Ascension Island
Constituent part of Saint Helena, Ascension and Tristan da Cunha
Flag Coat of arms
Anthem: "God Save the King"
Topographic map of Ascension Island
Location of Ascension Island in the southern Atlantic Ocean
Sovereign state	United Kingdom
British settlement	1815
Dependency of Saint Helena	12 September 1922
Current constitution	1 September 2009
Capital and largest settlement	Georgetown 7°56′S 14°25′W / 7.933°S 14.417°W / -7.933; -14.417
Official languages	English
Government	Devolved locally governing dependency under a constitutional monarchy
• Monarch	Charles III
• Governor	Nigel Phillips
• Administrator	Simon Minshull[1]
Legislature	Island Council
Government of the United Kingdom
• Minister	David Rutley[2]
Area
• Total	88 km2 (34 sq mi)
Highest elevation	859 m (2,818 ft)
Population
• 2016 census	806[3]
• Density	9.15/km2 (23.7/sq mi)
Currency	Saint Helena pound (£) (SHP)
Time zone	UTC±00:00 (GMT)
Date format	dd/mm/yyyy
Driving side	left
Calling code	+247
UK postcode	ASCN 1ZZ
ISO 3166 code	SH-AC
Internet TLD	.ac

Ascension Island is an isolated volcanic island, 7°56′ south of the Equator in the South Atlantic Ocean. It is about 1,000 miles (1,600 km) from the coast of Africa and 1,400 miles (2,300 km) from the coast of South America. It is governed as part of the British Overseas Territory of Saint Helena, Ascension and Tristan da Cunha,^[4] of which the main island, Saint Helena, is around 800 miles (1,300 km) to the southeast. The territory also includes the sparsely populated Tristan da Cunha archipelago, 2,300 miles (3,700 km) to the south, about halfway to the Antarctic Circle.

Ascension Island was discovered by the Portuguese navigator João da Nova in 1501 and named Conception Island, but was rediscovered in 1503 on Ascension Day by Alphonse de Albuquerque and renamed.^[5] Ascension Island was garrisoned by the British Admiralty from 22 October 1815 to 1922 and was an important refueling stop for ships and commercial airliners in the days of international air travel by flying boats. During World War II, it was an important naval and air station, especially providing antisubmarine warfare bases in the Battle of the Atlantic.^[6]

The island is the location of RAF Ascension Island, which is a Royal Air Force station, a European Space Agency rocket tracking station, a British-American signals intelligence facility and the BBC World Service Atlantic Relay Station. The island was used extensively as a staging point by the British military during the Falklands War. Ascension Island hosts one of four ground antennas that assist in the operation of the Global Positioning System (GPS) navigational system (the others are on Kwajalein Island, Diego Garcia, and Cape Canaveral). NASA operates a Meter Class Autonomous Telescope (MCAT) on Ascension Island for tracking orbital debris, which is potentially hazardous to operating spacecraft and astronauts, at a facility called the John Africano NASA/AFRL Orbital Debris Observatory.^[7]

History

Discovery

The island's discovery is disputed. An undocumented claim states that it was discovered in 1501, either on 25 March or 21 May, by João da Nova, on his outward voyage to India. It is claimed that he named it Ilha de Nossa Señora de Conceiçao ("The Island of Our Lady of the Conception") or "Conception Island". However, there is no documentary evidence of his discovery. It was discovered or re-discovered in 1503 on the Ascension Day (which fell on Thursday, 21 May 1503, of that year) , (11 may 1503 julian calendar ) by Alphonse de Albuquerque and named (or renamed) Ilha da Ascensão after this feast day. This discovery was documented by Albuquerque.^[8][9]

Dry and barren, the island had little appeal for passing ships except for collecting fresh meat, and was not claimed for the Portuguese Crown. Mariners could hunt for the numerous seabirds and the enormous female green turtles that laid their eggs on the sandy beaches. The Portuguese also introduced goats as a potential source of meat for future mariners.

