 Kaikō | |
| History | |
|---|---|
 Japan | |
| Owner | TheJapan Agency for Marine-Earth Science and Technology (JAMSTEC) |
| Operator | JAMSTEC |
| Laid down | 1991[1] |
| Launched | 1993[1] |
| Christened | 1993[1] |
| Completed | 1993[1] |
| Commissioned | 1993[1] |
| Maiden voyage | May 1993 to March 1995[1] |
| Out of service | 2003 |
| Stricken | 2003 |
| Homeport | Yokosuka, Japan |
| Fate | Lost at sea offShikoku Island duringTyphoon Chan-Hom, 29 May 2003[2] |
| General characteristics | |
| Type | remotely operated underwater vehicle |
| Displacement | 10.6 tons in air[3] |
| Length | 3.0 meters[3] |
| Installed power | electrical (Lithium-ion batteries) |
| Test depth | 10911.4 meters |
| Complement | unmanned |
| Sensors & processing systems | side-scan sonar and search lights |
Kaikō (かいこう; "Ocean Trench")[4] was aremotely operated underwater vehicle (ROV) built by theJapan Agency for Marine-Earth Science and Technology (JAMSTEC) for exploration of thedeep sea.Kaikō was the second of only five vessels ever to reach the bottom of theChallenger Deep, as of 2019. Between 1995 and 2003, this 10.6 ton unmannedsubmersible conducted more than 250 dives, collecting 350 biological species (including 180 different bacteria), some of which could prove to be useful in medical and industrial applications.[3] On 29 May 2003,Kaikō was lost at sea off the coast ofShikoku Island duringTyphoon Chan-Hom, when a secondary cable connecting it to its launcher at the ocean surface broke.[2]
Another ROV,Kaikō7000II, served as the replacement forKaikō until 2007. At that time, JAMSTEC researchers begansea trials for the permanent replacement ROV,ABISMO (AutomaticBottomInspection andSamplingMobile).
Bathymetric data obtained during the course of theexpedition (December 1872 – May 1876) of the BritishRoyal Navy survey shipHMS Challenger enabled scientists to draw maps,[5] which provided a rough outline of certain majorsubmarine terrain features, such as the edge of thecontinental shelves and theMid-Atlantic Ridge. This discontinuous set of data points was obtained by the simple technique of takingsoundings by lowering long lines from the ship to theseabed.[6]
Among the many discoveries of theChallenger expedition was the identification of the Challenger Deep. This depression, located at the southern end of theMariana Trench near theMariana Islands group, is the deepestsurveyed point of theWorld Ocean. TheChallenger scientists made the first recordings of its depth on 23 March 1875 atstation 225. The reported depth was 4,475fathoms (8184 meters) based on two separate soundings.
On 23 January 1960,Don Walsh andJacques Piccard were the first men to descend to the bottom of the Challenger Deep in theTriestebathyscaphe. Though the initial report claimed the bathyscaphe had attained a depth of 37,800 feet,[7] the maximum recorded depth was later calculated to be 10,911 metres (35,797 ft). At this depth, thewater column above exerts abarometric pressure of 108.6 megapascals (15,750 psi), over one thousand times thestandard atmospheric pressure at sea level. Since then, only two manned vessels have returned to the Challenger Deep: theDeepsea Challenger, which was piloted by directorJames Cameron on March 26, 2012, to the bottom of the trench.;[8] and the Limiting Factor, piloted by Victor Vescovo in 2019.
In March 1995,Kaikō became the second vessel ever to reach the bottom of theChallenger Deep, and the first craft to visit this location since theTrieste mission.[3][9] The maximum depth measured on that dive was 10,911.4 meters,[1][9][10] marking the deepest dive for an unmanned submersible to date. On 31 May 2009,Nereus became the third vessel to visit the bottom of theChallenger Deep, reaching a maximum recorded depth of 10,902 meters.[9][11]
RVKairei (かいれい) is a deep sea research vessel that served as the support ship forKaikō, and for its replacement ROV,Kaikō7000II. It now serves as the support ship forABISMO.Kairei usesABISMO to conduct surveys and observations ofoceanic 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.[12]
In February 1996,Kaikō returned to Challenger Deep, this time collectingsediment andmicroorganisms from theseabed at a depth of 10,898 meters. Among the novel organisms identified and collected wasMoritella yayanosii[13] andShewanella benthica.[14] These two species of bacteria appear to be obligately barophilic. The optimal pressure conditions for growth ofS. benthica is 70Megapascals (MPa), whileM. yayanosii grows best at 80 MPa; no growth at all was detected at pressures of less than 50 MPa with either strain.[14] Both species appear to contain high levels ofdocosahexaenoic acid (DHA) andeicosapentaenoic acid (EPA),omega-3 fatty acids which could prove to be useful in the treatment ofhypertension and evencancer.[3]
In December 1997,Kaikō located the wreck ofTsushima Maru on the sea floor off the coast ofOkinawa.Tsushima Maru was an unmarked Japanese passenger/cargo ship that was sunk during World War II byUSS Bowfin, aUnited States Navysubmarine.
In May 1998,Kaikō returned again to Challenger Deep, this time collecting specimens ofHirondellea gigas.Hirondellea gigas (Birstein and Vinagradov, 1955) is acrustacean of theUristidaefamily ofmarineamphipods.[15]
In October 1999,Kaikō performed a robotic mechanical operation at a depth of 2,150 meters off the coast of Okinawa near theRyukyu Trench, 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.[16] This organism is notable for its brilliant violet-coloredpigment. Certain compounds found inS. violacea may have applications in thecosmetics industry (development of products for lightening of skin tone) and also in thesemiconductor industry (development of chemicals to be used in production of semiconductors).[3]
In late November 1999,Kaikō located the wreckage ofH-2 No. 8, aNASDA rocket (satellite launch system), on the sea floor at a depth of 2,900 meters off theOgasawara Islands. H-2 flight F8 was conducted on 15 November 1999. The rocket, which was carrying aMulti-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 associateddeep sea communities at a depth of 2,450 meters near theCentral Indian Ridge. The Central Indian Ridge is adivergenttectonic plateboundary between theAfrican Plate and theIndo-Australian Plate located in the westernIndian Ocean.
On 29 May 2003,Kaikō was lost at sea duringTyphoon Chan-Hom, when a steel secondary cable connecting it to its launcher at the surface broke off the coast ofShikoku Island.[2]
In May 2004, JAMSTEC resumed its research operations, using a converted ROV as its vehicle. The ROV, formerly known asUROV 7K, was rechristenedKaikō7000II. The7000 designation indicates that this vessel is rated for diving to a maximum depth of 7,000 meters.
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.[2][17] The project is calledABISMO (Automatic Bottom Inspection and Sampling Mobile), which translates toabyss in Spanish. Initial sea trials ofABISMO were conducted in 2007. The craft successfully reached a planned depth of 9,760-meters, the deepest part ofIzu–Ogasawara Trench, where it collected core samples of sediment from the seabed.[2][17]
{{cite book}}: CS1 maint: location missing publisher (link){{cite journal}}: CS1 maint: multiple names: authors list (link) Japan Agency for Marine-Earth Science and Technology vessels and vehicles | ||
|---|---|---|
Underlined vessels and vehicles are in development. Vessels and vehicles with superscriptX have retired from service. | ||
| Research vessels |  | |
| Deep-submergence vehicles | ||
| Remotely operated underwater vehicles & Autonomous underwater vehicles | ||
