The AN/FPS-20 was a widely used L band early warning and ground-controlled interception radar system employed by the United States Air Force Air Defense Command , the NORAD Pinetree Line in Canada , the USAF CONAD in the continental United States, and a variety of other users. The design started life as the Bendix AN/FPS-3 in 1950, was upgraded to the FPS-20, then spawned over a dozen different variants as additional upgrades were applied. The FPS-20 formed the backbone of the US air defense network through the early Cold War with over 200 units deployed. Most FPS-20 sites were replaced by modern equipment in the late 1960s, although a number were turned over to the FAA , modified for air traffic control use, and became ARSR-60s .
52-606: The first AN/FPS-3 arrived in December 1950, slated for installation at Eniwetok Atoll to control aircraft involved in the atomic bomb tests of early 1951. Over the next few years, 48 FPS-3s were installed to replace older systems in the Lashup Radar Network . The FPS-3 and was also produced as the AN/MPS-7 , a mobile version. The system used two 5J26 magnetrons at 750 kW peak power, operating at 1300 MHz
104-408: A 400 Hz pulse repetition frequency (prf) and 2 microsecond pulse width. The antenna was driven at three fixed speeds of 3.3, 5 or 10 RPM, normally operating at 5. Many of the operating modules were mounted on the rotating platform, with the output signals fed via slip rings to amplifiers and displays at the base of the unit. The FPS-3 was limited to about 55,000 feet (17 km) altitude, which
156-463: A US$ 150 million trust fund. The fund was intended to generate US$ 18 million a year, which would be payable to claimants on an agreed-upon schedule. If the US$ 18 million a year generated by the fund was not enough to cover claims, the principal of the fund could be used. A Marshall Islands Nuclear Claims Tribunal was established to adjudicate claims. In 2000, the tribunal made a compensation award to
208-555: A concrete dome (the Runit Dome) was built on Runit Island to deposit radioactive soil and debris. The Runit Dome is deteriorating and could be breached by a typhoon, though the sediments in the lagoon are even more radioactive than those which are contained. The U.S. government referred to the atoll as "Eniwetok" until 1974, when it changed its official spelling to "Enewetak" (along with many other Marshall Islands place names , to more properly reflect their pronunciation by
260-539: A lake is hu ( 湖 ), and a lagoon is xihu ( 潟湖 ). In the French Mediterranean several lagoons are called étang ("lake"). Contrariwise, several other languages have specific words for such bodies of water. In Spanish, coastal lagoons generically are laguna costera , but those on the Mediterranean coast are specifically called albufera . In Russian and Ukrainian, those on
312-422: A regular flow of fresh water an "estuary". Davis does state that the terms "lagoon" and "estuary" are "often loosely applied, even in scientific literature". Timothy M. Kusky characterizes lagoons as normally being elongated parallel to the coast, while estuaries are usually drowned river valleys, elongated perpendicular to the coast. Coastal lagoons are classified as inland bodies of water. When used within
364-893: A similar digital MTI system, the AN/FPS-113 . Under the Joint Electronics Type Designation System (JETDS), all U.S. military radar and tracking systems are assigned a unique identifying alphanumeric designation. The letters “AN” (for Army-Navy) are placed ahead of a three-letter code. Thus, the AN/FPS-20 represents the 20th design of an Army-Navy “Fixed, Radar, Search” electronic device. Eniwetok Atoll Enewetak Atoll ( / ɛ ˈ n iː w ə ˌ t ɔː k , ˌ ɛ n ɪ ˈ w iː t ɔː k / ; also spelled Eniwetok Atoll or sometimes Eniewetok ; Marshallese : Ānewetak , [ænʲeːwɛːdˠɑk] , or Āne-wātak , [ænʲeːwæːdˠɑk] ; known to
416-521: Is a shallow body of water separated from a larger body of water by a narrow landform , such as reefs , barrier islands , barrier peninsulas, or isthmuses . Lagoons are commonly divided into coastal lagoons (or barrier lagoons ) and atoll lagoons . They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries . Lagoons are common coastal features around many parts of
468-458: Is actually the third-largest lake by area in the country. The brackish water lagoon may be thus explicitly identified as a "coastal lagoon" ( laguna costera ). In Portuguese, a similar usage is found: lagoa may be a body of shallow seawater, or a small freshwater lake not linked to the sea. Lagoon is derived from the Italian laguna , which refers to the waters around Venice ,