In February 1701, HMS Roebuck, commanded by William Dampier, sank in the common anchoring spot in Clarence Bay to the northwest of the island. Sixty men survived for two months until they were rescued. Almost certainly, after a few days they found the strong water spring in the high interior of the island, in what is now called Breakneck Valley (there is a much smaller water source, lower on the mountain, which was named Dampier's Drip by people who probably misinterpreted Dampier's story).^[10]

It is possible, but disputed, that the island was sometimes used^[11] as an open prison for criminal mariners, although there is only one documented case of such an exile, a Dutch ship's officer, Leendert Hasenbosch, set ashore at Clarence Bay as a punishment for sodomy in May 1725.^[12] British mariners found the Dutchman's tent, belongings and diary in January 1726; the man's remains were not found. His diary was published in translation in London later that same year, under the title Sodomy Punish'd.^[13]

Organised settlement

Organised settlement of Ascension Island began in 1815, when the British garrisoned it as a precaution after imprisoning Napoleon on Saint Helena to the southeast.^{[citation needed]} On 22 October the Cruizer-class brig-sloops Zenobia and Peruvian claimed the island for King George III. The Royal Navy designated the island as a stone frigate, HMS Ascension, with the classification of "Sloop of War of the smaller class".^[14]

The location of the island made it a useful stopping-point for ships and communications. The Royal Navy used the island as a victualling station for ships, particularly those of the West Africa Squadron working against the slave trade.^[15] A garrison of Royal Marines was based at Ascension from 1823 and Colonel Edward Nicolls became the first commandant.^[16]

Botany

In 1836 the second Beagle voyage visited Ascension. Charles Darwin described it as an arid, treeless island, with nothing growing near the coast. Sparse vegetation inland supported "about six hundred sheep, many goats, a few cows & horses," large numbers of guineafowl imported from the Cape Verde islands, rats, mice, and land crabs; he agreed with the saying attributed to the people of St Helena that "We know we live on a rock, but the poor people at Ascension live on a cinder." He noted the care taken to sustain "houses, gardens & fields placed near the summit of the central mountain," and cisterns at roadsides to provide drinking water. The springs were carefully managed, "so that a single drop of water may not be lost: indeed the whole island may be compared to a huge ship kept in first-rate order." In commenting on this, he noted René Primevère Lesson's remark "that the English nation alone would have thought of making the island of Ascension a productive spot; any other people would have held it as a mere fortress in the ocean."^[17]

In 1843, botanist and explorer Joseph Hooker visited the island. Four years later, Hooker, with much encouragement from Darwin, advised the Royal Navy that with the help of Kew Gardens, they should institute a long-term plan of shipping trees to Ascension. The planted trees would capture more rain and improve the soil, allowing the barren island to become a garden. So, from 1850 and years thereafter, ships came with an assortment of plants from botanical gardens in Argentina, Europe and South Africa. By the late 1870s Norfolk pines, eucalyptus, bamboo, and banana trees grew in profusion at the highest point of the island, Green Mountain, creating a tropical cloud forest.^[18]

Astronomical observation

Beginning in July 1877, the astronomer Sir David Gill and his wife Isobel spent six months on Ascension Island. This was to take advantage of the near approach of Mars occurring that year. Based on Johannes Kepler's laws of planetary motion, Gill conceived that in pioneering the use of a heliometer, he would be able to accurately measure the position of Mars while in opposition on his own, rather than in combination with many observers simultaneously recording the position of the planet as had been the technique during the time.^[19] This is because a heliometer is a telescope that uses a split image to measure the angular separation of celestial bodies. In observing this from near the equator, a greater observable distance would be visible, hence a temporary observatory being decided upon for Ascension.^[20]

Although originally based in Georgetown, the pair found the evenings to be too cloudy to make observations of the night sky due to Georgetown being located downwind of orographic cloud emanating from Green Mountain.^[20] Isobel quickly endeavoured to find an area less affected by the evening cloud and trekked several miles over lava fields to find a new location. Having found an area on the southwest of the island seemingly less affected, they then had to determine how to move 20 tons of delicate observational equipment to the new location. Fortunately, a small, clear beach was located nearby which was used for landing the equipment by sea. This was later named Mars Bay, a name which it carries to this day and which has since been designated a Nature Reserve.^[21] The couple then spent several months camped out at the bay making their observations, assisted by a Kru sailor (known at the time as a krooman) and a marine.

