title: Thomas Pynchon

text: Shortly before "Against the Day" was published, Pynchon's prose appeared in the program for ""The Daily Show": Ten Fu@#ing Years (The Concert)", a retrospective on Jon Stewart's comedy-news broadcast "The Daily Show".


title: Thomas Pynchon

text: On December 6, 2006, Pynchon joined a campaign by many other major authors to clear Ian McEwan of plagiarism charges by sending a typewritten letter to his British publisher, which was published in the "Daily Telegraph" newspaper.


title: Thomas Pynchon

text: Pynchon's 2009 YouTube promotional teaser for the novel "Inherent Vice" is the second time a recording of his voice has been released to mainstream outlets (the first being his appearances on "The Simpsons").


title: Thomas Pynchon

text: In 2012, Pynchon's novels were released in e-book format, ending a long holdout by the author. Publisher Penguin Press reported that the novels' length and complex page layouts made it a challenge to convert them to a digital format. Though they had produced a promotional video for the June release, Penguin had no expectation Pynchon's public profile would change in any fashion.


title: Thomas Pynchon

text: In 2013, his son, Jackson Pynchon, graduated from Columbia University, where he was affiliated with St. Anthony Hall.


title: Thomas Pynchon

text: In September 2014, Josh Brolin told "The New York Times" that Pynchon had made a cameo in the "Inherent Vice" film adaptation. This led to a sizable online hunt for the author's appearance, eventually targeting actor Charley Morgan, whose small role as a doctor led many to believe he was Pynchon. Morgan, son of "M*A*S*H"s Harry Morgan, claimed that Paul Thomas Anderson, whom he described as a friend, had told him that such a cameo did not exist. Despite this, nothing has been directly confirmed by Anderson or Warner Bros. Pictures.


title: Thomas Pynchon

text: On November 6, 2018, Pynchon was photographed near his apartment in New York's Upper West Side district when he went to vote with his son. The photo was published by the "National Enquirer" and was said to be the first photo of him "in decades".


title: Thomas Pynchon

text: In December 2022, the Huntington Library announced that it had acquired the literary archive, including typescripts and drafts of each of Pynchon's novels, handwritten notes, correspondence with publishers, and research.


title: Family tree of the British royal family

text: This is the family tree of the British royal family, from James VI and I (who united the crowns of England and Scotland) to the present monarch, Charles III.


title: Fiat

text: Fiat Automobiles S.p.A. (, , ; originally FIAT, ) is an Italian automobile manufacturer, formerly part of Fiat Chrysler Automobiles, and since 2021 a subsidiary of Stellantis through its Italian division Stellantis Italy. Fiat Automobiles was formed in January 2007 when Fiat S.p.A. reorganized its automobile business, and traces its history back to 1899 when the first Fiat automobile, the Fiat 4 HP, was produced.


title: Fiat

text: Fiat Automobiles is the largest automobile manufacturer in Italy. During its more than century-long history, it remained the largest automobile manufacturer in Europe and the third in the world after General Motors and Ford for over 20 years, until the car industry crisis in the late 1980s. In 2013, Fiat S.p.A. was the second largest European automaker by volumes produced and the seventh in the world, while FCA was the world's eighth-largest automaker.


title: Fiat

text: In 1970, Fiat Automobiles employed more than 100,000 in Italy when its production reached the highest number, 1.4 million cars, in that country. As of 2002, it built more than 1 million vehicles at six plants in Italy and the country accounted for more than a third of the company's revenue. Fiat has also manufactured railway engines, military vehicles, farm tractors, aircraft, and weapons such as the Fiat–Revelli Modello 1914.


title: Fiat

text: Fiat-brand cars are built in several locations around the world. Outside Italy, the largest country of production is Brazil, where the Fiat brand was for many years the market leader. The group also has factories in Argentina, Poland and Mexico (where Fiat-brand vehicles are manufactured at plants owned and operated by Stellantis North America for export to the United States, Brazil, Italy and other markets) and a long history of licensing manufacture of its products in other countries.


title: Fiat

text: Fiat Automobiles has received many international awards for its vehicles, including nine European Car of the Year awards, the most of any other manufacturer, and it ranked many times as the lowest level of emissions by vehicles sold in Europe.


title: Fiat

text: On 11 July 1899, Giovanni Agnelli was part of the group of founding members of FIAT, "Fabbrica Italiana di Automobili Torino". The first Fiat plant opened in 1900 with 35 staff making 24 cars. Known from the beginning for the talent and creativity of its engineering staff, by 1903 Fiat made a small profit and produced 135 cars; this grew to 1,149 cars by 1906. The company then went public selling shares via the Milan stock exchange.


title: Fiat

text: Agnelli led the company until his death in 1945, while Vittorio Valletta administered the firm's daily activities. Its first car, the 3 ½ CV (of which only 24 copies were built, all bodied by Alessio of Turin) was based on a design purchased from Ceirano GB & C and had a boxer twin engine. In 1903, Fiat produced its first truck. In 1908, the first Fiat was exported to the US. That same year, the first Fiat aircraft engine was produced. Also around the same time, Fiat taxis became popular in Europe.


title: Fiat

text: By 1910, Fiat was the largest automotive company in Italy. That same year, a new plant was built in Poughkeepsie, NY, by the newly founded American F.I.A.T. Automobile Company. Owning a Fiat at that time was a sign of distinction. The cost of a Fiat in the US was initially $4,000 and rose up to $6,400 in 1918, compared to $825 for a Ford Model T in 1908, and $525 in 1918, respectively. During World War I, Fiat had to devote all of its factories to supplying the Allies with aircraft, engines, machine guns, trucks, and ambulances. Upon the entry of the US into the war in 1917, the factory was shut down as US regulations became too burdensome (the site was eventually sold to Western Publishing). After the war, Fiat introduced its first tractor, the 702. By the early 1920s, Fiat had a market share in Italy of 80%.


title: Fiat

text: In 1921, workers seized Fiat's plants and hoisted the red flag of communism over them. Agnelli responded by quitting the company. However, the Italian Socialist Party and its ally organization, the Italian General Confederation of Labour, in an effort to effect a compromise with the centrist parties ordered the occupation ended. In 1922, Fiat began to build the famous Lingotto car factory—then the largest in Europe—which opened in 1923. It was the first Fiat factory to use assembly lines; by 1925, Fiat controlled 87% of the Italian car market. In 1928, with the 509, Fiat included insurance in the purchase price.


title: Fiat

text: Fiat made military machinery and vehicles during World War II for the Army and "Regia Aeronautica" and later for the Germans. Fiat made fighter aircraft like the biplane CR.42 Falco, which was one of the most common Italian aircraft, along with Savoia-Marchettis, as well as light tanks (obsolete compared to their German and Soviet counterparts) and armored vehicles. The best Fiat aircraft was the G.55 fighter, which arrived too late and in too limited numbers. In 1943, the year Benito Mussolini was overthrown, the National Liberation Committee removed the Agnelli family from leadership roles in Fiat because of its ties to Mussolini's government. They were not returned until 1963, when Giovanni's grandson, Gianni, took over as general manager until 1966, as chairman until 1996.


title: Fiat

text: In 1970, Fiat employed more than 100,000 in Italy when its production reached the highest number, 1.4 million cars, in that country. As of 2002, Fiat built more than 1 million vehicles at six plants in Italy and the country accounted for more than a third of the company's revenue.


title: Fiat

text: Towards the end of 1976, it was announced that the Libyan government was to take a shareholding in the company in return for a capital injection. Other aspects of the Libyan agreement included the construction of a truck and bus plant at Tripoli. Chairman Agnelli candidly described the deal as "a classic petro-money recycling operation which will strengthen the Italian reserves, provide Fiat with fresh capital and give the group greater tranquility in which to carry out its investment programmes".


title: Fiat

text: On 29 January 2014, it was announced that Fiat S.p.A. (the former owner of Fiat Group) was to be merged into a new Netherlands-based holding company Fiat Chrysler Automobiles NV (FCA), took place before the end of 2014. Fiat Chrysler Automobiles became the new owner of Fiat Group. On 1 August 2014, Fiat S.p.A. received necessary shareholder approval to proceed with the merger, which became effective 12 October 2014. FCA then merged with the French manufacturer PSA Group in 2019, with the new conglomerate being named Stellantis in 2020.


title: Fiat

text: Fiat's main market is Europe, mainly focused in Italy. Historically successful in building city cars and Superminis, currently Fiat has a range of models focused on those two segments (accounting for the 84% of its sales in 2011). Fiat does not currently offer any large family car, nor an executive car: these market segments are to some extent covered by the Lancia and Alfa Romeo brands, which Fiat also owns.


title: Fiat

text: Fiat's share of the European market shrank from 9.4 percent in 2000 to 5.8 percent in the summer of 2004. At this point Sergio Marchionne was appointed as Fiat's chief executive. By March 2009 their market share had expanded to 9.1 percent.


title: Fiat

text: Fiat built their five-storey Lingotto plant between 1915 and 1918, at which time it was Europe's largest car manufacturing plant. Later the Mirafiori plant was built, also in Turin. To prepare for production of the all-new Fiat 128, Fiat opened their Rivalta plant in October 1968. Until the 128 entered production, the plant was used to build sports versions of the 850 and 124 as well as parts for the Fiat Dino.


title: Fiat

text: Fiat's 2018 range of passenger car engines comprised eleven units, eight petrols and three diesels. Their current range of models is the following:


title: Fiat

text: Fiat was already exporting cars to the UK market by the outbreak of World War II in 1939. Its market share increased rapidly during the 1970s, with the 127 supermini and 128 range of small family cars being the biggest sellers, selling largely on practicality and efficiency. Fiat's market share increased further during the 1980s with the Fiat Uno (imported to the UK from June 1983) being the company's best-seller in the UK, and its share fell sharply in the early 1990s before the arrival of the Punto in March 1994 rejuvenated the company's UK fortunes.


title: Fiat

text: The second-generation Punto was a strong seller in the UK after its October 1999 launch, but the new modern-day Fiat 500 (launched there in January 2008) has accounted for most of the company's UK sales in more recent years. The original Fiat 500 had been one of the few direct competitors for the iconic Mini during its 1960s heyday.


title: Fiat

text: Fiat has invested for a long time in South America, mainly in Brazil (where has been the market leader for many years) and in Argentina. They built their first Brazilian car plant in the Greater Belo Horizonte city of Betim in 1973, after having begun by building tractors there.


title: Fiat

text: The Brazilian range is similar to the European one, with the addition of a special family which derives from a common platform (called "Project 178"): Palio, Siena, Palio Weekend and Strada.


title: Fiat

text: Recently a range of new models developed in Brazil has been launched: Pulse, Fiorino, Toro, Argo, and Mobi.


title: Fiat

text: Other European models are currently imported to Brazil: 500e, imported from Italy, and Cronos, imported from Argentina.


