===
Cruise YK09-08 brought the JAMSTEC 4,429-ton research vessel ''Yokosuka'' back to the [[Mariana Trough]] and to the Challenger Deep June–July 2009. Their mission was a two-part program: surveying three [[hydrothermal vent]] sites in the southern Mariana Trough backarc basin near 12°57'N, 143°37'E about 130 nmi northeast of the central basin of the Challenger Deep, using the autonomous underwater vehicle ''Urashima''. AUV ''Urashima'' dives #90–94, were to a maximum depth of 3500 meters, and were successful in surveying all three sites with a Reson SEABAT7125AUV multibeam echosounder for bathymetry, and multiple water testers to detect and map trace elements spewed into the water from hydrothermal vents, white smokers, and hot spots. Kyoko OKINO from the Ocean Research Institute, University of Tokyo, was [[principal investigator]] for this aspect of the cruise.
The second goal of the cruise was to deploy a new "10K free fall camera system" called ''Ashura'', to sample sediments and biologics at the bottom of the Challenger Deep. The principal investigator at the Challenger Deep was Taishi Tsubouchi of JAMSTEC. The lander ''Ashura'' made two descents: on the first, 6 July 2009, ''Ashura'' bottomed at {{Coord|11|22.3130|N|142|25.9412|E}} at {{convert|10867|m|ft|0}}. The second descent (on 10 July 2009) was to {{Coord|11|22.1136|N|142|25.8547|E}} at {{convert|10897|m|ft|0}}. The 270&nbsp;kg ''Ashura'' was equipped with multiple baited traps, a HTDV video camera, and devices to recover sediment, water, and biological samples (mostly amphipods at the bait, and bacteria and fungus from the sediment and water samples).<ref>[http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk09-08/e yk09-08 Yokosuka Cruise Report YK09-08, Mariana Trough. June 29, 2009 – July 17, 2009] {{Webarchive|url=https://web.archive.org/web/20200727195052/http://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk09-08/e |date=27 July 2020 }} Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 31 July 2009 Yokosuka Cruise Report YK09-08</ref>