Sep 13 1976
From The Space Library
A select committee of the National Academy of Sciences, named 2 yr ago at the request of four federal agencies, recommended a 2-yr delay before banning aerosol sprays containing fluorocarbons. The group advised three "urgent" measures: drafting of legislation to regulate fluorocarbon usage when the need arose; action to require labeling of products containing fluorocarbons, so that consumers could stop using them if they wished to do so; and a campaign by public health agencies to reduce people's overexposure to sun and the resulting malignant melanoma, incidence of which had been increasing by 10 to 15% a year, about a third of the current 8500 yearly cases being fatal.
An international conference on threats to the stratospheric ozone, meeting at the State Univ. of Utah, heard Dr. James C. Anderson of the Univ. of Mich. report findings from a 28 July balloon flight of chlorine and chlorine monoxide at 35- to 42-km altitudes in quantities twice as abundant as predicted by theorists. The results had not been available when the NAS findings were issued. The NAS had said that a selective ban on fluorocarbon spray-can propellants would be necessary within 2 yr. The international conference also heard a report that nitrous oxide in the air was increasing steadily as a result of many factors (including fuel combustion and bacterial digestion of fertilizers), 'becoming as serious a threat to the stratospheric ozone as the Freons, with a 20% ozone reduction possible by the end of the 20th century. Bags of exhaust gases obtained from a federal test center for auto emissions had shown that the catalytic converters designed to remove hydrocarbons from exhaust had permitted considerable release of nitrous oxides, Dr. R. J. Cicerone of the Univ. of Mich. had estimated that automobile contribution of nitrous oxide to the atmosphere within a yr was about a million tons.
Researchers from the Univ. of Calif. Livermore Laboratory at Lawrence had told a meeting of the American Chemical Society that better methods of analysis were needed to permit accurate predictions of the effects of contaminants on the stratospheric ozone. Supersonic transport operations, for instance, were known to affect the stratosphere but not enough was known about the forty-odd possible chemical reactions at high altitude to say if or how the ozone layer was damaged. William H. Newer, a chemist on the Livermore team, added that, even if all the chemistry were pinned down, the effect of SST operations could not be determined precisely until meteorological factors were fully accounted for. The next 1 or 2 yr should provide new insights into these stratospheric processes, the team said. (NYT, 14 Sept 76, 1; 17 Sept 76, A14; W Post, 14 Sept 76, A-1; Av Wk, 6 Sept 76, 49)
13-16 September. The soil-collecting arm of the Viking 2 lander apparently jammed some time between delivering a sample of Mars soil to the biology-experiment hopper on Sunday and delivering the rest of the soil to a second hopper leading to an x-ray analysis chamber. The first indication of trouble came when a routine picture transmission of the sampling sequence failed to show the collector head, although another picture showed that the collector had dug a trench and collected a soil sample. The lander had been programmed to halt the arm motion if something went wrong; Project Manager James S. Martin, Jr., said more than a day might be needed to define the problem. (The arm on the Viking 1 lander had jammed twice while digging at Chryse, and both times the flight directors at JPL were able to get it moving again.) A command would be sent to the Viking 2 lander Tuesday morning, 14 Sept., to extend the arm from its arrested position to be photographed so the flight directors could see what went wrong. The halt in operations meant that the gaschromatograph spectrometer intended to analyze the soil for organic molecules never got a sample for analysis.
The biology experiments, which did receive soil samples, were progressing with their tasks. The gas-exchange experiment had already indicated a slower response to oxygen leaving the soil in its test chamber than was shown by a similar Viking 1 instrument at Chryse, where a high oxygen count had been considered a possible indication of life activity. Scientists had decided the reading probably resulted from "an exotic chemistry." Dr. Harold P. Klein, chief biologist on the project, said the lower readings at Utopia might simply indicate "less oxidizing substances at the Viking 2 site." The other two biology instruments were incubating their soil samples; both were transmitting data on background radiation for use as reference points later in the experiments, which would use radioactive counts to determine the presence of microorganisms.
After seeing a picture of the lander's arm, showing that it had rotated 180° instead of 45° as it should have, flight directors diagnosed the problem as failure of a switch. Project Manager Martin said it would be possible to override the switch and get the arm moving again by Friday, 17 Sept., when flight directors would order the arm to continue delivery of a soil sample to the x-ray instrument.
At a news conference 16 Sept., project scientists reported that the first measurements from the labeled-release experiment showed 33% more radioactive gas count from the Utopia sample than had come from the Chryse soil: 10 000 counts per minute (compared to 7500) or 20 times the amount of gas that would be registered in the absence of metabolic activity. The scientists still refused to say the activity was proof of life, noting that, if organisms were picking up all the nutrients in the instrument, it should record up to 15 000 counts per minute. The gas-exchange experiment, which had detected some signs of activity in the Utopia sample but less than Viking 1 found in the Chryse sample, apparently provided an argument against the "exotic chemistry" theory because of the prolonged increase of carbon dioxide in the test chamber. Dr. Vance 1. Oyama of Ames Research Center said of this result, which might be attributed to chemical reaction, "if it persisted and was accompanied by other changes, we can ascribe it to biological changes." No decisive report had come from the pyrolytic-release experiment, considered the least ambiguous of the detectors.
Project geologists meanwhile were scanning the photographs from both Viking orbiters and landers, noting especially the enormous scale of Martian topography. "Everything we see is ten times anything on earth," said Dr, John Guest of the Univ. of London, adding that earth in comparison was almost as smooth as a billiard ball. Most prominent features on Mars were the volcano Olympus Mons whose base on earth would reach from New York City to Montreal, and a canyon long enough to stretch from New York to Salt Lake City. The plateau on which the Mars volcano rested stood more than 9 km high, taller than Everest, earth's highest mountain. Dr. Michael Carr of the U.S. Geological Survey suggested that the outsize features of Mars existed because of the lack of plate movement on the planet. Mars, like earth, appeared divided into two "provinces" geologically, one area heavily cratered and higher, therefore assumed to be older; the other area was lower and smoother, considered to be younger. This division might be typical of all bodies of the inner solar system, as a similar distribution of "provinces" appeared on the moon and on earth. (W Star, 13 Sept 76, A-5; 15 Sept 76, A-2; W Post, 14 Sept 76, A-12; 16 Sept 76, C-1; 17 Sept 76, A-4; NYT, 17 Sept 76, A14; C Trib, 18 Sept 76, 1-7)
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