title: Fiat

text: Fiat has a long history in the United States. In 1908, the Fiat Automobile Co. was established in the country and a plant in Poughkeepsie, N.Y., began producing Fiats a year later, like the Fiat 60 HP and the Fiat 16-20 HP. These luxury cars were produced long before Chrysler Corp. was formed in 1925 from older manufacturers that were acquired by Walter P. Chrysler, the founder. The New Jersey factory was closed after the U.S. entered World War I in 1917.


title: Fiat

text: Fiat returned to North America in the 1950s, selling the original 500, Fiat 600 Multipla, Fiat 1100, Fiat 1200, and the Fiat 1300. Models produced from the 1960s onward include the Fiat 124 Sport Spider and the Fiat X1/9 - these two sporting cars remained rather successful in the United States market, which took nearly sixty percent of the total production in 1980. Fiat gained a reputation for selling poor quality cars in North America, mostly over rust and poor reliability. The last new Fiat model to be introduced in North America during this era was the Strada, in February 1979. Sales in the US fell accordingly, from a high of 100,511 cars in 1975 to 14,113 in 1982. Accordingly, Fiat left the United States car market in 1983, although the Spider and the X1/9 continued to be sold in small numbers with Pininfarina and Bertone badging respectively.


title: Fiat

text: In January 2009, the Fiat Group acquired a 20% stake in US automaker Chrysler LLC. The deal saw the return of the Fiat brand to North America after a 25-year absence. The first Fiat-branded model to appear was the internationally popular Fiat 500 city car. The Fiat 500 model is built at Chrysler's assembly plant in Toluca, Mexico, which currently makes also the Dodge Journey and Fiat Freemont crossovers. Fiat is also selling their commercial vehicles Fiat Ducato and Fiat Doblò in North America, rebranded as Ram ProMaster and Ram ProMaster City respectively.


title: Fiat

text: FIAT discontinued production of the Fiat 500 in 2019 while sales of leftover dealer stock continued into 2020. FIAT also discontinued the 124 spider and 500l models in 2020. FIAT has announced a new car to be released a new 500e to launch in 2024.


title: Fiat

text: Fiat passenger cars began assembly in South Africa in 1950, and full production in their Rosslyn plant commenced in 1966. Sales reached a peak market share of about five percent around 1970 but then dropped precipitously. A new 128-based half-ton pickup truck helped turn the situation around.


title: Fiat

text: It also assembled in Egypt through El-Nasr Automotive Manufacturing Company which assembled FIAT brands 125-127-128.


title: Fiat

text: On 13 October 2022, Fiat Brand and the Algerian government signed a framework agreement aimed at local production of vehicles and the development of the automotive sector in Algeria.


title: Fiat

text: Fiat's presence in the Chinese market is limited compared to its European, Japanese, Korean, and American rivals. At the beginning of 2012, Fiat was only importing Fiat Bravo and Fiat 500 model. However, in 2012 Fiat and GAC opened a joint venture plant to produce the first Fiat vehicle specifically developed for the Chinese market ever: the Fiat Viaggio, a compact car derived from another Fiat model, the Dodge Dart (in turn derived from another Fiat car, the Alfa Romeo Giulietta).


title: Fiat

text: Fiat currently offers to Japanese consumers the 500 in both coupe and convertible body styles, and the Panda.


title: Fiat

text: Fiat has been present in the Indian market since 1948 in a joint venture with Tata Motors, although current car sales are limited and directed at niche markets (approx. 20k units in 2011). The currently offered models are the Fiat Punto and the Fiat Linea.


title: Fiat

text: The Fiat 500 (, ) is a car produced by the Fiat company of Italy between 1957 and 1975, with limited production of the Fiat 500 K estate continuing until 1977. The car was designed by Dante Giacosa. Redesigned in 2007, it is currently distributed worldwide.


title: Fiat

text: The Fiat Panda is a city car from the Italian automotive manufacturer Fiat. The current version is the third one distributed as from 2012.


title: Fiat

text: The Fiat 500L enlarges, as from September 2012, the Fiat 500 family with a Mini MPV which replace the Fiat Idea. The model is produced in the new Fiat plant in Serbia. The platform is the same of the Fiat Punto.


title: Fiat

text: The European Car of the Year award has been awarded twelve times to the Fiat Group over the last forty years, more than any other manufacturer. Nine of these awards were won by Fiat Automobiles models. Fiat models awarded the title:


title: Fiat

text: Fiat Automobiles, one of Europe's 10 best-selling automotive brands, has for the second year running been confirmed as having the lowest average value for CO emissions from vehicles sold in 2008: 133.7 g/km (137.3 g/km in 2007). This was corroborated by JATO, a provider of automotive data.


title: Fiat

text: Fiat started development of electric vehicles back in the mid 1970s, with the concept Fiat X1/23. More recently in 2008, Fiat showed the Phylla concept, and the Fiat Bugster concept in Brazil.


title: Fiat

text: Fiat joined utility companies Cemig and Itaipu to develop new electric vehicles for Brazil, with production in 2009 of the Palio Weekend Electric.


title: Fiat

text: Fiat launched the electric 500e, a compliance car, in California in 2013, but no sales were planned for Europe. Fiat CEO Sergio Marchionne claimed in 2014 that each one was sold at a loss of $14,000.


title: Fiat

text: In 2016, after Tesla had announced the Model 3 and had a high number of reservations for the electric car, Marchionne questioned whether Tesla could produce the cars and be profitable. He then stated that "if Tesla CEO Elon Musk can demonstrate that the car will be profitable at that price, I will copy the formula, add the Italian design flair, and get it to the market within 12 months."


title: Fiat

text: In 1971, the Fiat 124 Sport Spider was prepared for the World Rally Championship when Abarth became involved with its production and development and from 1972 had relative success with two wins in 1972, one in 1973 and won 1st, 2nd and 3rd in the 1974 Portuguese TAP Rally.


title: Fiat

text: The Fiat 131 Abarth was a very successful rally car replacing the 124. Between 1976 and 1981 the Fiat 131 won 18 World Rally Championship events, resulting in winning the WRC Drivers Championship two times: in 1978, and in 1980, and winning the WRC Constructors Championship three times: in 1977, 1978, and in 1980.


title: Fiat

text: Lancia took over the role of motorsport for the Fiat Group during the 1980s. After a long break of factory-supported entries, in 2003 a Fiat Punto S1600 won the Italian Rally Championship, and 2006 the Fiat Grande Punto S2000 won the FIA European Rally Championship, followed by three successive wins in 2009, 2010 and 2011.


title: Fiat

text: The FIAT initials were first used in the distinctive logo form in 1901. Beginning in 1931, the company began using a single red shield without a wreath. In 1968 the "rhomboid" logo (as it was known internally) was introduced which featured the FIAT initials spelled out on four interconnected rhombuses. The rhomboid was slowly phased in during the early 1970s, although the older "laurel wreath" style FIAT badge was used to denote sporting models such as the 124 Spider, 127 Sport, X1/9, and the tuned Abarth models. A new corporate nose based on the rhomboid logo was first introduced in 1983 on the Uno, which consisted of five chrome bars inclined at an angle of 18 degrees to mirror the rhomboid, which usually appeared in reduced size at the corner of the grille.


title: Fiat

text: Fiat launched its Motor Village flagship store concept in 2006, with its Mirafiori Motor Village in Turin, followed by London's on Wigmore Street in 2008 and Paris's on the Champs-Élysées in 2010.


title: Fiat

text: In 2009, BSM (the British School of Motoring) ended a 16-year relationship with Vauxhall Motors and signed a deal with Fiat UK to swap its learner vehicle from the Vauxhall Corsa to the new Fiat 500. Fiat UK were expected to supply 14,000 cars to BSM over four years in a marketing deal.


title: Challenger Deep

text: The Challenger Deep is the deepest-known point of the seabed of Earth, with a depth of by direct measurement from deep-diving submersibles, remotely operated underwater vehicles and benthic landers, and (sometimes) slightly more by sonar bathymetry.


title: Challenger Deep

text: The Challenger Deep is located in the western Pacific Ocean, at the southern end of the Mariana Trench, near the Mariana Islands. According to the August 2011 version of the GEBCO Gazetteer of Undersea Feature Names, the Challenger Deep is deep at .


title: Challenger Deep

text: The depression is named after the British Royal Navy survey ship , whose expedition of 1872–1876 made the first recordings of its depth. The high water pressure at this depth makes designing and operating exploratory craft difficult. The first descent by any vehicle was by Jacques Piccard and Don Walsh in the manned bathyscaphe "Trieste" in January 1960; unmanned visits followed in 1996, 1998 and 2009. In March 2012 a manned solo descent was made by film director James Cameron in the deep-submergence vehicle "Deepsea Challenger". Between 28 April and 4 May 2019, the DSV Limiting Factor completed four manned dives to the bottom of Challenger Deep. Between 6 June and 26 June 2020, the DSV "Limiting Factor" added six completed dives during the first Ring of Fire Expedition. The deep-sea submersible "Fendouzhe" (奋斗者, "Striver") completed a crewed dive to the bottom of the Challenger Deep on 10 November 2020 with three scientists onboard whilst livestreaming the descent. Between 1 March and 13 April 2021, the DSV "Limiting Factor's" second Ring of Fire Expedition added five completed dives. During the third Ring of Fire Expedition in the summer of 2022, the DSV "Limiting Factor" made an additional nine descents to the Challenger Deep. As of July 2022 the list of people who descended to Challenger Deep includes twenty-seven people.


title: Challenger Deep

text: The Challenger Deep is a relatively small slot-shaped depression in the bottom of a considerably larger crescent-shaped oceanic trench, which itself is an unusually deep feature in the ocean floor. The Challenger Deep consists of three basins, each long, wide, and over in depth, oriented in echelon from west to east, separated by mounds between the basins higher. The three basins feature extends about west to east if measured at the isobath. Both the western and eastern basins have recorded depths (by sonar bathymetry) in excess of , while the center basin is slightly shallower. The closest land to the Challenger Deep is Fais Island (one of the outer islands of Yap), southwest, and Guam, to the northeast.


title: Challenger Deep

text: Detailed sonar mapping of the western, center and eastern basins in June 2020 by the DSSV "Pressure Drop" combined with crewed descents revealed that they undulate with slopes and piles of rocks above a bed of pelagic ooze. This conforms with the description of Challenger Deep as consisting of an elongated seabed section with distinct sub-basins or sediment-filled pools.


title: Challenger Deep

text: Over many years, the search for, and investigation of, the location of the maximum depth of the world's oceans has involved many different vessels, and continues into the twenty-first century.


title: Challenger Deep

text: The accuracy of determining geographical location, and the beamwidth of (multibeam) echosounder systems, limits the horizontal and vertical bathymetric sensor resolution hydrographers can obtain from onsite data. This is especially important when sounding in deep water, as the resulting footprint of an acoustic pulse gets large once it reaches a distant sea floor. Further, sonar operation is affected by variations in sound speed, particularly in the vertical plane. The speed is determined by the water's bulk modulus, mass, and density. The bulk modulus is affected by temperature, pressure, and dissolved impurities (usually salinity).


