Kaikō ROV

in the Mariana Trench Bathymetric data obtained during the course of the expedition (December 1872 – May 1876) of the British Royal Navy survey ship enabled scientists to draw maps, Among the many discoveries of the Challenger expedition was the identification of the Challenger Deep. This depression, located at the southern end of the Mariana Trench near the Mariana Islands group, is the deepest surveyed point of the World Ocean. The Challenger scientists made the first recordings of its depth on 23 March 1875 at station 225. The reported depth was 4,475 fathoms (8184 meters) based on two separate soundings. On 23 January 1960, Don Walsh and Jacques Piccard were the first men to descend to the bottom of the Challenger Deep in the Trieste bathyscaphe. Though the initial report claimed the bathyscaphe had attained a depth of 37,800 feet, the maximum recorded depth was later calculated to be . At this depth, the water column above exerts a barometric pressure of , over one thousand times the standard atmospheric pressure at sea level. Since then, only two manned vessels have returned to the Challenger Deep: the Deepsea Challenger, which was piloted by director James Cameron on March 26, 2012, to the bottom of the trench.; and the Limiting Factor, piloted by Victor Vescovo in 2019. In March 1995, Kaikō became the second vessel ever to reach the bottom of the Challenger Deep, and the first craft to visit this location since the Trieste mission. marking the deepest dive for an unmanned submersible to date. On 31 May 2009, Nereus became the third vessel to visit the bottom of the Challenger Deep, reaching a maximum recorded depth of 10,902 meters. ==RV Kairei==

RV Kairei (かいれい) is a deep sea research vessel that served as the support ship for Kaikō, and for its replacement ROV, Kaikō7000II. It now serves as the support ship for ABISMO. Kairei uses ABISMO to conduct surveys and observations of oceanic plateaus, abyssal plains, oceanic basins, submarine volcanoes, hydrothermal vents, oceanic trenches and other underwater terrain features to a maximum depth of 11,000 meters. Kairei also conducts surveys of the structure of deep sub-bottoms with complicated geographical shapes in subduction zones using its on-board multi-channel reflection survey system.{{cite web ==Timeline and fate of Kaikō==

. , connecting measuring equipment with underwater cables on the sea floor. On this mission, another bacterial species, Shewanella violacea, was discovered at a depth of 5,110 meters.{{cite journal In late November 1999, Kaikō located the wreckage of H-2 No. 8, a NASDA rocket (satellite launch system), on the sea floor at a depth of 2,900 meters off the Ogasawara Islands. H-2 flight F8 was conducted on 15 November 1999. The rocket, which was carrying a Multi-Functional Transport Satellite (MTSAT) payload, self-destructed after experiencing an engine malfunction shortly after it was launched. In August 2000, Kaikō discovered hydrothermal vents and their associated deep sea communities at a depth of 2,450 meters near the Central Indian Ridge. The Central Indian Ridge is a divergent tectonic plate boundary between the African Plate and the Indo-Australian Plate located in the western Indian Ocean. On 29 May 2003, Kaikō was lost at sea during Typhoon Chan-Hom, when a steel secondary cable connecting it to its launcher at the surface broke off the coast of Shikoku Island. In May 2004, JAMSTEC resumed its research operations, using a converted ROV as its vehicle. The ROV, formerly known as UROV 7K, was rechristened Kaikō7000II. The 7000 designation indicates that this vessel is rated for diving to a maximum depth of 7,000 meters. ==Development of ABISMO==

While the temporary replacement ROV (Kaikō7000II) has a remarkable performance record, it is only rated to 7,000 meters and cannot reach the deepest oceanic trenches. For this reason, JAMSTEC engineers began work on a new 11,000-meter class of ROV in April 2005. The project is called ABISMO (Automatic Bottom Inspection and Sampling Mobile), which translates to abyss in Spanish. Initial sea trials of ABISMO were conducted in 2007. The craft successfully reached a planned depth of 9,760-meters, the deepest part of Izu–Ogasawara Trench, where it collected core samples of sediment from the seabed. ==See also==