Physical Science

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Physical Science
I have learned from my twenty years of service in the U.S. Air Force, significant background knowledge of the history of the space shuttle. In September 1969, two months after the first manned lunar landing, a Space Task Group appointed by the President of the United States to study the future course of U.S. space research and exploration made the recommendation that "…the United States accept the basic goal of a balanced manned and unmanned space program. To achieve this goal, the United States should …develop new systems of technology for space operation…through a program directed initially toward development of a new space transportation capability…" According to Cox (1962), many responsible observers felt that we were devoting too many of our resources to increasing an already affluent volume of private consumption and too little for public services, including space-flight programs. In early 1970, NASA initiated extensive engineering, design, and cost studies of a space shuttle. These studies covered a wide variety of concepts ranging from a fully reusable manned booster and orbiter to dual strap-on solid propellant rocket motors and an expendable liquid propellant tank. Each concept evaluated development risks and costs in relation to the suitability and the overall economics of the entire system. On January 5, 1972, President Richard M. Nixon announced that NASA would proceed with the development of a reusable low cost space shuttle system. NASA and its aerospace industry contractors continued engineering studies through January and February of 1972; finally on March 15, 1972, NASA announced that the shuttle would use two solid propellant rocket motors. The decision was based on information developed by studies that showed that the solid rocket system offered lower development cost and lower technical risk. On September 17, 1976, the first orbiter spacecraft, Enterprise, was rolled out. A total of thirteen test flights were performed. The Enterprise was built as a test vehicle and not equipped for space flight. Five captive flights, with the Enterprise perched atop a 747 jumbo jet with no crew and unpowered, were conducted to test the structural integrity of the craft. Three crewed captive flights followed with the crew operating the flight control systems in preparation for the first orbiter free flight. Finally, five free flights occurred with an astronaut crew separating the orbiter from the 747 shuttle carrier and maneuvering to a landing at Edwards Air Force Base. For all of the captive flights and the first three free flights, the orbiter was outfitted with a tail cone covering its aft section to reduce aerodynamic drag and turbulence. The final two free flights were made without the tail cone, and the three simulated space shuttle main engines and two orbital maneuvering system engines were exposed aerodynamically. After numerous tests across the United States, the Enterprise was ferried across the Atlantic for several air shows across Europe. Finally, on November 18, 1985, the Enterprise was ferried from Kennedy Space Center to Washington, D.C. and became the property of the Smithsonian Institution. The second orbiter, Columbia, was the first to fly into space. Perched atop the 747 shuttle carrier, Columbia arrived at Kennedy Space Center from Dryden Flight Research Facility on March 25, 1979 to be readied for the space shuttle's first flight on April 12, 1981. The space shuttle is launched in a vertical position, with thrust provided by two solid rocket boosters, called the first stage, and three space shuttle main engines, called the second stage. At liftoff, both the boosters and main engines are operating. To achieve orbit, the shuttle must accelerate from zero to a speed of almost 28,968 kilometers per hour (18,000 miles per hour), a speed nine times as fast as the average rifle bullet. To travel that fast, it must reach an altitude above most of Earth's atmosphere so...
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