520-738: Is the second-westernmost atoll of the Ralik Chain and is 305 kilometers (190 mi) west from Bikini Atoll . It was held by the Japanese from 1914 until its capture by the United States in February 1944 during World War II , then became Naval Base Eniwetok . Nuclear testing by the US totaling the equivalent of over 30 megatons of TNT took place during the Cold War ; in 1977–1980,
572-636: The AN/FPS-91 and 91A. The similar MK-748 applied to the -60 series resulted in the AN/FPS-64A , AN/FPS-65A , AN/FPS-66A and AN/FPS-67A . Canadian AN/FPS-87s were also converted, becoming AN/FPS-93 and 93A. These units were used with the SAGE system. The FPS-20 was widely used in Japan. They produced their own series of modifications, including a tunnel diode based amplifier and a separate receiver for
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#1732790744393624-626: The Black Sea are liman ( лиман ), while the generic word is laguna ( Лагуна ). Similarly, in the Baltic , Danish has the specific Nor [ da ] , and German the specifics Bodden and Haff , as well as generic terms derived from laguna . In Poland these lagoons are called zalew ("bay"), in Lithuania marios ("lagoon, reservoir"). In Jutland several lagoons are known as fjord . In New Zealand
676-490: The Marshall Islanders ). Enewetak Atoll formed atop a seamount . The seamount was formed in the late Cretaceous . This seamount is now about 1,400 meters (4,600 ft) below sea level. It is made of basalt , and its depth is due to a general subsidence of the entire region and not because of erosion . Enewetak has a mean elevation above sea level of 3 meters (9.8 ft). Humans have inhabited
728-523: The Māori word hapua refers to a coastal lagoon formed at the mouth of a braided river where there are mixed sand and gravel beaches, while waituna , an ephemeral coastal waterbody, is neither a true lagoon, lake nor estuary. Some languages differentiate between coastal and atoll lagoons. In French, lagon [ fr ] refers specifically to an atoll lagoon, while coastal lagoons are described as étang [ fr ] ,
780-610: The Venetian Lagoon . Laguna is attested in English by at least 1612, and had been Anglicized to "lagune" by 1673. In 1697 William Dampier referred to a "Lagune or Lake of Salt water" on the coast of Mexico. Captain James Cook described an island "of Oval form with a Lagoon in the middle" in 1769. Atoll lagoons form as coral reefs grow upwards while the islands that the reefs surround subside, until eventually only
832-458: The Wadden Sea , have strong tidal currents and mixing. Coastal lagoons tend to accumulate sediments from inflowing rivers, from runoff from the shores of the lagoon, and from sediment carried into the lagoon through inlets by the tide. Large quantities of sediment may be occasionally be deposited in a lagoon when storm waves overwash barrier islands. Mangroves and marsh plants can facilitate
884-399: The radioactive cloud to test onboard samples. B-17 mother ships controlled the drones while flying within visual distance of them. In all, 16 to 20 B-17s took part in this operation, of which half were controlling aircraft and half were drones. To examine the explosion clouds of the nuclear bombs in 1957/58, several rockets (mostly from rockoons ) were launched. One USAF airman Jimmy Robinson
936-559: The 110th Naval Construction Battalion arrived on February 21 and 27 to begin construction of Stickell Field. It had two taxiways and a 6,800-by-400-foot (2,070 by 120 m) runway. In June 1945, the 67th CB arrived to build a 35,000 man recreation center to be turned over to CBMU 608. In 1950, John C. Woods , who executed the Nazi war criminals convicted at the Nuremberg Trials , was accidentally electrocuted there. After
988-638: The 110th Naval Construction Battalion expanded the base, building a coral-surfaced parking area and shops for minor aircraft and engine overhaul. A marine ways was installed on a Japanese pier and boat-repair shops were also erected. US Navy and Marine units based at Parry Island included: From 1958 through 1960 the United States installed the Missile Impact Location System (MILS) in the Navy managed Pacific Missile Range, later
1040-518: The AN/FPS-20B. The slotted-waveguide antenna pictured above the AN/FPS-20 is for the associated IFF system. The FPS-20s were simple pulse-radar systems and subject to jamming using basic techniques. This led to a second series of upgrades to provide anti-jamming capabilities starting in 1959. Among these were the GPA-102 (MK-448) which turned an FPS-20 into an FPS-64 and a FPS-20A to an FPS-66, and
1092-539: The Air Force managed Western Range , to localize the splash downs of test missile nose cones. MILS was developed and installed by the same entities that had completed the first phase of the Atlantic and U.S. West Coast SOSUS systems. A MILS installation, consisting of both a target array for precision location and a broad ocean area system for good positions outside the target area, was installed at Eniwetok as part of