title: Challenger Deep

text: In 1875, during her transit from the Admiralty Islands in the Bismarck Archipelago to Yokohama in Japan, the three-masted sailing corvette HMS ""Challenger" "attempted to make landfall at Spanish Marianas (now Guam), but was set to the west by "baffling winds" preventing them from "visiting either the Carolines or the Ladrones." Their altered path took them over the undersea canyon which later became known as the Challenger Deep. Depth soundings were taken by Baillie-weighted marked rope, and geographical locations were determined by celestial navigation (to an estimated accuracy of two nautical miles). One of their samples was taken within fifteen miles of the deepest spot in all of Earth's oceans. On 23 March 1875, at sample station number #225, HMS "Challenger" recorded the bottom at deep, (the deepest sounding of her three-plus-year eastward circumnavigation of the Earth) at – and confirmed it with a second sounding at the same location. The serendipitous discovery of Earth’s deepest depression by history’s first major scientific expedition devoted entirely to the emerging science of oceanography, was incredibly good fortune, and especially notable when compared to the Earth’s third deepest site (the Sirena Deep only 150 nautical miles east of the Challenger Deep), which would remain undiscovered for another 122 years.


title: Challenger Deep

text: Seventy-five years later, the 1,140-ton British survey vessel "HMS Challenger II", on her three-year westward circumnavigation of Earth, investigated the extreme depths southwest of Guam reported in 1875 by her predecessor, HMS "Challenger". On her southbound track from Japan to New Zealand (May–July 1951), "Challenger II" conducted a survey of the Marianas Trench between Guam and Ulithi atoll, using seismic-sized bomb-soundings and recorded a maximum depth of . The depth was beyond "Challenger II" echo sounder capability to verify, so they resorted to using a taut wire with "140 lbs of scrap iron", and documented a depth of .


title: Challenger Deep

text: In New Zealand, the "Challenger II" team gained the assistance of the Royal New Zealand Dockyard, "who managed to boost the echo sounder to record at the greatest depths". They returned to the "Marianas Deep" (sic) in October 1951. Using their newly improved echo sounder, they ran survey lines at right angles to the axis of the trench and discovered "a considerable area of a depth greater than " – later identified as the Challenger Deep’s "western" basin. The greatest depth recorded was , at . Navigational accuracy of several hundred meters was attained by celestial navigation and LORAN-A. Note that the term "Challenger Deep" came into use after this 1951–52 "Challenger" circumnavigation, and commemorates both British ships of that name involved with the discovery of the deepest basin of the world’s oceans.


title: Challenger Deep

text: In August 1957, the 3,248-ton Vernadsky Institute of Geochemistry research vessel recorded a maximum depth of at in the western basin of the Challenger Deep during a brief transit of the area on Cruise #25. She returned in 1958, Cruise #27, to conduct a detailed single beam bathymetry survey involving over a dozen transects of the Deep, with extensive examination of the western basin and a quick peek into the eastern basin. Fisher records a total of three "Vityaz" sounding locations on Fig.2 "Trenches" (1963), one within yards of the 142°11.5' E location, and a third at , all with depth. The depths were considered statistical outliers, and a depth greater than 11,000 m has never been proven. Taira reports that if "Vityaz" depth was corrected with the same methodology used by the Japanese RV "Hakuho Maru" expedition of December 1992, it would be presented as , as opposed to modern depths from multibeam echosounder systems greater than with the NOAA accepted maximum of in the western basin.


title: Challenger Deep

text: The first definitive verification of both depth and location of the Challenger Deep (western basin) was determined by Dr. R. L. Fisher from the Scripps Institution of Oceanography, aboard the 325-ton research vessel "Stranger". Using explosive soundings, they recorded at/near in July 1959. "Stranger" used celestial and LORAN-C for navigation. LORAN-C navigation provided geographical accuracy of or better. According to another source RV "Stranger" using bomb-sounding surveyed a maximum depth of at . Discrepancies between the geographical location (lat/long) of "Stranger" deepest depths and those from earlier expeditions ("Challenger II" 1951; "Vityaz" 1957 and 1958) "are probably due to uncertainties in fixing the ships' positions". "Stranger" north-south zig-zag survey passed well to the east of the eastern basin southbound, and well to the west of the eastern basin northbound, thus failed to discover the eastern basin of the Challenger Deep. The maximum depth measured near longitude 142°30’E was , about 10 km west of the eastern basin’s deepest point. This was an important gap in information, as the eastern basin was later reported as deeper than the other two basins.


title: Challenger Deep

text: "Stranger" crossed the center basin twice, measuring a maximum depth of in the vicinity of 142°22’E. At the western end of the central basin (approximately 142°18’E), they recorded a depth of .


title: Challenger Deep

text: The western basin received four transects by "Stranger", recording depths of toward the central basin, near where "Trieste" dove in 1960 (vicinity , and where "Challenger II", in 1950, recorded . At the far western end of the "western" basin (about 142°11’E), the "Stranger" recorded , some 6 km south of the location where "Vityaz" recorded in 1957–1958. Fisher stated: "differences in the "Vitiaz" [sic] and "Stranger"–"Challenger II" depths can be attributed to the [sound] velocity correction function used".


title: Challenger Deep

text: After investigating the Challenger Deep, "Stranger" proceeded to the Philippine Trench and transected the trench over twenty times in August 1959, finding a maximum depth of , and thus established that the Challenger Deep was about deeper than the Philippine Trench. The 1959 "Stranger" surveys of the Challenger Deep and of the Philippine Trench informed the U.S. Navy as to the appropriate site for "Trieste" record dive in 1960.


title: Challenger Deep

text: The "Proa Expedition, Leg 2", returned Fisher to the Challenger Deep on 12–13 April 1962 aboard the Scripps research vessel "Spencer F. Baird" (formerly the steel-hulled US Army large tug "LT-581") and employed a Precision Depth Recorder (PDR) to verify the extreme depths previously reported. They recorded a maximum depth of (location not available). Additionally, at location "H-4" in the Challenger Deep, the expedition cast three taut-wire soundings: on 12 April, the first cast was to 5,078 fathoms (corrected for wire angle) at in the central basin (Up until 1965, US research vessels recorded soundings in fathoms). The second cast, also on 12 April, was to 5,000 fathoms at in the central basin. On 13 April, the final cast recorded 5,297 fathoms (corrected for wire angle) at (the western basin). They were chased off by a hurricane after only two days on-site. Once again, Fisher entirely missed the eastern basin of the Challenger Deep, which later proved to contain the deepest depths.


title: Challenger Deep

text: The Scripps Institution of Oceanography deployed the 1,490-ton Navy-owned, civilian-crewed research vessel "Thomas Washington" (AGOR-10) to the Mariana Trench on several expeditions from 1975 to 1986. The first of these was the "Eurydice Expedition, Leg 8" which brought Fisher back to the Challenger Deep’s western basin from 28–31 March 1975. "Thomas Washington" established geodetic positioning by (SATNAV) with Autolog Gyro and EM Log. Bathymetrics were by a 12 kHz Precision Depth Recorder (PDR) with a single 60° beam. They mapped one, "possibly two", axial basins with a depth of . Five dredges were hauled 27–31 March, all into or slightly north of the deepest depths of the western basin. Fisher noted that this survey of the Challenger Deep (western basin) had "provided nothing to support and much to refute recent claims of depths there greater than ." While Fisher missed the eastern basin of the Challenger Deep (for the third time), he did report a deep depression about 150 nautical miles east of the western basin. The 25 March dredge haul at encountered , which pre-shadowed by 22 years the discovery of HMRG Deep/Sirena Deep in 1997. The deepest waters of the HMRG Deep/Serina Deep at are centered at/near , approximately 2.65 km from Fisher's 25 March 1975 dredge haul.


title: Challenger Deep

text: On Scripps Institution of Oceanography's "INDOPAC Expedition Leg 3", the chief scientist, Dr. Joseph L. Reid, and oceanographer Arnold W. Mantyla made a hydrocast of a free vehicle (a special-purpose benthic lander (or "baited camera") for measurements of water temperature and salinity) on 27 May 1976 into the western basin of the Challenger Deep, "Station 21", at at about depth. On "INDOPAC Expedition Leg 9", under chief scientist A. Aristides Yayanos, "Thomas Washington" spent nine days from 13–21 January 1977 conducting an extensive and detailed investigation of the Challenger Deep, mainly with biological objectives. "Echo soundings were carried out primarily with a 3.5 kHz single-beam system, with a 12 kHz echosounder operated in addition some of the time" (the 12 kHz system was activated for testing on 16 January). A benthic lander was put into the western basin () on 13 January, bottoming at and recovered 50 hours later in damaged condition. Quickly repaired, it was again put down on the 15th to depth at . It was recovered on the 17th with excellent photography of amphipods (shrimp) from the Challenger Deep’s western basin. The benthic lander was put down for the third and last time on the 17th, at , in the central basin at a depth of . The benthic lander was not recovered and may remain on the bottom in the vicinity of . Free traps and pressure-retaining traps were put down at eight location from 13 to 19 January into the western basin, at depths ranging from . Both the free traps and the pressure-retaining traps brought up good sample amphipods for study. While the ship briefly visited the area of the eastern basin, the expedition did not recognize it as potentially the deepest of the three Challenger Deep basins.


title: Challenger Deep

text: "Thomas Washington" returned briefly to the Challenger Deep on 17–19 October 1978 during "Mariana Expedition Leg 5" under chief scientist James W. Hawkins. The ship tracked to the south and west of the eastern basin, and recorded depths between . Another miss. On "Mariana Expedition Leg 8", under chief scientist Yayanos, "Thomas Washington" was again involved, from 12–21 December 1978, with an intensive biological study of the western and central basins of the Challenger Deep. Fourteen traps and pressure-retaining traps were put down to depths ranging from ; the greatest depth was at . All of the 10,900-plus m recordings were in the western basin. The depth was furthest east at 142°26.4' E (in the central basin), about 17 km west of the eastern basin. Again, focused efforts on the known areas of extreme depths (the western and central basins) was so tight that the eastern basin again was missed by this expedition.


title: Challenger Deep

text: From 20 to 30 November 1980, "Thomas Washington" was on site at the western basin of the Challenger Deep, as part of "Rama Expedition Leg 7", again with chief-scientist Dr. A. A. Yayanos. Yayanos directed "Thomas Washington" in arguably the most extensive and wide-ranging of all single-beam bathymetric examinations of the Challenger Deep ever undertaken, with dozens of transits of the western basin, and ranging far into the backarc of the Challenger Deep (northward), with significant excursions into the Pacific Plate (southward) and along the trench axis to the east. They hauled eight dredges in the western basin to depths ranging from , and between hauls, cast thirteen free vertical traps. The dredging and traps were for biological investigation of the bottom. In the first successful retrieval of a live animal from the Challenger Deep, on 21 November 1980 in the western basin at , Yayanos recovered a live amphipod from about 10,900 meters depth with a pressurized trap. Once again, other than a brief look into the eastern basin, all bathymetric and biological investigations were into the western basin.


