Astronaut - astronomy.

Astronaut - astronomy. I INTRODUCTION Astronaut, crew member on piloted spaceflights. The term astronaut comes from the Latin words astrum ("star") and nauta ("mariner") and is used mostly in Englishspeaking countries. Russians who go into space are called cosmonauts. French space travelers are called spationauts. The International Astronomical Federation defines space travel as beginning 100 km (62 mi) above Earth, so some airplane pilots are considered astronauts. See Space Exploration. Piloted spaceflight is an important aspect of space exploration. Humans in space can retrieve and repair satellites that might be useless otherwise. Studies of the effects of space on the human body have provided important medical knowledge for humans on Earth. Astronauts can perform experiments in space that machines cannot. Current piloted spaceflight may help scientists develop ways to allow humans to survive in space longer, which will be necessary if humans ever visit or colonize other planets. Astronauts came into being in the late 1950s, when both the United States and the former Union of Soviet Socialist Republics (USSR) began piloted spaceflight programs. Both countries chose military pilots as the first astronauts. No one really knew what astronauts would be required to perform or how they would be required to behave, but it made sense to choose people with proven flying abilities and reliability in dangerous environments. Also, some of the earliest spacecraft were based on the high-performance aircraft that these pilots were accustomed to flying. Modern astronauts include scientists, engineers, medical doctors, and educators, as well as pilots. II MILESTONES The journey of humans into space began with the launch of the first satellite--the Soviet Sputnik--in 1957. The USSR was also the first country to send a person, Yuri Gagarin, into space. Gagarin was the first human to orbit Earth, as well as the first person in space, when he flew aboard Vostok 1 in April 1961. The United States first sent a person, astronaut Alan B. Shepard, Jr., into space in May 1961. The first U.S. astronaut to orbit Earth was John H. Glenn, who made a three-orbit flight in February 1962. Soviet cosmonaut Valentina Tereshkova became the first woman to go into space in June 1963. The first humans to set foot on the Moon were U.S. astronauts Neil Armstrong and Buzz Aldrin, who landed the lunar module of Apollo 11 on the surface of the Moon on July 20, 1969. When John Glenn flew aboard a space shuttle mission in 1998 at the age of 77 he became the oldest person ever to go into space. In 2004 Mike Melvill became the first person to pilot a privately owned spacecraft into orbit. In all, more than 400 people from more than 20 countries have flown in space. Russian cosmonaut Valeriy Polyakov holds the record for spending the most consecutive days in space. He spent 438 days aboard the Mir space station in 1994 and 1995. Astronaut Shannon Lucid of the United States spent 188 days aboard Mir in 1996, giving her the U.S. record for long-duration spaceflight. III WHAT DO ASTRONAUTS DO? The very first astronauts were little more than human test subjects, but today's astronauts are pilots, scientists, and engineers with active roles in many aspects of their missions. In the first ever piloted spaceflight, Vostok 1, cosmonaut Yuri Gagarin had little more to do than go along for the ride while a ground crew controlled the spacecraft by remote control. The instruments had an override code that Gagarin could have used if something went wrong, but he did not know the code before the flight. It was sealed in an envelope attached to the capsule's wall. The first U.S. astronauts--those in the Mercury program--had some control over their spacecraft. Alan Shepard tested the manual controls of the Mercury capsule in space and manually fired the retrorockets that slowed the capsule enough to allow it to fall back to Earth. Gordon Cooper, the astronaut aboard the last Mercury flight, was forced to land his capsule manually when the automatic reentry system developed electrical problems. As missions grew more complex, astronauts began to control more aspects of the mission. Cosmonauts and astronauts of the Soviet Voskhod and U.S. Gemini programs studied the effects of weightlessness, left the spacecraft in pressurized spacesuits to perform extravehicular activities (EVAs) or spacewalks, and guided their capsules close enough to other spacecraft to dock with them. During the Apollo program, astronauts spent days on the surface of the Moon exploring and performing experiments. Astronauts aboard the U.S. Skylab space station and the Soviet Salyut and Mir stations began to spend months in space at a time. Astronauts who fly aboard the space shuttle or stay aboard the International Space Station often spend months or years developing their missions. Astronauts have significant roles in planning and carrying out scientific experiments and performing tasks while in space. The U.S. National Aeronautics and Space Administration (NASA) designates space shuttle astronauts as pilots, mission specialists, and payload specialists. Every space shuttle mission includes at least two pilots and at least two mission specialists. Pilots can have one of two jobs on a mission: They can