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#17327907443931144-721: The Airborne Instruments Laboratories system, producing the AN/FPS-20/20A JAPAN, or -J. The Indian Air Force used the FPS-20 with a new digital moving target indicator (MTI) system from Bendix to create the AN/FPS-100 and 100A. These systems were known as the "Blue Pearl", or Bendix Radar Processor BRP-150. These were remanufactured units with a new antenna, and included a new low-noise front-end amplifier. General Dynamics later produced
1196-750: The GPA-103 (MK-447) which turned a FPS-20 into an FPS-65 and the FPS-20A into an FPS-67. Similar upgrades using a Canadian OA-4831 system produced the AN/FPS-87 and AN/FPS-87A. The BADGE 412-L upgrade of the FPS-20A created the AN/FPS-82 . A more major update was the MK-747, which added a new antenna from Raytheon, the Diplex Gating Unit (DGU), a bandpass filter and other modifications, to produce
1248-651: The Japanese as Brown Atoll or Brown Island ; Japanese : ブラウン環礁 ) is a large coral atoll of 40 islands in the Pacific Ocean and with its 296 people (as of 2021) forms a legislative district of the Ralik Chain of the Marshall Islands . With a land area total less than 5.85 square kilometers (2.26 sq mi), it is no higher than 5 meters (16.4 ft) and surrounds a deep central lagoon , 80 kilometers (50 mi) in circumference . It
1300-554: The U.S. exhumed the bodies of United States servicemen killed in the Battle of Enewetak and returned them to the United States to be re-buried by their families. 43 nuclear tests were fired at Enewetak from 1948 to 1958. The first hydrogen bomb test, code-named Ivy Mike , occurred in late 1952 as part of Operation Ivy ; it vaporized the islet of Elugelab , It also created two new elements : Fermium and Einsteinium . This test included B-17 Flying Fortress drones to fly through
1352-399: The anchorage at Enewetok became a major US Naval Advance Base with Service Squadron 4 and Service Squadron 10 stationed in the lagoon. The daily average of ships present during the first half of July 1944 was 488; during the second half of July, the daily average number of ships at Enewetak was 283. Naval Base Eniwetok was part of the vast Naval Base Marshall Islands . US Navy Seabees of
1404-463: The atoll since about 1,000 B.C. The islands were first settled by Austronesian islanders. The first European colonizers to Enewetak, Spanish explorer Álvaro de Saavedra Cerón , arrived on 10 October 1529. He called the island " Los Jardines " (The Gardens). In 1794, sailors aboard the British merchant sloop Walpole called the islands "Brown's Range" (thus, the Japanese name "Brown Atoll"). It
1456-613: The cleanup project was US$ 239 million. The United States government declared the southern and western islands in the atoll safe for habitation in 1980, and residents of Enewetak returned that same year. The military members who participated in that cleanup mission are suffering from many health issues, but the U.S. Government refused to provide health coverage until 2022 with the passage of the Honoring our PACT Act . The 2000 environmental restoration award included funds for additional cleanup of radioactivity on Enewetak. Rather than scrape
1508-413: The community. Men from the 110th Naval Construction Battalion arrived on Eniwetok between 21 and 27 February 1944 and began clearing the island for construction of a bomber airfield. A 2,100-meter (6,900 ft) by 120-meter (390 ft) runway with taxiways and supporting facilities was built. The first plane landed on 11 March. By 5 April the first operational bombing mission was conducted. The base
1560-626: The context of a distinctive portion of coral reef ecosystems, the term "lagoon" is synonymous with the term "back reef" or "backreef", which is more commonly used by coral reef scientists to refer to the same area. Many lagoons do not include "lagoon" in their common names. Currituck , Albemarle and Pamlico Sounds in North Carolina , Great South Bay between Long Island and the barrier beaches of Fire Island in New York , Isle of Wight Bay , which separates Ocean City, Maryland from
1612-481: The dome, causing radioactive material to leak out. Section 177 of the 1983 Compact of Free Association between the governments of the United States and the Marshall Islands establishes a process for Marshallese to make a claim against the United States government as a result of damage and injury caused by nuclear testing. That same year, an agreement was signed to implement Section 177, which established