title: Challenger Deep

text: On Leg 3 of the Hawaii Institute of Geophysics' (HIG) expedition 76010303, the 156-foot research vessel "Kana Keoki" departed Guam primarily for a seismic investigation of the Challenger Deep area, under chief scientist Donald M. Hussong. The ship was equipped with air guns (for seismic reflection soundings deep into the Earth's mantle), magnetometer, gravimeter, 3.5 kHz and 12 kHz sonar transducers, and precision depth recorders. They ran the Deep from east to west, collecting single beam bathymetry, magnetic and gravity measurements, and employed the air guns along the trench axis, and well into the backarc and forearc, from 13 to 15 March 1976. Thence they proceeded south to the Ontong Java Plateau. All three deep basins of the Challenger Deep were covered, but "Kana Keoki" recorded a maximum depth of . Seismic information developed from this survey was instrumental in gaining an understanding of the subduction of the Pacific Plate under the Philippine Sea Plate. In 1977, "Kana Keoki" returned to the Challenger Deep area for wider coverage of the forearc and backarc.


title: Challenger Deep

text: The Hydrographic Department, Maritime Safety Agency, Japan (JHOD) deployed the newly commissioned 2,600-ton survey vessel "Takuyo" (HL 02) to the Challenger Deep 17–19 February 1984. "Takuyo" was the first Japanese ship to be equipped with the new narrowbeam SeaBeam multi-beam sonar echosounder, and was the first survey ship with multi-beam capability to survey the Challenger Deep. The system was so new that JHOD had to develop their own software for drawing bathymetric charts based on the SeaBeam digital data. In just three days, they tracked 500 miles of sounding lines, and covered about 140 km of the Challenger Deep with multibeam ensonification. Under chief scientist Hideo Nishida, they used CTD temperature and salinity data from the top of the water column to correct depth measurements, and later conferred with Scripps Institution of Oceanography (including Fisher), and other GEBCO experts to confirm their depth correction methodology. They employed a combination of NAVSAT, LORAN-C and OMEGA systems for geodetic positioning with accuracy better than . The deepest location recorded was at ; for the first time documenting the eastern basin as the deepest of the three en echelon pools. In 1993, GEBCO recognized the report as the deepest depth of the world’s oceans. Technological advances such as improved multi-beam sonar would be the driving force in uncovering the mysteries of the Challenger Deep into the future.


title: Challenger Deep

text: The Scripps research vessel "Thomas Washington" returned to the Challenger Deep in 1986 during the "Papatua Expedition, Leg 8", mounting one of the first commercial multi-beam echosounders capable of reaching into the deepest trenches, i.e. the 16-beam Seabeam "Classic". This allowed chief scientist Yayanos an opportunity to transit the Challenger Deep with the most modern depth-sounding equipment available. During the pre-midnight hours of 21 April 1986, the multibeam echosounder produced a map of the Challenger Deep bottom with a swath of about 5–7 miles wide. The maximum depth recorded was (location of depth is not available). Yayanos noted: "The lasting impression from this cruise comes from the thoughts of the revolutionary things that Seabeam data can do for deep biology."


title: Challenger Deep

text: On 22 August 1988, the U.S. Navy-owned 1,000-ton research vessel "Moana Wave" (AGOR-22), operated by the Hawaii Institute of Geophysics (HIG), University of Hawaii, under the direction of chief scientist Robert C. Thunell from the University of South Carolina, transited northwesterly across the central basin of the Challenger Deep, conducting a single-beam bathymetry track by their 3.5 kHz narrow (30-degs) beam echosounder with a Precision Depth Recorder. In addition to sonar bathymetry, they took 44 gravity cores and 21 box cores of bottom sediments. The deepest echosoundings recorded were , with the greatest depth at 11°22′N 142°25′E in the central basin. This was the first indication that all three basins contained depths in excess of .


title: Challenger Deep

text: The 3,987-ton Japanese research vessel "Hakuhō Maru", an Ocean Research Institute – University of Tokyo sponsored ship, on cruise KH-92-5 cast three Sea-Bird SBE-9 ultra-deep CTD (conductivity-temperature-depth) profilers in a transverse line across the Challenger Deep on 1 December 1992. The center CTD was located at , in the eastern basin, at by the SeaBeam depth recorder and by the CTD. The other two CTDs were cast 19.9 km to the north and 16.1 km to the south. "Hakuhō Maru" was equipped with a narrow beam SeaBeam 500 multi-beam echosounder for depth determination, and had an Auto-Nav system with inputs from NAVSAT/NNSS, GPS, Doppler Log, EM log and track display, with a geodetic positioning accuracy approaching . When conducting CTD operations in the Challenger deep, they used the SeaBeam as a single beam depth recorder. At the corrected depth was , and at the depth was ; both in the "eastern" basin. This may demonstrate that the basins might not be flat sedimentary pools but rather undulate with a difference of or more. Taira revealed, "We considered that a trough deeper that "Vitiaz" record by was detected. There is a possibly that a depth exceeding with a horizontal scale less that the beam width of measurements exists in the Challenger Deep. Since each SeaBeam 2.7-degree beam width sonar ping expands to cover a circular area about in diameter at depth, dips in the bottom that are less than that size would be difficult to detect from a sonar-emitting platform seven miles above.


title: Challenger Deep

text: For most of 1995 and into 1996, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) employed the 4,439-ton Research Vessel "Yokosuka" to conduct the testing and workup of the 11,000 meter remotely-operated vehicle (ROV) "Kaikō", and the 6,500 meter ROV "Shinkai." It was not until February 1996, during "Yokosuka" cruise Y96-06, that "Kaikō" was ready for its first full depth dives. On this cruise, JAMSTEC established an area of the Challenger Deep (11°10'N to 11°30'N, by 141°50'E to 143°00'Ewhich later was recognized as containing three separate pools/basins en echelon, each with depths in excess of ) toward which JAMSTEC expeditions would concentrate their investigations for the next two decades. The Yokosuka employed a 151-beam SeaBeam 2112 12 kHz multibeam echosounder, allowing search swaths 12–15 km in width at depth. The depth accuracy of "Yokosuka" Seabeam was about 0.1% of water depth (i.e. ± for depth). The ship's dual GPS systems attained geodetic positioning within double digit meter ( or better) accuracy.


title: Challenger Deep

text: Cruise KR98-01 sent JAMSTEC's two-year-old the 4,517-ton Deep Sea Research Vessel RV "Kairei" south for a quick but thorough depth survey of the Challenger Deep, 11–13 January 1998, under chief scientist Kantaro Fujioka. Tracking largely along the trench axis of 070–250° they made five 80-km bathymetric survey tracks, spaced about 15-km apart, overlapping their SeaBeam 2112-004 (which now allowed sub-bottom profiling penetrating as much as 75 m below the bottom) while gaining gravity and magnetic data covering the entire Challenger Deep: western, central, and eastern basins.


title: Challenger Deep

text: "Kairei" returned in May 1998, cruise KR98-05, with ROV "Kaikō", under the direction of chief scientist Jun Hashimoto with both geophysical and biological goals. Their bathymetric survey from 14–26 May was the most intensive and thorough depth and seismic survey of the Challenger Deep performed to date. Each evening, "Kaikō" deployed for about four hours of bottom time for biological-related sampling, plus about seven hours of vertical transit time. When "Kaikō" was onboard for servicing, "Kairei" conducted bathymetric surveys and observations. "Kairei" gridded a survey area about 130 km N–S by 110 km E–W. "Kaikō" made six dives (#71–75) all to the same location, (11°20.8' N, 142°12.35' E), near the bottom contour line in the western basin.


title: Challenger Deep

text: The regional bathymetric map made from the data obtained in 1998 shows that the greatest depths in the eastern, central, and western depressions are , , and , respectively, making the eastern depression the deepest of the three.


title: Challenger Deep

text: In 1999, "Kairei" revisited the Challenger Deep during cruise KR99-06. The results of the 1998–1999 surveys include the first recognition that the Challenger Deep consists of three "right-stepping en echelon individual basins bounded by the depth contour line. The size of [each of] the deeps are almost identical, 14–20 km long, 4 km wide". They concluded with the proposal "that these three individual elongated deeps constitute the 'Challenger Deep', and [we] identify them as the East, Central and West Deep. The deepest depth we obtained during the swath mapping is in the West Deep (11°20.34' N, 142°13.20 E)." The depth was "obtained during swath mapping ... confirmed in both N–S and E-W swaths." Speed of sound corrections were from XBT to , and CTD below .


title: Challenger Deep

text: The cross track survey of the 1999 "Kairei" cruise shows that the greatest depths in the eastern, central, and western depressions are , , and , respectively, which supports the results of the previous survey.


title: Challenger Deep

text: In 2002 "Kairei" revisited the Challenger Deep 16–25 October 2002, as cruise KR02-13 (a cooperative Japan-US-South Korea research program) with chief scientist Jun Hashimoto in charge; again with Kazuyoshi Hirata managing the ROV "Kaikō" team. On this survey, the size of each of the three basins was refined to 6–10 km long by about 2 km wide and in excess of deep. In marked contrast to the "Kairei" surveys of 1998 and 1999, the detailed survey in 2002 determined that the deepest point in the Challenger Deep is located in the eastern basin around , with a depth of , located about southeast of the deepest site determined by the survey vessel "Takuyo" in 1984. The 2002 surveys of both the western and eastern basins were tight, with especially meticulous cross-gridding of the eastern basin with ten parallel tracks N–S and E–W less than 250 meters apart. On the morning of 17 October, ROV "Kaikō" dive #272 began and recovered over 33 hours later, with the ROV working at the bottom of the western basin for 26 hours (vicinity of 11°20.148' N, 142°11.774 E at ). Five "Kaikō" dives followed on a daily basis into the same area to service benthic landers and other scientific equipment, with dive #277 recovered on 25 October. Traps brought up large numbers of amphipods (sea fleas), and cameras recorded holothurians (sea cucumbers), White polychaetes (bristle worms), tube worms, and other biological species. During its 1998, 1999 surveys, "Kairei" was equipped with a GPS satellite-based radionavigation system. The United States government lifted the GPS selective availability in 2000, so during its 2002 survey, "Kairei" had access to non-degraded GPS positional services and achieved single digit meter accuracy in geodetic positioning.


