Statute mile in the context of "Kilometer"

The kilometre (SI symbol: km; /ˈkɪləmiːtər/ or /kɪˈlɒmətər/), spelt kilometer in American and Philippine English, is a unit of length in the International System of Units (SI), equal to one thousand metres (kilo- being the SI prefix for 1000). It is the preferred measurement unit to express distances between geographical places on land in most of the world; notable exceptions are the United States and the United Kingdom where the statute mile is used.

Irish measure or plantation measure was a system of units of land measurement used in Ireland from the 16th century plantations until the 19th century, with residual use into the 20th century. The units were based on "English measure" but used a linear perch measuring 7 yards (6.4 m) as opposed to the English rod of 5.5 yards (5.0 m). Thus, linear units such as the furlong and mile, which were defined in terms of perches, were longer by a factor of 14:11 (~27% more) in Irish measure, while units of area, such as the rood or acre, were larger by 196:121 (~62% more). The Weights and Measures Act 1824 (5 Geo. 4. c. 74) mandated the use throughout the British Empire of "Imperial measure", also called "statute measure", based on English measure. Imperial measure soon replaced Irish measure in the use of the Dublin Castle administration, but Irish measure persisted in local government, and longer still in private use.

The chain (abbreviated ch) is a unit of length equal to 66 feet (22 yards), used in both the US customary and Imperial unit systems. It is subdivided into 100 links. There are 10 chains in a furlong, and 80 chains in one statute mile. In metric terms, it is 20.1168 m long. By extension, chainage (running distance) is the distance along a curved or straight survey line from a fixed commencing point, as given by an odometer.

The chain has been used since the early 17th century in England, and was taken by British settlers during the colonial period to other countries around the globe. In the United Kingdom, there were 80 chains to the mile, but until the early nineteenth century the Scottish and Irish customary miles were longer than the statute mile; consequently a Scots chain was about 74 (imperial) feet, an Irish chain 84 feet. These longer chains became obsolete following the adoption of the imperial system of units in 1824. In India, "metric chains" of exactly 20 metres (65.62 feet) are used, along with fractions thereof.

Sir Ernest Henry Shackleton (15 February 1874 – 5 January 1922) was an Anglo-Irish Antarctic explorer who led three British expeditions to the Antarctic. He was one of the principal figures of the period known as the Heroic Age of Antarctic Exploration.

Born in Kilkea, County Kildare, Ireland, Shackleton and his Anglo-Irish family moved to Sydenham in suburban south London when he was ten. Shackleton's first experience of the polar regions was as third officer on Captain Robert Falcon Scott's Discovery Expedition of 1901‍–‍1904, from which he was sent home early on health grounds, after he and his companions Scott and Edward Adrian Wilson set a new southern record by marching to latitude 82° S. During the Nimrod Expedition of 1907‍–‍1909, he and three companions established a new record Farthest South latitude of 88°23′ S, only 97 geographical miles (112 statute miles or 180 kilometres) from the South Pole, the largest advance to the pole in exploration history. Also, members of his team climbed Mount Erebus, the most active Antarctic volcano. On returning home, Shackleton was knighted for his achievements by King Edward VII.

Mercury-Redstone 3, or Freedom 7, was the first United States human spaceflight, on May 5, 1961, piloted by astronaut Alan Shepard. It was the first crewed flight of Project Mercury. The project had the ultimate objective of putting an astronaut into orbit around the Earth and returning him safely. Shepard's mission was a 15-minute suborbital flight with the primary objective of demonstrating his ability to withstand the high g-forces of launch and atmospheric re-entry.

Shepard named his space capsule Freedom 7, setting a precedent for the remaining six Mercury astronauts naming their spacecraft and the format of their names, the number 7 later included in all the crewed Mercury spacecraft names not to honor NASA's first group of seven astronauts but it stood for the McDonnell Model #7 space capsule used in the Mercury Program. His spacecraft reached an altitude of 101.2 nautical miles (116.5 statute miles, 187.5 km) and traveled a downrange distance of 263.1 nautical miles (302.8 statute miles, 487.3 km). It was the fourth Mercury flight launched with the Mercury-Redstone Launch Vehicle, from Cape Canaveral, Florida, close to the Atlantic Ocean.