Word: nasa
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Dates: during 1980-1989
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Ever since last November, the new space shuttle Challenger has been perched proudly on its Florida pad, pointing skyward like an anxious eagle. Last week NASA officials gloomily conceded that their $1 billion bird may have to sit in its nest a while longer. The latest delay involves the most serious problem yet encountered with the troubled Challenger: a basic defect in design that requires overhauling all three of the main engines. Unless the flaw can be quickly corrected, the problem could create a horrendous backup of civilian and military satellites waiting to be carried aloft and add millions...
Ironically, the defect stems, at least in part, from NASA'S own supercaution. To improve performance, Challenger's engines were built to operate at 9% greater thrust than those of the first orbiter, Columbia, when the throttle is fully opened. Realizing that this extra power would vibrate the spacecraft more violently, NASA engineers at the Marshall Space Flight Center made a design change. They ordered reinforcement of the metal piping that carries hot, gaseous hydrogen fuel into the small chamber where the engines are first fired up and begin revving to their full 480,000 lbs. of thrust...
...testimony before a congressional subcommittee on science and technology last week, Air Force Lieut. General James A. Abrahamson, NASA'S associate administrator and boss of the shuttle program, said that discovery of the defect was a tribute to the space agency's quest for safety. He might have added that it was also because of an odd bit of luck. In late January, only days before Challenger's originally scheduled liftoff, NASA inspectors discovered that hydrogen was leaking from the No. 1 engine...
...NASA is pressing for a cure because SAS can disrupt short-term flights. As a temporary remedy, astronauts routinely take along pills containing a combination of scopolamine, a drug that blunts sensations, and dextroamphetamine, a stimulant to counteract scopolamine's dulling effects on the body and mind. When the pills failed to help Lenoir, NASA's chief flight surgeon Sam Pool advised from Houston ground headquarters that Lenoir also take Phenergan, an antihistamine, and Dalmane if he needed a sleep medication. But the combination of potent drugs is not an ideal solution since it can impair coordination...
...sound sleep becomes elusive. The heart's size shrinks by 10%. Astronauts exercising on land after a flight have a higher pulse rate than they did before space. "We think it takes only 48 hours in space for this change in the heart to take place," says NASA's Johnson. The heart apparently returns to normal within a year of returning to earth...