title: Challenger Deep

text: The 2.516-ton research vessel "Melville", at the time operated by the Scripps Institution of Oceanography, took the Cook Expedition, Leg 6 with chief scientist Patricia Fryer of the University of Hawaii from Guam on 10 February 2001 to the Challenger Deep for a survey titled "Subduction Factory Studies in the Southern Mariana", including HMR-1 sonar mapping, magnetics, gravity measurements, and dredging in the Mariana arc region. They covered all three basins, then tracked lines of bathymetry East-West, stepping northward from the Challenger Deep in sidesteps, covering more than north into the backarc with overlapping swaths from their SeaBeam 2000 12 kHz multi-beam echosounder and MR1 towed system. They also gathered magnetic and gravity information, but no seismic data. Their primary survey instrument was the MR1 towed sonar, a shallow-towed 11/12 kHz bathymetric sidescan sonar developed and operated by the Hawaii Mapping Research Group (HMRG), a research and operational group within University of Hawaii's School of Ocean and Earth Science and Technology (SOEST) and the Hawaii Institute of Geophysics and Planetology (HIGP). The MR1 is full-ocean-depth capable, and provides both bathymetry and sidescan data.


title: Challenger Deep

text: Leg 7 of the Cook Expedition continued the MR-1 survey of the Mariana Trench backarc from 4 March to 12 April 2001 under chief scientist Sherman Bloomer of Oregon State University.


title: Challenger Deep

text: In May/June 2009 the US Navy-owned 3,064-ton twin-hulled research vessel "Kilo Moana" (T-AGOR 26) was sent to the Challenger Deep area to conduct research. "Kilo Moana" is civilian-manned and operated by SOEST. It is equipped with two multibeam echosounders with sub-bottom profiler add-ons (the 191-beam 12 kHz Kongsberg Simrad EM120 with SBP-1200, capable of accuracies of 0.2–0.5% of water depth across the entire swath), gravimeter, and magnetometer. The EM-120 uses 1 by 1 degree sonar-emissions at the sea surface. Each 1 degree beam width sonar ping expands to cover a circular area about in diameter at depth. Whilst mapping the Challenger Deep the sonar equipment indicated a maximum depth of at an undisclosed position.<ref name="Daily Reports for R/V KILO MOANA"></ref><ref name="Scientic Equipment aboard the R/V KILO MOANA"></ref> Navigation equipment includes the Applanix POS MV320 V4, rated at accuracies of 0.5–2 m. RV "Kilo Moana" was also used as the support ship of the hybrid remotely operated underwater vehicle (HROV) "Nereus" that dove three times to the Challenger Deep bottom during the May/June 2009 cruise and did not confirm the sonar established maximum depth by its support ship.


title: Challenger Deep

text: Cruise YK09-08 brought the JAMSTEC 4,429-ton research vessel "Yokosuka" back to the Mariana Trough and to the Challenger Deep June–July 2009. Their mission was a two-part program: surveying three hydrothermal vent sites in the southern Mariana Trough backarc basin near 12°57'N, 143°37'E about 130 nmi northeast of the central basin of the Challenger Deep, using the autonomous underwater vehicle "Urashima". AUV "Urashima" dives #90–94, were to a maximum depth of 3500 meters, and were successful in surveying all three sites with a Reson SEABAT7125AUV multibeam echosounder for bathymetry, and multiple water testers to detect and map trace elements spewed into the water from hydrothermal vents, white smokers, and hot spots. Kyoko OKINO from the Ocean Research Institute, University of Tokyo, was principal investigator for this aspect of the cruise.


title: Challenger Deep

text: The second goal of the cruise was to deploy a new "10K free fall camera system" called "Ashura", to sample sediments and biologics at the bottom of the Challenger Deep. The principal investigator at the Challenger Deep was Taishi Tsubouchi of JAMSTEC. The lander "Ashura" made two descents: on the first, 6 July 2009, "Ashura" bottomed at at . The second descent (on 10 July 2009) was to at . The 270 kg "Ashura" was equipped with multiple baited traps, a HTDV video camera, and devices to recover sediment, water, and biological samples (mostly amphipods at the bait, and bacteria and fungus from the sediment and water samples).


title: Challenger Deep

text: On 7 October 2010, further sonar mapping of the Challenger Deep area was conducted by the US Center for Coastal & Ocean Mapping/Joint Hydrographic Center (CCOM/JHC) aboard the 4.762-ton "Sumner". The results were reported in December 2011 at the annual American Geophysical Union fall meeting. Using a Kongsberg Maritime EM 122 multi-beam echosounder system coupled to positioning equipment that can determine latitude and longitude up to accuracy, from thousands of individual soundings around the deepest part the CCOM/JHC team preliminary determined that the Challenger Deep has a maximum depth of at , with an estimated vertical uncertainty of ± at two standard deviations (i.e. ≈ 95.4%) confidence level. A secondary deep with a depth of was located at approximately to the east at in the eastern basin of the Challenger Deep.


title: Challenger Deep

text: JAMSTEC returned "Yokosuka" to the Challenger Deep with cruise YK10-16, 21–28 November 2010. The chief scientist of this joint Japanese-Danish expedition was Hiroshi Kitazato of the Institute of Biogeosciences, JAMSTEC. The cruise was titled "Biogeosciences at the Challenger Deep: relict organisms and their relations to biogeochemical cycles". The Japanese teams made five deployments of their 11,000-meter camera system (three to 6,000 meters – two into the central basin of the Challenger Deep) which returned with 15 sediment cores, video records and 140 scavenging amphipod specimens. The Danish Ultra Deep Lander System was employed by Ronnie Glud et al on four casts, two into the central basin of the Challenger Deep and two to 6,000 m some 34 nmi west of the central basin. The deepest depth recorded was on 28 November 2010 – camera cast CS5 – }, at a corrected depth of (the central basin).


title: Challenger Deep

text: With JAMSTEC Cruises YK13-09 and YK13-12, "Yokosuka" hosted chief scientist Hidetaka Nomaki for a trip to New Zealand waters (YK13-09), with the return cruise identified as YK13-12. The project name was QUELLE2013; and the cruise title was: "In situ experimental & sampling study to understand abyssal biodiversity and biogeochemical cycles". They spent one day on the return trip at the Challenger Deep to obtain DNA/RNA on the large amphipods inhabiting the Deep ("Hirondellea gigas"). Hideki Kobayashi (Biogeos, JAMSTEC) and team deployed a benthic lander on 23 November 2013 with eleven baited traps (three bald, five covered by insulating materials, and three automatically sealed after nine hours) into the central basin of the Challenger Deep at , depth . After an eight-hour, 46-minute stay at the bottom, they recovered some 90 individual "Hirondellea gigas".


title: Challenger Deep

text: JAMSTEC deployed "Kairei" to the Challenger Deep again 11–17 January 2014, under the leadership of chief scientist Takuro Nunora. The cruise identifier was KR14-01, titled: "Trench biosphere expedition for the Challenger Deep, Mariana Trench". The expedition sampled at six stations transecting the central basin, with only two deployments of the "11-K camera system" lander for sediment cores and water samples to "Station C" at the deepest depth, i.e. , at . The other stations were investigated with the "Multi-core" lander, both to the backarc northward, and to the Pacific Plate southward. The 11,000-meter capable crawler-driven ROV "ABIMSO" was sent to 7,646 m depth about 20 nmi due north of the central basin (ABISMO dive #21) specifically to identify possible hydrothermal activity on the north slope of the Challenger Deep, as suggested by findings from "Kairei" cruise KR08-05 in 2008. "AMISMO" dives #20 and #22 were to 7,900 meters about 15 nmi north of the deepest waters of the central basin. Italian researchers under the leadership of Laura Carugati from the Polytechnic University of Marche, Italy (UNIVPM) were investigating the dynamics in virus/prokaryotes interactions in the Mariana Trench.


title: Challenger Deep

text: From 16–19 December 2014, the Schmidt Ocean Institute's 2,024-ton research vessel "Falkor", under chief scientist Douglas Bartlett from the Scripps Institution of Oceanography, deployed four different untethered instruments into the Challenger Deep for seven total releases. Four landers were deployed on 16 December into the central basin: the baited video-equipped lander "Leggo" for biologics; the lander "ARI" to for water chemistry; and the probes "Deep Sound 3" and "Deep Sound 2". Both Deep Sound probes recorded acoustics floating at depth, until "Deep Sound 3" imploded at the depth of (about above the bottom) at . The "Deep Sound 2" recorded the implosion of "Deep Sound 3", providing a unique recording of an implosion within the Challenger Deep depression. In addition to the loss of the "Deep Sound 3" by implosion, the lander "ARI" failed to respond upon receiving its instruction to drop weights, and was never recovered. On 16/17 December, "Leggo" was returned to the central basin baited for amphipods. On the 17th, RV "Falkor" relocated 17 nms eastward to the eastern basin, where they again deployed both the "Leggo" (baited and with its full camera load), and the "Deep Sound 2". "Deep Sound 2" was programmed to drop to and remain at that depth during its recording of sounds within the trench. On 19 December "Leggo" landed at at a uncorrected depth of according to its pressure sensor readings. This reading was corrected to depth. "Leggo" returned with good photography of amphipods feeding on the lander’s mackerel bait and with sample amphipods. "Falknor" departed the Challenger Deep on 19 December en route the Marianas Trench Marine National Monument to the Sirena Deep. RV "Falkor" had both a Kongsberg EM302 and EM710 multibeam echosounder for bathymetry, and an Oceaneering C-Nav 3050 global navigation satellite system receiver, capable of calculating geodetic positioning with an accuracy better than horizontally and vertically.


title: Challenger Deep

text: From 10 to 13 July 2015, the Guam-based 1,930-ton US Coast Guard Cutter "Sequoia" (WLB 215) hosted a team of researchers, under chief scientist Robert P. Dziak, from the NOAA Pacific Marine Environmental Laboratory (PMEL), the University of Washington, and Oregon State University, in deploying PMEL's "Full-Ocean Depth Mooring", a 45-meter-long moored deep-ocean hydrophone and pressure sensor array into the western basin of the Challenger Deep. A 6-hour descent into the western basin anchored the array at of water depth, at , about 1 km northeast of "Sumner" deepest depth, recorded in 2010. After 16 weeks, the moored array was recovered on 2–4 November 2015. "Observed sound sources included earthquake signals (T phases), baleen and odontocete cetacean vocalizations, ship propeller sounds, airguns, active sonar and the passing of a Category 4 typhoon." The science team described their results as "the first multiday, broadband record of ambient sound at Challenger Deep, as well as only the fifth direct depth measurement".


title: Challenger Deep

text: The 3,536-ton research vessel "Xiangyanghong 09" deployed on Leg II of the 37th China Cruise Dayang (DY37II) sponsored by the National Deep Sea Center, Qingdao and the Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences (Sanya, Hainan), to the Challenger Deep western basin area (11°22' N, 142°25' E) 4 June – 12 July 2016. As the mother ship for China’s manned deep submersible "Jiaolong", the expedition carried out an exploration of the Challenger Deep to investigate the geological, biological, and chemical characteristics of the hadal zone. The diving area for this leg was on the southern slope of the Challenger Deep, at depths from about . The submersible completed nine manned dives on the northern backarc and south area (Pacific plate) of the Challenger Deep to depths from . During the cruise, "Jiaolong" regularly deployed gas-tight samplers to collect water near the sea bottom. In a test of navigational proficiency, "Jiaolong" used an Ultra-Short Base Line (USBL) positioning system at a depth more than to retrieve sampling bottles.


