Feb 17 1978
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(New page: NASA's Skylab workshop launched in May 1973 might descend to 150 nautical miles (173 statute miles, 278km) altitude and begin reentry into earth's atmosphere as early as late summer of...)
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NASA's Skylab workshop launched in May 1973 might descend to 150 nautical miles (173 statute miles, 278km) altitude and begin reentry into earth's atmosphere as early as late summer of 1979, JSC Roundup reported, citing orbit data from the North American Air Defense Command's satellite trackers, the Smithsonian Astrophysical Observatory, and the Swiss federal observatory. NASA would try two ways of postponing Skylab reentry: first, to reactivate the workshop's thruster attitude-control system in the spring of 1978 and put it into a very slow tumble, decreasing atmospheric drag and perhaps adding several months to its orbital lifetime; second, to use a teleoperator retrieval system (TRS) launched on an early Space Shuttle mission (about Oct. 1979) and flown by remote control to dock with Skylab. Once docked, the TRS propulsion system could either raise Skylab's orbit or control its reentry.
Although Skylab would break up and burn during descent, some debris would probably survive reentry, and probably would land in an ocean, because 80% of the Skylab orbit had been over water (between 50°N and 50°S). Skylab, largest payload in earth orbit at 85 tons, and about 96ft in length, had been manned during 3 missions by 3 different astronaut crews. When the last crew had left Skylab, NASA estimated the workshop would remain in orbit until 1983; however, its altitude had dropped more rapidly than expected because of increased atmospheric drag caused by sunspot activity. (JSC Roundup, Feb 17/78, 1; DFRC X-Press, Feb 10/78, 2; Marshall Star, Feb 8/78, 4; W Post, Feb 2/78, A-2; C Trib, Feb 6/78, Sec. 1; Nature, Feb 9/78, 499)
A laser-heterodyne radiometer (LHR) developed by Dr. Robert Menzies of the Jet Propulsion Laboratory had obtained evidence of ozone destruction in the upper atmosphere, JPL reported. The unique instrument, carried on a gondola suspended from a helium-filled polyethylene balloon, had gathered extremely accurate data by "looking" at the sun through the stratosphere during sunset at an altitude of 25km (120 000ft) where ultraviolet light breaks apart carbon molecules, releasing chlorine. Atoms of chlorine normally existed in quantities so small that their presence was difficult to detect; however, scientists had determined the effect of chlorine in destroying ozone, through a chain reaction that would form chlorine monoxide molecules. Later flights would measure the effect of seasonal variations and would look for other molecules responsible for ozone destruction. The research would assist federal regulators investigating danger from fluorocarbons used in refrigeration and air-conditioning; regulators might decide to ban aerosol propellants by June of this yr. (JPL Universe, Feb 17/78, 1)
JSC reported it had begun a new procedure for receiving and processing rare and pristine meteorite samples. Such a program had not been necessary previously because available meteorite fragments had been contaminated by reaction with the soil where they fell, by weather, and by often unsterile handling conditions. The new meteorite facility would contain a near-pristine meteorite collection found in the winter of 1977 near McMurdo Station in Antarctica; the first two meteorite samples were 2()0- to 300-gram (baseball-size) fragments believed by NSF to be rare carbonaceous chondrites that might include primordial matter from the solar system.
Dr. William Cassidy, Univ. of Pittsburgh geologist working under an NSF grant, who had found the samples on an Antarctic ice shelf, had hypothesized that large accumulations of meteorites might exist in areas of the Antarctic, where ancient "blue ice" rose to the surface. Meteorites that fell on Antarctica centuries ago might appear on the surface along with the ice. Although the movement of the ice to the surface was not well understood, within 2 mo (last Dec. and Jan.) Cassidy had found 310 fragments believed to represent between 20 and 50 different meteorites, the most concentrated find known so far. Because of the exceptional preservation possible in the extreme cold and dry environment, Cassidy's find of 310 samples was probably the least contaminated near-pristine meteorite group ever collected. To ensure proper handling, the NSF and NASA's Lunar Curatorial Facility in Houston had equipped Cassidy with special sterile equipment to safeguard his collection.
Researchers at the meteorite-processing facility, using glove boxes first used to handle material from the moon, would document the samples and make initial characterizations before freeze-drying them to remove any trapped water-ice and making a mold, finally storing the samples in dry nitrogen gas. A special committee representing the NSF, the Smithsonian Museum of Natural History, NASA, and Dr. Cassidy's team would plan systematic examination of the samples. (JSC Roundup, Feb 17/78, 1)
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