All of the effort was ultimately a success, producing a solar distance of 93.08 ± 0.16 million miles, which is a range from 92.92 – 93.24, since shown to be (just) correct by the modern measurement of 92.9558. As a result of his work on the solar parallax, David Gill went on to be appointed Royal Astronomer at the Cape of Good Hope.^[22]

End of Admiralty rule and early government

Between 1872 and 1889, the population of the island was listed as HMS Flora (Tender), under the orders of the Commander-in-Chief, Cape of Good Hope, estimated to number just 150 in 1888.^[23] HMS Flora had been the guardship at Ascension from 1865 to 1872 before being ordered south to become the Simonstown depot ship. Five ratings died while on a recreational boat trip in 1879.^[24]

In 1899, as part of the British effort in the Second Boer War, the Eastern Telegraph Company (later Cable & Wireless plc) installed the first submarine communications cable from the island, connecting the UK with its colonies in South Africa.^[25][26] In 1922, letters patent made Ascension a dependency of Saint Helena, with control being officially handed over to the Eastern Telegraph Company from the Admiralty on 20 October 1922.^[27] The island was managed by the head of the Eastern Telegraph Company on the island until 1964 when the British Government appointed an Administrator to represent the Governor of Saint Helena in Ascension.^[25][26]

World War II

The Island was under direct control of the Board of Admiralty until 1922.^[28]

During World War II, to supply and augment extensive amphibious aircraft antisubmarine patrol operations ongoing from the early days of the war, the United States built an airbase on Ascension Island, known as "Wideawake",^[29] after a nearby colony of sooty terns (locally called 'wideawake' birds because of their loud, distinctive constant (day-and-night) cawing chatter).^[30] The airbase, which was under construction by the 38th Combat Engineer Battalion of the Army Corps of Engineers, was unexpectedly visited by two British Fairey Swordfish torpedo planes on 15 June 1942.^{[citation needed]} According to one of the pilots, Peter Jinks, the planes were fired upon before being recognised as allies. The Swordfish had to land on the unfinished airstrip, thus becoming the first aircraft to land on Ascension Island proper, which had long served as an anti-submarine warfare base for Consolidated PBY Catalina flying boats. The event was commemorated with a postage stamp 15 June 1982.

The airfield was used by the US military as a stopping point for American aircraft crossing the Atlantic Ocean on the way to theatres of operation in Europe and Africa. American bombers based at Wideawake were engaged in the Laconia incident.

The only local military action during World War II occurred on 9 December 1941. At around mid-day, the German submarine U-124 approached Georgetown on the surface with the intention of sinking any ships at anchor or shelling the cable station.^{[citation needed]} Fort Bedford, a two-gun shore battery at Cross Hill, above Georgetown, fired on the submarine. The guns scored no hits but the U-boat submerged and retreated. The battery remains largely intact, together with its guns, BL 5.5 inch Mark I naval guns removed from HMS Hood during a refit in Malta in 1938.

The airbase fell into disuse following the American departure at the end of World War II.

Later military involvement

With the Space Race and the Cold War, the Americans returned in 1956.^{[citation needed]} Wideawake Airfield expanded in the mid-1960s. The runway was extended, widened, and improved to allow its use by large aircraft, and later to act as an emergency runway for the Space Shuttle, although the Shuttle never had to use it.^[29] At the time, it was the world's longest airport runway.^[30] The United States Space Force uses the island as part of its Eastern Range.^[31] NASA established a tracking station on the island in 1967, which it operated for more than 20 years before closing it down in 1990.^[29]

Ascension was the shore terminal for the furthest down range installation of the Atlantic Missile Impact Location System (MILS), an acoustic system for locating splashdown of test nose cones.^[32] The MILS hydrophones that were located in the SOFAR channel for broad area coverage have played a significant role in long range acoustic transmission studies and incidents. The island's location makes it a first point of Atlantic reception for acoustics from the other oceans. As an example the Ascension hydrophones received and the site processed signals generated near Heard Island in the Indian Ocean some 9,200 km (5,700 mi; 5,000 nmi) from the Ascension arrays and passing around Africa.^[33][34] The Ascension array was one of those involved in the Vela incident acoustic signal in which there were correlated acoustic arrivals with the time and estimated location of the double flash detected by the Vela satellite.^[35]

A joint Government Communications Headquarters and National Security Agency signals intercept station was also established on Ascension during the Cold War.^[36][37] The island retains a role in space exploration: the European Space Agency now operates an Ariane monitoring facility there.^[29] The BBC Atlantic Relay Station was installed in 1966 for short-wave broadcasts to Africa and South America and because of the BBC's considerable resources, eventually BBC External Services began sourcing requirements generally for the Island through BBC Engineering Purchasing Department based in 4 Cavendish Square, London; items were requisitioned and ordered from suppliers, delivered to export packers, Evan Cook and shipped to Ascension on RMS St. Helena.