title: Challenger Deep

text: From 22 June to 12 August 2016 (cruises 2016S1 and 2016S2), the Chinese Academy of Sciences' 6,250-ton submersible support ship "Tansuo 1" (meaning: to explore) on her maiden voyage deployed to the Challenger Deep from her home port of Sanya, Hainan Island. On 12 July 2016, the ROV "Haidou-1" dived to a depth of in the Challenger Deep area. They also cast a free-drop lander, rated free-drop ocean-floor seismic instruments (deployed to ), obtained sediment core samples, and collected over 2000 biological samples from depth ranging from . The "Tansuo 01" operated along the 142°30.00' longitude line, about 30 nmi east of the earlier DY37II cruise survey (see "Xiangyanghong 09" above).


title: Challenger Deep

text: In November 2016 sonar mapping of the Challenger Deep area was conducted by the Royal Netherlands Institute for Sea Research (NIOZ)/GEOMAR Helmholtz Centre for Ocean Research Kiel aboard the 8,554-ton Deep Ocean Research Vessel "Sonne". The results were reported in 2017. Using a Kongsberg Maritime EM 122 multi-beam echosounder system coupled to positioning equipment that can determine latitude and longitude the team determined that the Challenger Deep has a maximum depth of at (), with an estimated vertical uncertainty of ± at one standard deviation (≈ 68.3%) confidence level. The analysis of the sonar survey offered a grid resolution at bottom depth, so small dips in the bottom that are less than that size would be difficult to detect from the 0.5 by 1 degree sonar-emissions at the sea surface. Each 0.5-degree beam width sonar ping expands to cover a circular area about in diameter at depth. The horizontal position of the grid point has an uncertainty of ±, depending on along-track or across-track direction. This depth () and position (about to the northeast) measurements differ significantly from the deepest point determined by the Gardner et al. (2014) study. The observed depth discrepancy with the 2010 sonar mapping and Gardner et al 2014 study are related to the application of differing sound velocity profiles, which are essential for accurate depth determination. "Sonne" used CTD casts about 1.6 km west of the deepest sounding to near the bottom of the Challenger Deep that were used for sound velocity profile calibration and optimization. Likewise the impact of using different projections, datum and ellipsoids during data acquisition can cause positional discrepancies between surveys.


title: Challenger Deep

text: In December 2016, the CAS 3,300-ton research vessel "Shiyan 3" deployed 33 broadband seismometers onto both the backarc northwest of the Challenger Deep, and onto the near southern Pacific Plate to the southeast, at depths of up to . This cruise was part of a $12 million Chinese-U.S. initiative, led by co-leader Jian Lin of the Woods Hole Oceanographic Institution; a 5-year effort (2017–2021) to image in fine detail the rock layers in and around the Challenger Deep.


title: Challenger Deep

text: The newly launched 4,800-ton research vessel (and mothership for the "Rainbow Fish" series of deep submersibles), the "Zhang Jian" departed Shanghai on 3 December. Their cruise was to test three new deep-sea landers, one unmanned search submersible and the new "Rainbow Fish" 11,000-meter manned deep submersible, all capable of diving to 10,000 meters. From 25 to 27 December, three deep-sea landing devices descended into the trench. The first Rainbow Fish lander took photographs, the second took sediment samples, and the third took biological samples. All three landers reached over 10,000 meters, and the third device brought back 103 amphipods. Cui Weicheng, director of Hadal Life Science Research Center at Shanghai Ocean University, led the team of scientists to carry out research at the Challenger Deep in the Mariana Trench. The ship is part of China’s national marine research fleet but is owned by a Shanghai marine technology company.


title: Challenger Deep

text: CAS' Institute of Deep-sea Science and Engineering sponsored "Tansuo-1" return to the Challenger Deep 20 January – 5 February 2017 (cruise TS03) with baited traps for capture of fish and other macrobiology near the Challenger and Sirena Deeps. On 29 January they recovered photography and samples of a new species of snailfish from the Northern slope of the Challenger Deep at , newly designated "Pseudoliparis swirei". They also placed four or more CTD casts into the "central" and "eastern" basins of the Challenger Deep, as part of the World Ocean Circulation Experiment (WOCE).


title: Challenger Deep

text: Tokyo University of Marine Science and Technology dispatched the research vessel "Shinyo Maru" to the Mariana Trench from 20 January to 5 February 2017 with baited traps for capture of fish and other macrobiology near the Challenger and Sirena Deeps. On 29 January they recovered photography and samples of a new species of snailfish from the Northern slope of the Challenger Deep at , which has been newly designated "Pseudoliparis swirei".


title: Challenger Deep

text: Water samples were collected at the Challenger Deep from 11 layers of the Mariana Trench in March 2017. Seawater samples from 4 to 4,000 m were collected by Niskin bottles mounted to a Seabird SBE25 CTDs; whereas water samples at depths from 6,050 m to 8,320 m were collected by a self-designed acoustic-controlled full ocean depth water samplers. In this study, scientists studied the RNA of pico- and nano-plankton from the surface to the hadal zone.


title: Challenger Deep

text: JAMSTEC deployed "Kairei" to the Challenger Deep in May 2017 for the express purpose of testing the new full-ocean depth ROV "UROV11K" (Underwater ROV 11,000-meter-capable), as cruise KR 17-08C, under chief scientist Takashi Murashima. The cruise title was: "Sea trial of a full depth ROV "UROV11K" system in the Mariana Trench". "UROV11K" carried a new 4K High Definition video camera system, and new sensors to monitor the hydrogen-sulfide, methane, oxygen, and hydrogen content of the water. Unfortunately, on "UROV11K" ascent from (at about 11°22.30’N 142°35.8 E, in the "eastern" basin) on 14 May 2017, the ROV's buoyancy failed at depth, and all efforts to retrieve the ROV were unsuccessful. The rate of descent and drift is not available, but the ROV bottomed to the east of the deepest waters of the eastern basin as revealed by the ship's maneuvering on 14 May. Murashima then directed the Kairei to a location about 35 nmi east of the eastern basin of the Challenger Deep to test a new "Compact Hadal Lander" which made three descents to depths from 7,498 to 8,178 m for testing the Sony 4K camera and for photography of fish and other macro-biologics.


title: Challenger Deep

text: On its maiden voyage, the 2,150-ton twin-hulled scientific research vessel "Shen Kuo" (also "Shengkuo", "Shen Ko", or "Shen Quo"), departed Shanghai on 25 November 2018 and returned 8 January 2019. They operated in the Mariana Trench area, and on 13 December tested a system of underwater navigation at a depth exceeding 10,000 metres, during a field trial of the "Tsaihungyuy" (ultra-short baseline) system. Project leader Tsui Veichen stated that, with the tsaihungyuy equipment at depth, it was possible to obtain a signal and determine exact geolocations. The research team from Shanghai Ocean University and Westlake University was led by Cui Weicheng, director of Shanghai Ocean University’s Hadal Science and Technology Research Center (HSRC).


title: Challenger Deep

text: The equipment to be tested included a manned submersible (not full ocean depth – depth achieved not available) and two deep-sea landers, all capable of diving to depths of 10,000 meters, as well as a ROV that can go to 4,500 meters. They took photographs and obtained samples from the trench, including water, sediment, macro-organisms and micro-organisms. Cui says, "If we can take photos of fish more than 8,145 meters under water, ... we will break the current world record. We will test our new equipment including the landing devices. They are second generation. The first generation could only take samples in one spot per dive, but this new second generation can take samples at different depths in one dive. We also tested the ultra short baseline acoustic positioning system on the manned submersible, the future of underwater navigation."


title: Challenger Deep

text: In November 2019, as cruise SR1916, a NIOZ team led by chief scientist Hans van Haren, with Scripps technicians, deployed to the Challenger Deep aboard the 2,641-ton research vessel , to recover a mooring line from the western basin of the Challenger Deep. The long mooring line in the Challenger Deep consisted of top-floatation positioned around depth, two sections of Dyneema neutrally buoyant line, two Benthos acoustic releases and two sections of self-contained instrumentation to measure and store current, salinity and temperature. Around the depth position two current meters were mounted below a long array of 100 high-resolution temperature sensors. In the lower position starting above the sea floor 295 specially designed high-resolution temperature sensors were mounted, the lowest of which was above the trench floor. The mooring line was deployed and left by the NIOZ team during the November 2016 RV "Sonne" expedition with the intention to be recovered in late 2018 by "Sonne". The acoustic commanded release mechanism near the bottom of the Challenger Deep failed at the 2018 attempt. RV "Sally Ride" was made available exclusively for a final attempt to retrieve the mooring line before the release mechanism batteries expired. "Sally Ride" arrived at the Challenger Deep on 2 November. This time a 'deep release unit' lowered by one of "Sally Ride" winch-cables to around 1,000 m depth pinged release commands and managed to contact the near-bottom releases. After being nearly three years submerged, mechanical problems had occurred in 15 of the 395 temperature sensors. The first results indicate the occurrence of internal waves in the Challenger Deep.


title: Challenger Deep

text: Since May 2000, with the help of non-degraded signal satellite navigation, civilian surface vessels equipped with professional dual-frequency capable satellite navigation equipment can measure and establish their geodetic position with an accuracy in the order of meters to tens of meters whilst the western, central and eastern basins are kilometers apart.


title: Challenger Deep

text: In 2014, a study was conducted regarding the determination of the depth and location of the Challenger Deep based on data collected previous to and during the 2010 sonar mapping of the Mariana Trench with a Kongsberg Maritime EM 122 multibeam echosounder system aboard USNS "Sumner". This study by James. V. Gardner et al. of the Center for Coastal & Ocean Mapping-Joint Hydrographic Center (CCOM/JHC), Chase Ocean Engineering Laboratory of the University of New Hampshire splits the measurement attempt history into three main groups: early single-beam echo sounders (1950s–1970s), early multibeam echo sounders (1980s – 21st century), and modern (i.e., post-GPS, high-resolution) multibeam echo sounders. Taking uncertainties in depth measurements and position estimation into account the raw data of the 2010 bathymetry of the Challenger Deep vicinity consisting of 2,051,371 soundings from eight survey lines was analyzed. The study concludes that with the best of 2010 multibeam echosounder technologies after the analysis a depth uncertainty of ± (95% confidence level) on 9 degrees of freedom and a positional uncertainty of ± (2drms) remain and the location of the deepest depth recorded in the 2010 mapping is at . The depth measurement uncertainty is a composite of measured uncertainties in the spatial variations in sound-speed through the water volume, the ray-tracing and bottom-detection algorithms of the multibeam system, the accuracies and calibration of the motion sensor and navigation systems, estimates of spherical spreading, attenuation throughout the water volume, and so forth.


