NASA Space Shuttle Discovery (OV-103) Discovery, the third orbiter to become operational at Kennedy Space Center, was named after one of two ships that were used by the British explorer James Cook in the 1770's during voyages in the South Pacific that led to the discovery of the Hawaiian Islands. Another of his ships was the Endeavour, the namesake of NASA's newest orbiter. Cook also used Discovery to explore the coasts of southern Alaska and northwestern Canada. During the American Revolutionary War, Benjamin Franklin made a safe conduct request for the British vessel because of the scientific importance of its research. Other famous ships have carried the name Discovery, including one used by Henry Hudson to explore Hudson Bay in Canada as well as search for what was hoped to be the northwest passage from the Atlantic to the Pacific in 1610 and 1611. Another, based on whaling ship design, was used by the British Royal Geographical Society for an expedition to the North Pole in 1875. This organization then built another Discovery in 1901 to conduct its Antarctic expedition that concluded in 1904. This ship still exists and is being preserved by the Society. In the day-to-day world of Shuttle operations and processing, Space Shuttle orbiters go by a more prosaic designation. Discovery is commonly referred to as OV-103, for Orbiter Vehicle-103. Empty Weight was 151,419 lbs at rollout and 171,000 lbs with main engines installed. In 2002, Discovery underwent an over two year Orbiter Maintenance Down Period that provided 99 upgrades and 88 special tests, including a number of changes to make it safer for flight. Each wing contains new sensors that are able to take 20,000 samples per second and detect micrometeorite or other impacts. There are 22 temperature sensors and 66 accelerometers. Discovery also has a new 50-foot inspection boom that can be used to check Discovery's underside for damage.