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1664-735: The east, no aviation personnel were stationed there and the island had only token defenses. When the Gilberts fell to the United States, the Imperial Japanese Army assigned defense of the atoll to the 1st Amphibious Brigade , formed from the 3rd Independent Garrison, which had previously been stationed in Manchukuo . The 1st Amphibious Brigade arrived on January 4, 1944. Some 2,586 of its 3,940 men were left to defend Eniwetok Atoll, supplemented by aviation personnel, civilian employees, and laborers. However, they were unable to finish
1716-670: The end of 2008 and May 2010. Due to stock market losses, payments rates that have outstripped fund income, and other issues, the fund was nearly exhausted, as of May 2010, and unable to make any additional awards or payments. A lawsuit by Marshallese arguing that "changed circumstances" made Nuclear Claims Tribunal unable to make just compensation was dismissed by the Supreme Court of the United States in April 2010. Marshall Islands Public School System operates Enewetak Elementary School. Marshall Islands High School on Majuro serves
1768-605: The end of World War II, Enewetak came under the control of the United States as part of the Trust Territory of the Pacific Islands , until the independence of the Marshall Islands in 1986. During its tenure, the United States evacuated the local residents many times, often involuntarily. The atoll was used for nuclear testing , as part of the Pacific Proving Grounds . Before testing commenced,
1820-534: The fortifications before the American attack came in February. During the ensuing Battle of Eniwetok , the Americans captured Enewetak in a five-day amphibious operation. Fighting mainly took place on Engebi Islet, site of the most important Japanese installation, although some combat occurred on the main islet of Enewetak itself and on Parry Island, where there was a Japanese seaplane base. Following its capture,
1872-597: The generic word for a still lake or pond. In Vietnamese, Đầm san hô refers to an atoll lagoon, whilst Đầm phá is coastal. In Latin America, the term laguna in Spanish, which lagoon translates to, may be used for a small fresh water lake in a similar way a creek is considered a small river. However, sometimes it is popularly used to describe a full-sized lake , such as Laguna Catemaco in Mexico, which
1924-466: The islands with Portland cement and buried it in an atomic blast crater on the northern end of the atoll's Runit Island . The material was placed in the 9.1-meter (30 ft) deep, 110-meter (360 ft) wide crater created by the May 5, 1958, " Cactus " nuclear weapons test. A dome composed of 358 concrete panels, each 46 centimeters (18 in) thick, was constructed over the material. The final cost of
1976-630: The lagoon. Lagoons with little or no interchange with the open ocean, little or no inflow of fresh water, and high evaporation rates, such as Lake St. Lucia , in South Africa , may become highly saline. Lagoons with no connection to the open ocean and significant inflow of fresh water, such as the Lake Worth Lagoon in Florida in the middle of the 19th century, may be entirely fresh. On the other hand, lagoons with many wide inlets, such as
2028-556: The land along the coast). Coastal lagoons do not form along steep or rocky coasts, or if the range of tides is more than 4 metres (13 ft). Due to the gentle slope of the coast, coastal lagoons are shallow. A relative drop in sea level may leave a lagoon largely dry, while a rise in sea level may let the sea breach or destroy barrier islands, and leave reefs too deep underwater to protect the lagoon. Coastal lagoons are young and dynamic, and may be short-lived in geological terms. Coastal lagoons are common, occurring along nearly 15 percent of
2080-444: The people of Enewetak consisting of US$ 107.8 million for environmental restoration; US$ 244 million in damages to cover economic losses caused by loss of access and use of the atoll; and US$ 34 million for hardship and suffering. In addition, as of the end of 2008, another US$ 96.658 million in individual damage awards were made. Only US$ 73.526 million of the individual claims award has been paid, however, and no new awards were made between
2132-696: The potassium decontamination project was US$ 103.3 million. A report by the US Congressional Research Service projects that the majority of the atoll will be fit for human habitation by 2026–2027, after nuclear decay, de-contamination and environmental remediation efforts create sufficient dose reductions. However, in November 2017, the Australian Broadcasting Corporation reported that rising sea levels caused by climate change are seeping inside
