NASA - astronomy.

NASA - astronomy. I INTRODUCTION NASA or National Aeronautics and Space Administration, agency of the United States government responsible for developing space exploration. NASA conducts both human and unpiloted spaceflights, and also trains astronauts and carries out scientific experiments in space. NASA's areas of space research include planetary science, astrophysics, astronomy, Earth science, astrobiology, and aerospace medicine. The agency studies the performance and design of airplanes (aeronautics) and rockets as well. NASA has a wide range of educational outreach programs in the form of public lectures, Websites, and television (NASA TV) for classrooms and the general public. In addition, NASA works to increase international alliances for space activities, and to establish partnerships between private companies and government agencies in the aerospace industry. NASA is a civilian agency, separate from the military and intelligence-gathering space programs conducted by the United States Department of Defense (DOD). II ORGANIZATION OF NASA NASA is based in Washington, D.C., and is under the guidance of the president of the United States. The president is mainly responsible for determining NASA's budget, which directly affects the mission and goals of the agency. NASA is organized into four main mission directorates: the Aeronautics Research Mission Directorate, the Exploration Systems Mission Directorate, the Science Mission Directorate, and the Space Operations Mission Directorate. NASA employs thousands of scientists, engineers, and technicians at its major installations across the country. These facilities include the John F. Kennedy Space Center in Merritt Island, Florida; the Lyndon B. Johnson Space Center in Houston, Texas; the Goddard Space Flight Center in Greenbelt, Maryland; the George C. Marshall Space Flight Center in Huntsville, Alabama; and the Jet Propulsion Laboratory in Pasadena, California. Scientists from institutions outside the U.S. government and from other countries commonly work with NASA on particular projects and space missions. Satellites launched by NASA are used by the National Oceanic and Atmospheric Administration (NOAA) and other government agencies. Although NASA is a civilian agency, it sometimes shares launch facilities with the U.S. Air Force and has launched satellites and space probes from the Cape Canaveral Air Force Station (CCAFS), next to NASA's Kennedy Space Center in Florida, and from Vandenberg Air Base in California. Many members of NASA's astronaut corps are also active members of the military. NASA has used research conducted by the military such as the X-15 piloted rocket program in the 1960s and the Clementine Moon orbiter. Throughout its history, NASA has faced budget and funding challenges, and has had to prioritize a mix of human space missions and unpiloted satellite and robotic missions, along with aeronautical research. Developing and operating human space programs have been more expensive than unpiloted programs. Debate has centered on whether robotic space exploration using orbiters, landers, and rovers is more economical and scientifically productive than human missions. In turn, decisions must be made about the size and scale of resources devoted to different areas of research such as Earth science, astrophysics, extrasolar planets, or planetary science within our solar system. III FOUNDING AND EARLY HISTORY OF NASA The National Aeronautics and Space Administration was established in 1958 under the National Aeronautics and Space Act. The United States Congress passed the "NASA Act" in the wake of the Soviet Union's successful launch of the first space satellite (Sputnik) in 1957. The act established NASA as a civilian agency that would use space for peaceful purposes. President Dwight Eisenhower wanted to separate civilian space activities from the military space program conducted by the Department of Defense. NASA replaced the National Advisory Committee for Aeronautics (NACA) that was created by the United States Congress in 1915. NASA absorbed various aviation and space organizations that were already established, enabling a single agency to coordinate efforts effectively among all interested parties: scientists, engineers, universities, and politicians. From the beginning NASA was a major player in what became known as the "space race" between the United States and its Cold War rival, the former Union of Soviet Socialist Republics (USSR). Both nations worked to develop rockets that could carry satellites and piloted missions into space. Soviet scientists scored the first victory on October 4, 1957, when they launched the beach-ball-sized artificial satellite, Sputnik (later referred to as Sputnik 1), into orbit around Earth. The USSR went on to record several more historic firsts, including a series of dramatic achievements that culminated on April 12, 1961, when cosmonaut Yuri Gagarin became the first human to orbit the planet in a spacecraft. Just a few weeks later, on May 5, the United States launched its first piloted spacecraft in which astronaut Alan B. Shepard, Jr., made a suborbital flight (a complete orbit of Earth was not made). This American space success prompted President John F. Kennedy to propose a program to send humans to the Moon before the end of the decade of the 1960s. IV NASA'S HUMAN SPACE PROGRAMS The United States finally caught up with the USSR on February 20, 1962, when a Mercury rocket carried John Glenn around Earth three times (see Mercury program). In 1963 Mercury gave way to the Gemini program, which would send two