In 1982, the British task force used Ascension Island as a staging post during the Falklands War. After strengthening and improving the structure, the Royal Air Force deployed a fleet of Avro Vulcan bombers and Handley Page Victor tankers at the airfield. Vulcans launched the opening shots of the British offensive from Ascension in Operation Black Buck. The RAF also used the base to supply the task force. Because of the increase in air traffic during the war, Wideawake, with up to 400 movements of all types each day, was one of the busiest airfields in the world for a short period.^[38] The Royal Navy's fleet stopped at Ascension for refuelling on the way. Following the war, the British retained an increased presence on the island, establishing RAF Ascension Island, and providing a refuelling stop for the regular airlink between RAF Brize Norton in Oxfordshire, and RAF Mount Pleasant in the Falkland Islands.

Twenty-first century

As of 2004^[update], it was reported that the Composite Signals Organisation, an arm of GCHQ, continued to operate a signals interception facility at Cat Hill on Ascension.^[39] As of 2007^[update] NASA continued to list Ascension Island as a "downrange site" used for range safety instrumentation.^[40] In particular, the Post-Detect Telemetry System used to acquire launch vehicle telemetry includes a station on Ascension.^[41]

In 2008, British diplomats at the United Nations Commission on the Limits of the Continental Shelf (UN CLCS), requested sovereignty over 200,000 km² (77,220 sq mi) of submarine territory around the island. This would enable exploration into possible new reserves of oil, gas and minerals, though none are thought to exist.^[42]

In 2009, The St Helena, Ascension and Tristan da Cunha Constitution Order 2009 elevated Ascension Island, and Tristan da Cunha to equal constituent parts of the territory alongside Saint Helena, with their own governments and established the position of Governor of Ascension. Per Section 143 of the Constitution Order 2009 the person appointed as Governor of Saint Helena is ex officio Governor of Ascension.^[43]

In 2016, the United States Department of Energy started operating a mobile climate research facility on the island. It is operated by the Atmospheric Radiation Measurement Climate Research Facility (ARM) near the South East Crater, south of the Green Mountain summit. The field campaign requires the mobile facility to be operational for about 17 months until October 2017.^[44]

The island hosts one of four dedicated ground antennas that assist in the operation of the Global Positioning System (GPS) navigation system along with those on Diego Garcia (British Indian Ocean Territory), Kwajalein (Marshall Islands), and Cape Canaveral, Florida.^[45] NASA and the Air Force Research Laboratory operate a Meter-Class Autonomous Telescope (MCAT) on Ascension as part of the deep space surveillance system for tracking orbital debris, which can be a hazard to spacecraft and astronauts.^[45][46]

In 2023, the United Kingdom government announced that it was considering a proposal to send migrants arriving in the UK by boat to Ascension Island, should the Supreme Court rule that the Rwanda asylum plan is illegal.^[47]

Geography

The main island has an area of approximately 88 square kilometres (34 sq mi). A volcanic peak rising from 100 kilometres (62 mi) west of the Mid-Atlantic Ridge, much of the island is a wasteland of lava flows and cinder cones; forty-four distinct dormant craters have been identified.^[15]

Geology

Ascension is a geologically young formation, the tip of an undersea volcano which rose above the waves only a million years ago. Although volcanic activity is mainly associated with the Mid-Atlantic Ridge plate boundary 80 km to the west, Ascension also displays some features which are commonly attributed to "hotspot" volcanism. Such volcanism is typically assumed to arise from a deep mantle thermal plume from the core-mantle boundary. Alternatively it may result from minor deformations of the oceanic crust that cause extension and permit magma to rise passively up from the asthenosphere. Ascension is considered active and could have erupted as recently as 500 years ago, but the exact eruption date is elusive.^[48] Due to the low rainfall and geologically recent eruptions, its soil consists mostly of clinker.^[30]

The island consists of a wide range of alkaline rocks atypical for oceanic islands, ranging from basalt through trachyandesite and trachyte to rhyolite.^[49][50]

Climate

Ascension has a hot desert climate (BWh, according to the Köppen climate classification). The temperatures at the coast average from 22.7 to 27.8 °C (72.9 to 82.0 °F), and about 5 to 6 °C (9 to 11 °F) cooler at the highest point. Rain showers may occur at any time during the year, but tend to be heavier between June and September. Although the island is in the tropical zone, average annual rainfall is very low. The cause of this might be the relatively low temperature of the ocean water, as the Benguela Current and South Equatorial Current flow northward west of Africa. These currents bring cooling effects around the eastern South Atlantic Ocean. Tropical cyclones also occur only rarely in the South Atlantic Ocean which might be caused by the same phenomenon, and by strong vertical wind shear.^[51][52][53]