discovered the island on
Ascension Day 1501.
Discovery Two Portuguese chronicles suggest that João da Nova leading the third armada to India discovered Ascension in 1501. Da Nova is variously said to have sailed from Lisbon on 1 March, 5 March, 11 March, 26–27 March or 10 April.
João de Barros wrote that passing eight degrees beyond the equator, towards the south, an island was found to which the name Concepcão was given whilst
Damião de Góis’ later chronicle described the sighting of an island south of the line which was named Conçeicam. Several references suggest the island was rediscovered and named Ascension by
Afonso de Albuquerque in 1503 on Ascension Day. It is possible, but disputed, that the island was sometimes used 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. 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''.
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. On 22 October, the s and 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". 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. A garrison of
Royal Marines was based at Ascension from 1823 and Colonel
Edward Nicolls became the first commandant.
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." 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.
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. 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. Although originally based in
Georgetown, David and Isobel found the evenings to be too cloudy to make observations of the night sky due to Georgetown being located downwind of
orographic clouds that formed nightly over Green Mountain. The couple then spent several months camped out at the bay making their observations, assisted by a
Kru sailor (at that time called a
krooman) and a
marine. All of the effort was ultimately a success, producing a solar distance of miles, which is a range from since shown to be (just) correct by the modern measurement of 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.
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. 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. 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. 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. 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. 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", after a nearby colony of
sooty terns (locally called 'wideawake' birds because of their loud, distinctive constant (day-and-night) cawing chatter). 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.
NASA established a tracking station on the island in 1967, which it operated for more than 20 years before closing it down in 1990. 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 from the Ascension arrays and passing around Africa. 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. A joint
Government Communications Headquarters and
National Security Agency signals intercept station was also established on Ascension during the Cold War. The island retains a role in space exploration: the
European Space Agency now operates an
Ariane monitoring facility there. 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 , it was reported that the
Composite Signals Organisation, an arm of
GCHQ, continued to operate a signals interception facility at
Cat Hill on Ascension. NASA continued to list Ascension Island as a "downrange site" used for range safety instrumentation. In particular, the Post-Detect Telemetry System used to acquire launch vehicle
telemetry includes a station on Ascension. In 2008, British diplomats at the United Nations Commission on the Limits of the Continental Shelf (UN CLCS), requested sovereignty over 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. 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. 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. 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. 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. Due to the disrepair, the runway was shut down in 2016 to non-mission related or emergency flights. The airfield was cobbled together over numerous efforts beginning in World War 2, including multiple extensions, the addition of turning blisters and fast exit taxi-ways, and mill and overlay repairs. Beginning in 2020, the airfield underwent a complete reconstruction effort which brought it up to modern standards to support both US and UK air force airframes. The runway itself is an engineered base composed of granite which was imported from Nova Scotia, Canada and sand from Georgia, United States, under strict fumigation and inspection control of the on-island conservation group. During the construction effort, all material was required to be purchased new to avoid the introduction of any non-native species which could impact the native flora and fauna. To avoid disruptions to island operations, the runway was completed in two phases, each half at approximately 5,000 linear feet. The construction team also updated the lighting system, drainage, airfield signs, and roads connecting the airfield to Georgetown and the US base. The runway was completed and reopened in 2023. 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 the
Rwanda asylum plan illegal. ==Geography==