The Five Deeps Expedition objective was to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019. On 28 April 2019, explorer Victor Vescovo descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle "DSV Limiting Factor" (a Triton 36000/2 model submersible). 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 ± and ± at () by direct CTD pressure measurements and a survey of the operating area by the support ship, the Deep Submersible Support Vessel "DSSV Pressure Drop", with a Kongsberg SIMRAD EM124 multibeam echosounder system. The CTD measured pressure at of seawater depth was . Due to a technical problem the (unmanned) 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 . 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. 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 ±.