Science Fact of the Week 34 – The Space Shuttle
NASA’s Space Shuttle is the world’s first reusable space craft. It was first conceived during the years of the Apollo lunar program and was intended to service space stations, lower the costs of space travel and make access to the moon and beyond more routine. After numerous delays, the first of five orbiters, Columbia, lifted off on the 12th April 1981.
The shuttle is composed of three parts: the orbiter (the aeroplane-like crew and cargo carrying craft that most people think of as the shuttle); a large external tank (ET) that holds the liquid oxygen and liquid hydrogen fuel; and two solid rocket boosters (SRBs) packed with powdered aluminium and rubber fuel. The SRBs provide 6 million pounds of thrust at takeoff, before being jettisoned to parachute into the ocean, where they are recovered for re-use. The ET is jettisoned soon after, and burns up during atmospheric re-entry. The orbiter is over 37 metres long, has a wing span of nearly 24 metres and weighs 78 tonnes when empty. The re-entry of the orbiter is controlled by computers.
All Shuttle missions launch from the Kennedy Space Center (sic), Florida. The Space Shuttle has been used in recent years to repair and update the International Space Station, the Hubble Telescope and other major satellites although significant research is carried out on board as well. The shuttle generally lands in the Kennedy Space Center but if weather conditions are unfavourable, it may land in Edwards Airforce Base in California. In these cases, the orbiter must be ferried back to Florida on top of a Boeing 747 (see picture below).
The major low in the Space Shuttle's 28 years in service came when Space Shuttle Columbia blasted off on the 16th January 2003, and though no one knew it at the time, the orbiter sustained fatal damage just seconds after lift-off. According to the Columbia Accident Investigation Board, a suitcase-sized chunk of foam came loose from the ET, punching a hole in insulating tiles on the craft's wing. During re-entry, 16 days later, super-hot atmospheric gases penetrated the wing, causing it to shear off. The orbiter then disintegrated, with the loss of all seven astronauts on board. This was the second disaster for the program, having lost the Challenger in 1986 when it exploded on launch.
The Space Shuttle is due to be replaced by 2015 by the Are I rockets and Orion crew capsule.