title: Challenger Deep

text: Both the RV "Sonne" expedition in 2016, and the RV "Sally Ride" expedition in 2019 expressed strong reservations concerning the depth corrections applied by the Gardner et al. study of 2014, and serious doubt concerning the accuracy of the deepest depth calculated by Gardner (in the "western" basin), of after analysis of their multibeam data on a grid. Dr. Hans van Haren, chief scientist on the RV "Sally Ride" cruise SR1916, indicated that Gardner's calculations were too deep due to the "sound velocity profiling by Gardner et al. (2014)."


title: Challenger Deep

text: In 2018-2019, the deepest points of each ocean were mapped using a full‐ocean depth Kongsberg EM 124 multibeam echosounder aboard "DSSV Pressure Drop". In 2021, a data paper was published by Cassandra Bongiovanni, Heather A. Stewart and Alan J. Jamieson regarding the gathered data donated to GEBCO. The deepest depth recorded in the 2019 Challenger Deep sonar mapping was ± at in the eastern basin. This depth closely agrees with the deepest point ( ±) determined by the Van Haren et al. sonar bathymetry. The geodetic position of the deepest depth according to the Van Haren et al. significantly differs (about to the west) with the 2021 paper. After post-processing the initial depth estimates by application of a full-ocean depth sound velocity profile Bongiovanni et al. report an (almost) as deep point at in the western basin that geodetically differs about with the deepest point position determined by Van Haren et al. ( in the western basin). After analysis of their multibeam data on a grid, the Bongiovanni et al. 2021 paper states the technological accuracy does not currently exist on low-frequency ship-mounted sonars required to determine which location was truly the deepest, nor does it currently exist on deep-sea pressure sensors.


title: Challenger Deep

text: In 2021, a study by Samuel F. Greenaway, Kathryn D. Sullivan, Samuel H. Umfress, Alice B. Beittel and Karl D. Wagner was published presenting a revised estimate of the maximum depth of the Challenger Deep based on a series of submersible dives conducted in June 2020. These depth estimates are derived from acoustic echo sounding profiles referenced to in-situ direct pressure measurements and corrected for observed oceanographic properties of the water-column, atmospheric pressure, gravity and gravity-gradient anomalies, and water-level effects. The study concludes according to their calculations the deepest observed seafloor depth was ± below mean sea level at a 95% condidence level at in the eastern basin. For this estimate, the error term is dominated by the uncertainty of the employed pressure sensor, but Greenaway et al. show that the gravity correction is also substantial. The Greenaway et al. study compares its results with other recent acoustic and pressure-based measurements for the Challenger Deep and concludes the deepest depth in the western basin is very nearly as deep as the eastern basin. The disagreement between the maximum depth estimates and their geodetic positions between post-2000 published depths however exceed the accompanying margins of uncertainty, raising questions regarding the measurements or the reported uncertainties.


title: Challenger Deep

text: Another 2021 paper by Scott Loranger, David Barclay and Michael Buckingham, besides a December 2014 implosion shock wave based depth estimate of , which is among the deepest estimated depths, also treatises the differences between various maximum depth estimates and their geodetic positions.


title: Challenger Deep

text:
The 2010 maximal sonar mapping depths reported by Gardner et.al. in 2014 and Greenaway et al. study in 2021 have not been confirmed by direct descent (pressure gauge/manometer) measurements at full-ocean depth.
Expeditions have reported direct measured maximal depths in a narrow range.


title: Challenger Deep

text: For the "western" basin deepest depths were reported as by in 1960 and ± by "DSV Limiting Factor" in June 2020.<br>


title: Challenger Deep

text: For the "eastern" basin deepest depths were reported as by ROV in 1995, by ROV "Nereus" in 2009, by in 2012, by benthic lander "Leggo" in May 2019, and ± by "DSV Limiting Factor" in May 2019.


title: Challenger Deep

text: On 23 January 1960, the Swiss-designed "Trieste", originally built in Italy and acquired by the U.S. Navy, supported by the USS "Wandank" (ATF 204) and escorted by the USS "Lewis" (DE 535), descended to the ocean floor in the trench manned by Jacques Piccard (who co-designed the submersible along with his father, Auguste Piccard) and USN Lieutenant Don Walsh. Their crew compartment was inside a spherical pressure vessel – measuring 2.16 metres in diameter suspended beneath a buoyancy tank 18.4 metres in length – which was a heavy-duty replacement (of the Italian original) built by Krupp Steel Works of Essen, Germany. The steel walls were 12.7 cm thick and designed to withstand pressure of up to .


title: Challenger Deep

text: Their descent took almost five hours and the two men spent barely twenty minutes on the ocean floor before undertaking the three-hour-and-fifteen-minute ascent. Their early departure from the ocean floor was due to their concern over a crack in the outer window caused by the temperature differences during their descent.


title: Challenger Deep

text: "Trieste" dove at/near , bottoming at ± into the Challenger Deep's "western" basin, as measured by an onboard manometer. Another source states the measured depth at the bottom was measured with a manometer at ±.


title: Challenger Deep

text: Navigation of the support ships was by celestial and LORAN-C with an accuracy of or less. Fisher noted that the "Trieste"'s reported depth "agrees well with the sonic sounding."


title: Challenger Deep

text: On 26 March 2012 (local time), Canadian film director James Cameron made a solo manned descent in the DSV "Deepsea Challenger" to the bottom of the Challenger Deep.


title: Challenger Deep

text: At 07:52 ChST (21:52 UTC), "Deepsea Challenger" arrived at the bottom. The descent lasted 2 hours and 36 minutes and the recorded depth was when "Deepsea Challenger" touched down.


title: Challenger Deep

text: Cameron had planned to spend about six hours near the ocean floor exploring but decided to start the ascent to the surface after only 2 hours and 34 minutes. The time on the bottom was shortened because a hydraulic fluid leak in the lines controlling the manipulator arm obscured the visibility out the only viewing port. It also caused the loss of the submersible's starboard thrusters. At around 12:00 ChST (02:00 UTC on 26 March), the Deepsea Challenger website says the sub resurfaced after a 90-minute ascent, although Paul Allen's tweets indicate the ascent took only about 67 minutes. During a post-dive press conference Cameron said: "I landed on a very soft, almost gelatinous flat plain. Once I got my bearings, I drove across it for quite a distance ... and finally worked my way up the slope." The whole time, Cameron said, he didn't see any fish, or any living creatures more than an inch (2.54 cm) long: "The only free swimmers I saw were small amphipods" – shrimplike bottom-feeders.


title: Challenger Deep

text: 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 ±.


title: Challenger Deep

text: Caladan Oceanic's "Ring of Fire" expedition in the Pacific included six crewed descents and twenty-five lander deployments into all three basins of the Challenger Deep all piloted by Victor Vescovo and further topographical and marine life survey of the entire Challenger Deep. The expedition craft used are the Deep Submersible Support Vessel DSSV "Pressure Drop", Deep-Submergence Vehicle DSV "Limiting Factor" and the ultra-deep-sea landers "Closp", "Flere" and "Skaff".


title: Challenger Deep

text: During the first crewed dive on 7 June 2020 Victor Vescovo and former US astronaut (and former NOAA Administrator) Kathryn D. Sullivan descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle "Limiting Factor".


title: Challenger Deep

text: On 12 June 2020 Victor Vescovo and mountaineer and explorer Vanessa O'Brien descended to the "Eastern Pool" of the Challenger Deep spending three hours mapping the bottom. O’Brien said her dive scanned about a mile of desolate bottom terrain, finding that the surface is not flat, as once was thought, but sloping, and by about , subject to verification, of course.


title: Challenger Deep

text: On 14 June 2020 Victor Vescovo and John Rost descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle "Limiting Factor" spending four hours at depth and transiting the bottom for nearly 2 miles.


title: Challenger Deep

text: On 20 June 2020 Victor Vescovo and Kelly Walsh descended to the "Western Pool" of the Challenger Deep in the Deep-Submergence Vehicle "Limiting Factor" spending four hours at the bottom. They reached a maximum depth of . Kelly Walsh is the son of the "Trieste’s" captain Don Walsh who descended there in 1960 with Jacques Piccard.


title: Challenger Deep

text: On 21 June 2020 Victor Vescovo and Woods Hole Oceanographic Institution researcher Ying-Tsong Lin descended to the "Central Pool" of the Challenger Deep in the Deep-Submergence Vehicle "Limiting Factor". They reached a maximum depth of ±.


title: Challenger Deep

text: On 26 June 2020 Victor Vescovo and Jim Wigginton descended to the "Eastern Pool" of the Challenger Deep in the Deep-Submergence Vehicle "Limiting Factor".


title: Challenger Deep

text: "Fendouzhe" (奋斗者, "Striver") is a crewed Chinese deep-sea submersible developed by the China Ship Scientific Research Center (CSSRC). Between 10 October and 28 November 28, 2020, it carried out thirteen dives in the Mariana Trench as part of a test programme. Of these, eight led to depths of more than . On 10 November 2020, the bottom of the Challenger Deep was reached by "Fendouzhe" with three Chinese scientists (Zhāng Wěi 张伟 [pilot], Zhào Yáng 赵洋, and Wáng Zhìqiáng 王治强) onboard whilst livestreaming the descent to a reported depth of . This makes the " Fendouzhe " the fourth crewed submersible vehicle achieving a successful descent. The pressure hull of "Fendouzhe", made from a newly developed titanium alloy, offers space for three people in addition to technical equipment. "Fendouzhe" is equipped with cameras made by the Norwegian manufacturer Imenco.


title: Challenger Deep

text: According to Ye Cong, the chief designer of the submersible, China's goals for the dive aren't just scientific investigation but also the future use of deep sea seabed resources.


title: Challenger Deep

text: On 28 February 2021 Caladan Oceanic's "Ring of Fire 2" expedition arrived over the Challenger Deep and conducted crewed descents and lander deployments into the Challenger Deep. At the start the (unmanned) ultra-deep-sea lander "Skaff" was deployed to collect water column data by CTD for the expedition. The effects of the Pacific subducting plate crashing into the Philippine Plate was amongst the things researched onsite.


title: Challenger Deep

text: On 1 March 2021 the first crewed descent to the eastern pool was made by Victor Vescovo and Richard Garriott. Garriott became the 17th person to descend to the bottom.


title: Challenger Deep

text: On 5 March a descent to the eastern pool was made by Victor Vescovo and Hamish Harding. They traversed the bottom of Challenger Deep.


title: Challenger Deep

text: On 11 March 2021 a descent to the western pool was made by Victor Vescovo and marine botanist Nicole Yamase.