be the mission commander or the mission pilot. Commanders work with controllers on the ground to make all critical decisions during the mission. Commanders also fly the shuttle in space and during landing and can take over from the space shuttle's computers at any time. They also monitor the shuttle's key systems--such as guidance, navigation, and flight control--throughout the mission. The mission pilot acts as a backup to the commander. The pilot has the same training as, but usually less experience than, the commander. Mission specialists are scientists and engineers who deal with the specific experiments and equipment onboard for the mission. They must have detailed knowledge of shuttle systems and of the equipment and objectives associated with that mission. Their duties in orbit may include leaving the spacecraft for spacewalks, operating the space shuttle's robot arm (called the remote manipulator system), deploying satellites, and operating onboard experiments. On every space shuttle flight, one mission specialist acts as flight engineer during launch and landing to support the pilot. Two mission specialists in each mission are assigned emergency spacewalk duties, just in case the mission requires an unexpected spacewalk. Payload specialists serve on some space shuttle missions. Payload specialists are not astronauts by profession, but receive months of space shuttle training before their mission. The science team for the mission selects its own payload specialists. Payload specialists work on specific experiments or equipment with which they have significant experience. Because payload specialists are more scientists or engineers than astronauts, they are able to provide greater expertise than a career astronaut could obtain in the 18 to 24 months before a mission. Often a mission specialist and a payload specialist will pair up during training and during the mission to create a team with extensive experience in both space shuttle and scientific systems. Before the space shuttle Challenger exploded in 1986 (see Challenger Disaster), NASA allowed a few people who were neither scientists nor astronauts aboard the space shuttle as payload specialists. These included U.S. senator Jake Garn and teacher Christa McAuliffe. After the Challenger explosion, NASA began to require that payload specialists have more space shuttle training and extensive expertise in the mission's scientific objectives. All crew members usually share in space housekeeping duties such as meal preparation, cleaning, and stowing gear. Between spaceflights, astronauts support other space shuttle missions through jobs in Mission Control or at the launch site, by advising teams that are planning future payloads and missions, or by helping test future experiments and equipment. Every operation during a flight is important and interesting, but many might be boring to an observer. Much of an astronaut's job is entering computer instructions, preparing samples, making measurements, recording data, fixing what breaks, and adjusting the checklist when something unexpected happens. Sometimes astronauts retrieve or repair satellites, rendezvous or dock with other spacecraft, and do important emergency repairs. The adaptability of the human crew is crucial to the success of missions in which unexpected things happen. IV ASTRONAUT SELECTION The first American and Soviet astronauts were selected from the military only. As space travel has become more frequent and the goals of missions have become more diverse, astronaut selection has broadened to include scientists and other civilians. A United States Specialists at the U.S. Air Force School of Aerospace Medicine first defined criteria for selecting astronauts in 1957. Candidates were to be younger than 40 years old and no more than 180 cm (5 ft 11 in) tall (to fit the small Mercury capsules), have a B.S. degree, and be a graduate of a military test pilot school with jet qualifications and at least 1,500 hours of flight time. Psychological health was even more important. Astronauts had to handle isolation and possibly fear and had to be adventurous, but not foolhardy. Astronauts needed integrity, ability, and self-confidence to earn their associates' trust and confidence. NASA selected the first seven U.S. astronauts from 473 candidates after exhaustive technical, medical, and psychological testing. NASA made only a few small changes in criteria until 1965, when it selected the first six scientist-astronauts. NASA required scientist-astronauts to have a Ph.D. degree in addition to meeting the physical and psychological standards. NASA began astronaut selection for space shuttle missions in 1977. The height and age limits are broader for the space shuttle, but education and physical and mental health remain very important. Personal qualities like reliability, trustworthiness, and excellent communication skills are also important. Shuttle astronauts must be highly trained generalists who can handle many changes in duties and work effectively within very diverse teams. Both pilot astronauts and mission specialist applicants must have a bachelor's degree in math, science, or engineering and at least three more years of progressively more responsible professional experience. The selection process thoroughly examines the quality