Editing Challenger Deep (section)

====2019 – ''Five Deeps Expedition / DSV Limiting Factor''====
{{main|DSV Limiting Factor}}
[[File:Limiting Factor to be prepared for a dive into the Atlantic Ocean.jpg|thumb|DSSV ''Pressure Drop'' and DSV ''Limiting Factor'' at its stern]]
[[File:Skaf and Closp shortly before a launch.jpg|thumb|The landers ''Skaff'' and ''Closp'' are prepared for a deployment during the Five Deeps Expedition.|alt=]]

The Five Deeps Expedition's objective was to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019.<ref>{{cite web|url=https://fivedeeps.com/|title=Home|website=fivedeeps.com|access-date=9 January 2019|archive-date=11 January 2019|archive-url=https://web.archive.org/web/20190111180529/https://fivedeeps.com/|url-status=live}}</ref> On 28 April 2019, explorer [[Victor Vescovo]] descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle ''Limiting Factor'' (a Triton 36000/2 model submersible).<ref>{{cite web |url=https://fivedeeps.com/home/technology/sub/ |title=Full Ocean Depth Submersible LIMITING FACTOR |work=fivedeeps.com |access-date=18 May 2019 |archive-date=14 May 2019 |archive-url=https://web.archive.org/web/20190514014338/https://fivedeeps.com/home/technology/sub/ |url-status=live }}</ref><ref name="BBC News">{{cite news |url=https://www.bbc.co.uk/news/science-environment-48230157 |title=Mariana Trench: Deepest-ever sub dive finds plastic bag |work=BBC News |date=13 May 2019 |access-date=13 May 2019 |archive-date=13 May 2019 |archive-url=https://web.archive.org/web/20190513141623/https://www.bbc.co.uk/news/science-environment-48230157 |url-status=live }}</ref> Between 28 April and 4 May 2019, the ''Limiting Factor'' completed four dives to the bottom of Challenger Deep. The fourth dive descended to the slightly less deep "Central Pool" of the Challenger Deep (crew: Patrick Lahey, Pilot; John Ramsay, Sub Designer). The Five Deeps Expedition estimated maximum depths of {{Convert|10927|m|ft|abbr=on}} ±{{Convert|8|m|ft|abbr=on}} and {{Convert|10928|m|ft|abbr=on}} ±{{Convert|10.5|m|ft|abbr=on}} at ({{Coord|11.3693|N|142.5889|E|scale:100000}}) by direct [[CTD (instrument)|CTD]] pressure measurements and a survey of the operating area by the support ship, the Deep Submersible Support Vessel ''[[USNS Indomitable (T-AGOS-7)|DSSV ''Pressure Drop'']]'', with a Kongsberg SIMRAD EM124 multibeam echosounder system. The CTD measured pressure at {{Convert|10928|m|ft|abbr=on}} of seawater depth was {{convert|1126.79|bar|MPa psi|abbr=on}}.<ref>{{cite web|url=https://fivedeeps.com/home/technology/sub/certification/|title=Full Ocean Depth Submersible DNV-GL CERTIFICATION|work=fivedeeps.com|access-date=4 May 2019|archive-date=3 November 2019|archive-url=https://web.archive.org/web/20191103145726/https://fivedeeps.com/home/technology/sub/certification/|url-status=live}}</ref><ref name="ioc-unesco.org">{{cite web|url=http://ioc-unesco.org/index.php?option=com_oe&task=viewDocumentRecord&docID=3939|title=UNESCO Technical Papers in Marine Science 44, Algorithms for computation of fundamental properties of seawater|work=ioc-unesco.org|date=1983|access-date=9 November 2019|archive-date=27 July 2020|archive-url=https://web.archive.org/web/20200727192427/http://ioc-unesco.org/index.php?option=com_oe&task=viewDocumentRecord&docID=3939|url-status=live}}</ref> Due to a technical problem the (uncrewed) [[benthic lander|ultra-deep-sea lander ''Skaff'']] used by the Five Deeps Expedition stayed on the bottom for two and half days before it was salvaged by the ''Limiting Factor'' (crew: Patrick Lahey, Pilot; Jonathan Struwe, [[DNV GL]] Specialist) from an estimated depth of {{convert|10927|m|ft|abbr=on}}.<ref>{{cite web|url=https://www.dnvgl.com/expert-story/maritime-impact/Dive-to-the-ultimate-abyss.html|title=Dive to the ultimate abyss|work=dnvgl.com|access-date=19 December 2019|archive-date=22 December 2019|archive-url=https://web.archive.org/web/20191222083907/https://www.dnvgl.com/expert-story/maritime-impact/Dive-to-the-ultimate-abyss.html|url-status=live}}</ref><ref name="ioc-unesco.org"/> The gathered data was published with the caveat that it was subject to further analysis and could possibly be revised in the future. The data will be donated to the GEBCO Seabed 2030 initiative.<ref>{{cite web |url=https://fivedeeps.com/wp-content/uploads/2019/05/FDE-Challenger-Release-FINAL-5132019.pdf |title=Deepest Submarine Dive in History, Five Deeps Expedition Conquers Challenger Deep |work=fivedeeps.com |access-date=13 May 2019 |archive-date=3 February 2020 |archive-url=https://web.archive.org/web/20200203210835/https://fivedeeps.com/wp-content/uploads/2019/05/FDE-Challenger-Release-FINAL-5132019.pdf |url-status=live }}</ref><ref name="BBC News"/><ref>{{cite web| url = https://seabed2030.gebco.net/| title = The Nippon Foundation-GEBCO Seabed 2030 Project| access-date = 19 June 2019| archive-date = 16 June 2019| archive-url = https://web.archive.org/web/20190616070107/https://seabed2030.gebco.net/| url-status = dead}}</ref><ref>{{cite web|url=https://seabed2030.gebco.net/resources_for_journalists/press_release_2019-03-11.html|title=Major partnership announced between The Nippon Foundation-GEBCO Seabed 2030 Project and The Five Deeps Expedition|date=11 March 2019|website=gebco.net|access-date=19 June 2019|archive-date=19 June 2019|archive-url=https://web.archive.org/web/20190619174227/https://seabed2030.gebco.net/resources_for_journalists/press_release_2019-03-11.html|url-status=dead}}</ref><ref>{{cite web |url=https://fivedeeps.com/home/technology/landers/ |title=Science Landers Flere, Skaff & Closp |work=fivedeeps.com |access-date=22 October 2019 |archive-date=19 July 2019 |archive-url=https://web.archive.org/web/20190719171454/https://fivedeeps.com/home/technology/landers/ |url-status=live }}</ref> Later in 2019, following a review of bathymetric data, and multiple sensor recordings taken by the DSV ''Limiting Factor'' and the ultra-deep-sea landers ''Closp'', ''Flere'' and ''Skaff'', the Five Deeps Expedition revised the maximum depth to {{Convert|10925|m|ft|abbr=on}} ±{{Convert|4|m|ft|abbr=on}}.<ref>{{cite web |url=https://fivedeeps.com/home/expedition/ |title=The Five Deeps Expedition Overview |work=fivedeeps.com |access-date=5 November 2019 |archive-date=10 June 2019 |archive-url=https://web.archive.org/web/20190610030231/https://fivedeeps.com/home/expedition/ |url-status=live }}</ref>