title: Challenger Deep

text: On 13 April 2021 a descent was made by deep water submersible operations expert Rob McCallum and Tim Macdonald who piloted the dive.


title: Challenger Deep

text: In July 2022 for the fourth consecutive year, Caladan Oceanic's deep submergence system, consisting of the deep submersible DSV "Limiting Factor" supported by the mother ship DSSV "Pressure Drop", returned to the Challenger Deep for dives into the Challenger Deep.


title: Challenger Deep

text: In early July, 2022 Victor Vescovo was joined by Aaron Newman as mission specialist for a dive into the Central pool. On July 5, 2022 Tim Macdonald as pilot and Jim Kitchen as mission specialist for a dive into the Eastern pool. On July 8, 2022 Victor Vescovo was joined by Dylan Taylor as mission specialist for a dive into the Eastern pool.


title: Challenger Deep

text: Victor Vescovo (for his 15th dive into the Challenger Deep) was joined by geographer and oceanographer Dawn Wright as mission specialist on the July 12, 2022 dive to in the Western pool. Wright operated the world's first sidescan sonar to ever operate at full-ocean depth to capture detailed imagery along short transects of the southern wall of the Western pool.


title: Challenger Deep

text: The remotely operated vehicle (ROV) "Kaikō" made many unmanned descents to the Mariana Trench from its support ship RV "Yokosuka" during two expeditions in 1996 and 1998.


title: Challenger Deep

text: From 29 February to 4 March the ROV "Kaiko" made three dives into the "central" basin, "Kaiko" #21 – "Kaiko" #23, . Depths ranged from at , to at ; dives #22 & #23 to the north, and dive #21 northeast of the deepest waters of the "central" basin. During the 1996 measurements the temperature (water temperature increases at great depth due to adiabatic compression), salinity and water pressure at the sampling station was , 34.7‰ and , respectively at depth. 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 . The manometer measured depth of ± at for the Challenger Deep is believed to be the most accurate measurement taken up to then.


title: Challenger Deep

text: The ROV "Kaiko" was the first vehicle to visit to the bottom of the Challenger Deep since the bathyscaph "Trieste"'s dive in 1960, and the first success in sampling the trench bottom sediment/mud, from which "Kaiko" obtained over 360 samples. Approximately 3,000 different microbes were identified in the samples.


title: Challenger Deep

text: From 2 May to 5 June 2009, the RV "Kilo Moana" hosted the Woods Hole Oceanographic Institution (WHOI) hybrid remotely operated vehicle (HROV) "Nereus" team for the first operational test of the "" in its 3-ton tethered ROV mode. The "Nereus" team was headed by the Expedition Leader Andy Bowen of WHOI, Dr. Louis Whitcomb of Johns Hopkins University, and Dr. Dana Yoerger, also of WHOI. The expedition had co-chief scientists: biologist Dr. Tim Shank of WHOI, and geologist Dr. Patricia Fryer of the University of Hawaii, to head the science team exploiting the ship’s bathymetry and organizing the science experiments deployed by the "Nereus". From "Nereus" dive #007ROV to just south of Guam, to dive #010ROV into the Nero Deep at , the testing gradually increased depths and complexities of activities at the bottom.


title: Challenger Deep

text: Dive #011ROV, on 31 May 2009, saw the "Nereus" piloted on a 27.8-hour underwater mission, with about ten hours transversing the "eastern" basin of the Challenger Deep – from the south wall, northwest to the north wall – streaming live video and data back to its mothership. A maximum depth of was registered at . The "" then relocated to the "western" basin, where a 19.3-hour underwater dive found a maximum depth of on dive #012ROV, and on dive #014ROV in the same area (11°19.59 N, 142°12.99 E) encountered a maximum depth of . The "Nereus" was successful in recovering both sediment and rock samples from the "eastern" and the "western" basins with its manipulator arm for further scientific analysis. The HROV’s final dive was about to the north of the Challenger Deep, in the backarc, where they dove at the TOTO Caldera (12°42.00 N, 143°31.5 E). 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.<ref name="Daily Reports for R/V KILO MOANA April and May 2009"></ref>


title: Challenger Deep

text: The HROV "Nereus" was lost on 10 May 2014 while conducting a dive at in depth in the Kermadec Trench.


title: Challenger Deep

text: In June 2008, the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) deployed the research vessel "Kairei" to the area of Guam for cruise KR08-05 Leg 1 and Leg 2.


title: Challenger Deep

text: On 1–3 June 2008, during Leg 1, the Japanese robotic deep-sea probe "ABISMO" (Automatic Bottom Inspection and Sampling Mobile) on dives 11–13 almost reached the bottom about east of the Challenger Deep: "Unfortunately, we were unable to dive to the sea floor because the legacy primary cable of the Kaiko system was a little bit short. The 2-m long gravity core sampler was dropped in free fall, and sediment samples of 1.6m length were obtained. Twelve bottles of water samples were also obtained at various depths..." ABISMO's dive #14 was into the TOTO caldera (12°42.7777 N, 143°32.4055 E), about 60 nmi northeast of the deepest waters of the "central" basin of the Challenger Deep, where they obtained videos of the hydrothermal plume. Upon successful testing to , JAMSTEC' ROV "ABISMO" became, briefly, the only full-ocean-depth rated ROV in existence. On 31 May 2009, the ABISMO was joined by the Woods Hole Oceanographic Institution's HROV "Nereus" as the only two operational full ocean depth capable remotely operated vehicles in existence. During the ROV "ABISMO's" deepest sea trails dive its manometer measured a depth of ± in "Area 1" (vicinity of 12°43' N, 143°33' E).


title: Challenger Deep

text: Leg 2, under chief scientist Takashi Murashima, operated at the Challenger Deep 8–9 June 2008, testing JAMSTEC’s new full ocean depth "Free Fall Mooring System," i.e. a lander. The lander was successfully tested twice to depth, taking video images and sediment samplings at , in the "central" basin of the Challenger Deep.


title: Challenger Deep

text: On 23 May 2016, the Chinese submersible "Haidou-1" dove to a depth of at an undisclosed position in the Mariana Trench, making China the third country after Japan (ROV "Kaikō"), and the US (HROV "Nereus"), to deploy a full-ocean-depth ROV. This autonomous and remotely operated vehicle has a design depth of .


title: Challenger Deep

text: On 8 May 2020, the Russian submersible "Vityaz-D" dove to a depth of at an undisclosed position in the Mariana Trench.


title: Challenger Deep

text: The summary report of the expedition lists radiolaria from the two dredged samples taken when the Challenger Deep was first discovered. These ("Nassellaria" and "Spumellaria") were reported in the Report on Radiolaria (1887) written by Ernst Haeckel.


title: Challenger Deep

text: On their 1960 descent, the crew of the "Trieste" noted that the floor consisted of diatomaceous ooze and reported observing "some type of flatfish" lying on the seabed.


title: Challenger Deep

text: Many marine biologists are now skeptical of this supposed sighting, and it is suggested that the creature may instead have been a sea cucumber. The video camera on board the "Kaiko" probe spotted a sea cucumber, a scale worm and a shrimp at the bottom. At the bottom of the Challenger deep, the "Nereus" probe spotted one polychaete worm (a multi-legged predator) about an inch long.


title: Challenger Deep

text: An analysis of the sediment samples collected by "Kaiko" found large numbers of simple organisms at . While similar lifeforms have been known to exist in shallower ocean trenches (> 7,000 m) and on the abyssal plain, the lifeforms discovered in the Challenger Deep possibly represent taxa distinct from those in shallower ecosystems.


title: Challenger Deep

text: Most of the organisms collected were simple, soft-shelled foraminifera (432 species according to National Geographic), with four of the others representing species of the complex, multi-chambered genera "Leptohalysis" and "Reophax". Eighty-five percent of the specimens were organic, soft-shelled allogromiids, which is unusual compared to samples of sediment-dwelling organisms from other deep-sea environments, where the percentage of organic-walled foraminifera ranges from 5% to 20%. As small organisms with hard, calcareous shells have trouble growing at extreme depths because of the high solubility of calcium carbonate in the pressurized water, scientists theorize that the preponderance of soft-shelled organisms in the Challenger Deep may have resulted from the typical biosphere present when the Challenger Deep was shallower than it is now. Over the course of six to nine million years, as the Challenger Deep grew to its present depth, many of the species present in the sediment died out or were unable to adapt to the increasing water pressure and changing environment.


title: Challenger Deep

text: On 17 March 2013, researchers reported data that suggested piezophilic microorganisms thrive in the Challenger Deep. Other researchers reported related studies that microbes thrive inside rocks up to below the sea floor under of ocean off the coast of the northwestern United States. According to one of the researchers, "You can find microbes everywherethey're extremely adaptable to conditions, and survive wherever they are."


title: One-party state

text: A one-party state, single-party state, one-party system, or single-party system is a type of sovereign state in which only one political party has the right to form the government, usually based on the existing constitution. All other parties are either outlawed or allowed to take only a limited and controlled participation in elections. Sometimes the term ""de facto" one-party state" is used to describe a dominant-party system that, unlike the one-party state, allows (at least nominally) democratic multiparty elections, but the existing practices or balance of political power effectively prevent the opposition from winning power.


title: One-party state

text: Although it is predated by the 1714 to 1783 "age of the Whig oligarchy" in Great Britain, the rule of the Committee of Union and Progress (CUP) over the Ottoman Empire following the 1913 coup d'etat is often considered the first one-party state.


title: One-party state

text: One-party states justify themselves through various methods. Most often, proponents of a one-party state argue that the existence of separate parties runs counter to national unity. Others argue that the one party is the vanguard of the people, being its most politically aware members, and therefore the party's right to rule cannot be legitimately questioned. The Soviet government argued that the existence of multiple political parties would perpetuate class struggle, so only a single party could lead a classless proletariat; it therefore made the Communist Party of the Soviet Union the only authorised political party.


title: One-party state

text: Some one-party states only outlaw opposition parties, while allowing allied parties to exist as part of a permanent coalition (such as a popular front). However, these allied parties are largely or completely subservient to the ruling party and must accept the ruling party's monopoly of power as a condition of their existence. Examples of this are the People's Republic of China under the United Front, the National Front in former East Germany and the Democratic Front for the Reunification of Korea in North Korea. Other states outlaw all other parties yet allow non-party members to run for legislative seats as independents, as was the case with Taiwan's Tangwai movement in the 1970s and 1980s, as well as the elections in the former Soviet Union. Still others have only a single legal party, membership of which is a prerequisite for holding public office, such as in Turkmenistan under the rule of Saparmurat Niyazov or Zaire under Mobutu Sese Seko.


title: One-party state

text: Within their own countries, dominant parties ruling over one-party states are often referred to simply as "the Party". For example, in reference to the Soviet Union, "the Party" meant the Communist Party of the Soviet Union; in reference to the pre-1991 Republic of Zambia, it referred to the United National Independence Party.