of an applicant's educational and work experience at least as far back as the applicant's undergraduate degree. Pilot applicants must pass a rigorous physical and have at least 1,000 hours of flying time as the pilot in command. Mission specialist applicants must pass a slightly less rigorous physical. Pilots must have vision at least as good as 20/50 and mission specialists must have vision of 20/150 or better. With glasses or contact lenses, astronauts' vision must be 20/20. B USSR The USSR also went to its air force to choose the country's first cosmonauts in 1960. More than 3,000 young pilots volunteered for the first cosmonaut selection. After exacting physical and psychological tests, the USSR chose 21 men. The requirements were that the men be younger than 30 years of age, be less than 170 cm (5 ft 7 in) tall, and be military officers who had graduated from the Soviet air force equivalent of a U.S. junior college. Despite the focus on the air force, none of the new astronauts were test pilots and the most experienced pilot among them had only 900 hours of flying time. One of the requirements of early astronaut selection for both the United States and the USSR seemed to be that the candidates be male. The USSR changed that in 1962 when it chose five female astronaut candidates. All five were veteran parachutists in the Soviet air force. The USSR eventually relaxed the age and fitness requirements, but also required that cosmonauts have more education. The first civilian cosmonauts were chosen in 1963. Many military and civilian candidates joined the ranks of cosmonauts during the next three decades. After the USSR collapsed in 1991, the cosmonaut program shrank considerably. The Russian Space Agency took over a few years later. C Other Countries The USSR (later Russia) and the United States have always controlled the only vehicles capable of launching humans into space, so only Soviets and Americans went into space for the first 15 years of piloted spaceflight. In the mid-1970s the USSR began recruiting a few cosmonauts from other nations. The requirements were the same for these "guest cosmonauts" as they were for Soviet cosmonauts. The United States first invited foreign citizens to fly aboard the shuttle in the early 1980s, with the beginning of the European-designed Spacelab missions. The first non-Americans to fly aboard the shuttle were European scientists. These Spacelab payload specialists were required to pass physical tests and undergo astronaut training, but their scientific backgrounds were also key in their selection. Nations other than the United States and the USSR began developing formal astronaut programs in the 1980s. These programs were designed to provide a pool of astronauts that could fly aboard U.S. or Soviet spacecraft. Canada was the first nation to develop a team of astronauts. The first candidates were chosen in 1983 with similar criteria to that of the U.S. shuttle astronaut program. France chose its first group of spationauts in 1985. Spationauts must be between 25 and 35 years old, have a degree in engineering, science, or medicine, and have professional experience in their field. Japan chose three scientists to become astronaut candidates in 1985. Japanese astronauts must be under 35 years of age and have a B.S. degree and three years of work experience in their field. The former West Germany announced its first group of astronauts in 1987. The Agenzia Spaziale Italiana (ASI, the Italian Space Agency) chose its first group of four astronaut candidates in 1989. In 1991 the European Space Agency (ESA) created a pool of astronauts from its 11 member nations and Canada. Almost all were scientists. This pool has become the primary source for Canadian and European astronauts on the shuttle. The ESA will also provide astronauts for the International Space Station (ISS). Language skills are important now that astronauts of many countries are flying together. Astronauts flying aboard the space shuttle must be able to speak English and astronauts aboard the space station Mir were required to speak Russian. V ASTRONAUT TRAINING Astronaut training must try to prepare the astronauts for the planned and the unexpected. Astronauts become familiar with the spacecraft and instruments that they will be using and the tasks that they expect to perform before they go into space. A Early Astronauts The earliest astronauts, those with the Soviet Vostok and U.S. Mercury programs, faced the prospect of being the first people to go into space. Their training attempted to cover every aspect of their missions, every physical and psychological hurdle they might have to face, and many of the things that mission planners thought might go wrong. Mercury astronauts became familiar during training with the Mercury spacecraft and the pressure suits that they would wear inside the capsule. They practiced using the capsule controls in a variety of environments, including inside a centrifuge that replicated the huge force that the acceleration of launch and landing would apply to the astronauts' bodies. The astronauts went through intensive survival training, especially water survival, since their capsules were to parachute down into the ocean. They also had classroom training in astronomy, aeronautics, and space medicine. Training