astronauts into space in a bigger and better version of the Mercury spacecraft. The Gemini program was phased out in 1967 by the Apollo program, a $25-billion project devoted to fulfilling President Kennedy's goal of landing a U.S. astronaut on the Moon by the end of the decade. In May 1969 Apollo 10 came within 15,240 m (50,000 ft) of the Moon's surface. Two months later, on July 20, 1969, Apollo 11 astronaut Neil Armstrong became the first human being to walk on the Moon. His words at that moment are part of history: "That's one small step for a man, one giant leap for mankind." Five more Apollo missions reached the Moon. The only failed mission occurred in 1970 when technical problems forced Apollo 13 to return to Earth before landing on the Moon. Apollo's final Moon mission was completed in December 1972. Apollo technology was used in 1973 to launch NASA's first space station, Skylab, where astronauts could work and live in space for several months. Apollo-Soyuz in 1975 brought the United States and the USSR together for a joint mission in Earth orbit. NASA's next major human space program was the space shuttle, which had its first flight in 1981. The shuttle was designed to be a reusable space vehicle that could be launched on a regular schedule to carry humans, scientific equipment, satellites, space probes, and cargo into space. A fleet of five shuttles was built. The shuttle was launched with a combination of liquid fuel and solid fuel rockets and glided back from space to land like an aircraft. The original ambitions of the shuttle program were only partly realized. Fewer shuttle launches were made than planned. Catastrophic accidents destroyed the Challenger shuttle after launch in 1986 and the Columbia shuttle during reentry in 2003, killing both crews. Investigations traced the accidents to design flaws and to management problems. Both accidents led to design and procedure changes, and to a temporary stoppage of shuttle flights. Following the Columbia disaster, NASA also announced plans to retire the shuttle in 2010, after completion of the International Space Station (ISS), a human orbital research facility. The Constellation program is NASA's successor to the space shuttle. The program uses a human-piloted capsule design similar to Apollo technology, and is intended to be safer than the space shuttle. Plans call for the Constellation program to take astronauts back to the Moon and on to Mars, and possibly to nearby asteroids. The first flight of the Orion piloted capsule is scheduled for 2015. The long gap between the retirement of the space shuttle and the beginning of Orion piloted flights concerns some NASA officials, however. The training of astronauts and the staff expertise for operating human-piloted missions may suffer. Russian space capsules will take American astronauts to the International Space Station between the end of the shuttle program and the beginning of the Constellation program. NASA is also an active participant in the construction and staffing of the International Space Station. The United States, Canada, Japan, Russia, and nine members of the European Space Agency (ESA) collaborate on this project. At least one NASA astronaut is included in each of the ISS crews that have continuously resided on the station since 2000. V NASA'S UNPILOTED SPACE MISSIONS Beginning in the 1960s, NASA launched a series of spacecraft that flew by all the major planets of the solar system from Mercury to Neptune, as well as by asteroids and comets. Notable missions include the Mariner series to Mercury, Venus, and Mars; the Pioneer craft to Jupiter and Saturn; and the Voyager probes to Jupiter, Saturn, Uranus, and Neptune. A flyby of the dwarf planet Pluto is scheduled for 2015. NASA has also put space probes into orbit around the Sun, the Moon, Venus, Mars, Jupiter, and Saturn, with a Mercury orbiter set for 2011, and an asteroid belt orbiter for 2015. These orbiting space probes include Ulysses around the Sun; Lunar Orbiter around the Moon; Magellan around Venus; Viking, Mars Global Surveyor, Mars Odyssey, and Mars Reconnaissance Orbiter around Mars; Galileo to Jupiter and its moons; and Cassini to Saturn and its moons and rings. NASA robot probes have landed on the Moon with Surveyor and on Mars with Viking, Mars Pathfinder, and Mars Exploration Rovers. More Mars landers are scheduled, with a possible return of samples in the future. NASA also collaborated on the Huygens probe that was attached to Cassini and landed on Saturn's moon Titan. Other NASA missions such as Genesis and Stardust have returned samples to Earth of the particles emitted by the Sun and by comets in space. NASA has also helped design, launch, and operate a fleet of space telescopes, including the Hubble Space Telescope (HST), the Infrared Space Observatory, the Spitzer Space Telescope, the Chandra X-Ray Observatory, the Compton Gamma Ray Observatory, and the planned James Webb Space Telescope. As part of research into Earth science, NASA launches satellites that monitor Earth from space to observe weather, climate, oceans, land, and resources, as well as auroras and the magnetosphere. In addition, sophisticated scientific NASA satellites have studied astronomical and astrophysical phenomena, including black holes and radiation from the big bang that started the universe. Other NASA space observatories look for evidence of extrasolar planets around other stars. NASA also helps support groundbased telescopes that study objects in space or search for asteroids and comets that come near Earth's orbit. Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.