<P> On 24 March 1995, the Japanese robotic deep - sea probe Kaikō broke the depth record for unmanned probes when it reached close to the surveyed bottom of the Challenger Deep . Created by the Japan Agency for Marine - Earth Science and Technology (JAMSTEC), it was one of the few unmanned deep - sea probes in operation that could dive deeper than 6,000 metres (20,000 ft). The manometer measured depth of 10,911 m (35,797 ft) ± 3 m (10 ft) at 11 ° 22.39 ′ N 142 ° 35.54 ′ E ﻿ / ﻿ 11.37317 ° N 142.59233 ° E ﻿ / 11.37317; 142.59233 for the Challenger Deep is believed to be the most accurate measurement taken yet . Kaikō also collected sediment cores containing marine organisms from the bottom of the deep . Kaikō made many unmanned descents to the Mariana Trench during three expeditions in 1995, 1996 and 1998 . The greatest depth measured by Kaikō in 1996 was 10,898 m (35,755 ft) at 11 ° 22.10 ′ N 142 ° 25.85 ′ E ﻿ / ﻿ 11.36833 ° N 142.43083 ° E ﻿ / 11.36833; 142.43083 and in 1998 10,907 m (35,784 ft) at 11 ° 22.95 ′ N 142 ° 12.42 ′ E ﻿ / ﻿ 11.38250 ° N 142.20700 ° E ﻿ / 11.38250; 142.20700 . It was lost at sea off Shikoku Island during Typhoon Chan - Hom on 29 May 2003 . </P> <P> On 3 June 2008, the Japanese robotic deep - sea probe ABISMO (Automatic Bottom Inspection and Sampling Mobile) reached the bottom of the Mariana Trench about 150 km (93 mi) east of the Challenger Deep and collected core samples of the deep sea sediment and water samples of the water column . Created by the Japan Agency for Marine - Earth Science and Technology (JAMSTEC), it was the only unmanned deep - sea probe in use that could dive deeper than 10,000 m (32,808 ft) after that of Nereus . During ABISMO's deepest Mariana Trench dive its manometer measured a depth of 10,258 m (33,655 ft) ± 3 m (10 ft) </P> <P> On 31 May 2009 the United States sent the Nereus hybrid remotely operated vehicle (HROV) to the Challenger Deep . Nereus thus became the first vehicle to reach the Mariana Trench since 1998 and the deepest - diving vehicle then in operation . Project manager and developer Andy Bowen heralded the achievement as "the start of a new era in ocean exploration". Nereus, unlike Kaikō, did not need to be powered or controlled by a cable connected to a ship on the ocean surface . </P> <P> Nereus spent over 10 hours at the bottom of the Challenger Deep and measured a depth of 10,902 m (35,768 ft) at 11 ° 22.1 ′ N 142 ° 35.4 ′ E ﻿ / ﻿ 11.3683 ° N 142.5900 ° E ﻿ / 11.3683; 142.5900, while sending live video and data back to its mothership RV Kilo Moana at the surface and collecting geological and biological samples from the Challenger Deep bottom with its manipulator arm for further scientific analysis . </P>

Who has been to the deepest part of the ocean