for Mercury began in April 1959 and ended with each astronaut's mission. (The first piloted Mercury mission was in May 1961.) The training for Vostok cosmonauts was very similar to that for the Mercury astronauts, but the Soviet doctors kept tighter control over the cosmonauts' physical conditioning. Vostok training began in February 1960 and Vostok 1 launched in March 1961. Training for Gemini, Voskhod, and Apollo programs built on the experience of the earlier astronauts. Each program required the astronauts to learn new tasks, but the basic training structure changed little. Space shuttle and space station astronauts and cosmonauts usually go through at least a year of training before their first mission. The training can include classroom work, simulator training, survival training, and other projects. Many missions require specific training in addition to the general astronaut training, especially if the mission will involve complicated experiments or maneuvers. B Space Shuttle Training People who pass NASA screening are officially called astronaut candidates. A candidate must complete a one-year training and evaluation period to be designated as an astronaut and be eligible for flight-related jobs. During this year of training, classroom work covers topics such as spacecraft design, aeronautics, orbital mechanics, space medicine, meteorology, oceanography, and astronomy. Candidates begin to learn about the space shuttle through self-study workbooks, computer-based training aids, and presentations by experienced astronauts, designers, and flight engineers. Candidates also go through basic water survival, land survival, and high-altitude training. Candidates are expected to use their own time to stay physically fit and meet flight time requirements. After the candidate year, a new astronaut's first assignments are supporting jobs for shuttle flights. An astronaut may help design the experiments or cargo that the space shuttle will carry. Other common jobs include helping prepare the launch site, testing software, and establishing procedures for the mission. Astronauts perform these support jobs until they are assigned to a specific flight, and they return to support positions upon their return. Training for a particular mission is designed to take astronauts from basic understanding of concepts into detailed knowledge of the specifics of the mission. For example, astronauts may build on their candidate training about orbital mechanics to set the exact geometry and velocity of the orbit the space shuttle will follow on the mission. Depending on the assigned role and prior flight experience, training may last as short as nine months, or as long as 24 months for complex scientific flights with many experiments. Most flight training occurs either in simulators or with the real flight hardware. Different simulators fill various training needs. NASA's Shuttle Mission Simulators (SMS) can faithfully simulate nearly every element of a flight (but not weightlessness or the real view out the window). Teams of instructors program computers with scripts of events that test the knowledge of both the shuttle crew and the ground control team, to teach them to work together effectively. On Spacelab flights, these scenarios also include the international science teams, who are immersed in the scenario along with Mission Control and the crew through networked simulation computers. Intensive SMS sessions fill most of a crew's time in the last few months before flight, turning the individual skills and knowledge that have been built in other trainers and simulators into team skills. Shuttle pilot astronauts practice the final 9,000 m (30,000 ft) of approach and landing in a specially modified jet called the Shuttle Training Aircraft (STA). Computers, special wing flaps, and engines operating in reverse thrust make this sleek jet plummet toward Earth like a space shuttle, and one side of the cockpit has real shuttle displays and controls. Astronauts study procedures and hone skills for EVAs, or spacewalks, in the Neutral Buoyancy Laboratory, an immense swimming pool in which full-sized mock-ups of the shuttle or other flight hardware are submerged. Astronauts practice boarding the space shuttle and emergency procedures for leaving the shuttle in detailed mock-ups of the shuttle crew cabin. Mission specialists verify checklists and practice operations with the robotic arm in the Manipulator Development Facility. Virtual reality tools are gaining use in astronaut training for very complex jobs such as Hubble Space Telescope repair missions. Some of the training simulators model the experiments, satellites, and other equipment that make up the mission's cargo, but mission specialists go to the laboratory or facility preparing the equipment to gain detailed understanding of how it is built and how it will operate. The longer flights and complex scientific experiments that are increasingly common can have many possible unpredictable results or events, so training for these missions must include detailed understanding of the equipment and the objectives of the mission or experiment. This way, astronauts will be able to make sound judgments based on the situation. Contributed By: Kathryn D. Sullivan Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.