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2184-407: The reefs remain above sea level. Unlike the lagoons that form shoreward of fringing reefs, atoll lagoons often contain some deep (>20 m (66 ft)) portions. Coastal lagoons form along gently sloping coasts where barrier islands or reefs can develop offshore, and the sea-level is rising relative to the land along the shore (either because of an intrinsic rise in sea-level, or subsidence of
2236-627: The rest of Worcester County, Maryland , Banana River in Florida , US, Lake Illawarra in New South Wales , Australia, Montrose Basin in Scotland , and Broad Water in Wales have all been classified as lagoons, despite their names. In England, The Fleet at Chesil Beach has also been described as a lagoon. In some languages the word for a lagoon is simply a type of lake: In Chinese
2288-402: The start of World War II. The atoll, together with other parts of Marshall Islands located to the west of 164°E, was placed under the governance of Pohnpei district during the Japanese administration period, separately from the rest of the Marshall Islands. In November 1942, the Japanese built an airfield on Engebi Island. As they used it only for refueling planes between Truk and islands to
2340-587: The system supporting Intercontinental Ballistic Missile (ICBM) tests. Other Pacific MILS shore terminals were at the Marine Corps Air Station Kaneohe Bay supporting Intermediate Range Ballistic Missile (IRBM) tests with impact areas northeast of Hawaii and the other ICBM test support systems at Midway Island and Wake Island . [REDACTED] This article incorporates public domain material from the Air Force Historical Research Agency Lagoon A lagoon
2392-428: The topsoil off, replace it with clean topsoil, and create another radioactive waste repository dome at some site on the atoll (a project estimated to cost US$ 947 million), most areas still contaminated on Enewetak were treated with potassium . Soil that could not be effectively treated for human use was removed and used as fill for a causeway connecting the two main islands of the atoll (Enewetak and Parry). The cost of
2444-459: The world's shorelines. In the United States, lagoons are found along more than 75 percent of the Eastern and Gulf Coasts . Coastal lagoons can be classified as leaky, restricted, or choked. Coastal lagoons are usually connected to the open ocean by inlets between barrier islands. The number and size of the inlets, precipitation, evaporation, and inflow of fresh water all affect the nature of
2496-582: The world. Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal , coral reef , or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity . The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restricts "lagoon" to bodies of water with little or no fresh water inflow, and little or no tidal flow, and calls any bay that receives
2548-417: Was later named for Lieutenant John H. Stickell . In mid-September 1944 operations at Wrigley Airfield on Engebi Island were transferred to Eniwetok. US Navy and Marine units based at Eniwetok included: The airstrip is now abandoned and its surface partially covered by sand. The Imperial Japanese Navy had developed a seaplane base on Parry Island. Following its capture on 22 February, Seabee's from
2600-493: Was lost at sea during the tests. Robinson's F-84 Thunderjet crashed and sank 3.5 miles (5.6 km) short of the island. Robinson's body was never recovered. A radiological survey of Enewetak was conducted from 1972 to 1973. In 1977, the United States military began decontamination of Enewetak and other islands. During the three-year, US$ 100 million cleanup process, the military mixed more than 80,000 cubic meters (100,000 cu yd) of contaminated soil and debris from
2652-517: Was seen as a limitation in light of new jet-powered bombers known to be in development in the USSR. This led to the development of the AN/GPA-27 add-on unit, increasing the altitude to 65,000 feet (20 km). Installations began in 1956. New-build units from Bendix with this equipment pre-installed became the AN/FPS-20 in 1957. Otherwise similar units with an antenna from General Electric were known as
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#17327907443932704-799: Was visited by about a dozen ships before the establishment of the German colony of the Marshall Islands in 1885. With the rest of the Marshalls, Enewetak was captured by the Imperial Japanese Navy in 1914, during World War I and mandated to the Empire of Japan by the League of Nations in 1920. The Japanese administered the island under the South Seas Mandate , but mostly left affairs in hands of traditional local leaders until
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