Aug 23 1978
From The Space Library
NASA announced that two radio astronomers at the Jet Propulsion Laboratory had discovered major changes deep in the atmosphere of Uranus. Dr. M.J. Klein of JPL and Dr. J.A. Turegano, a visiting research associate from the Univ. of Zaragoza, Spain, found that radio emissions from Uranus had become 30% stronger over the past 10yr. Klein and Turegano, who had used NASA's 64m (210ft) radio antenna at Goldstone, Calif., explained that radio waves emanating from dense clouds on Uranus had originated deep in the atmosphere, where pressures might be more than 10 times greater than at earth's-surface.
Observations in the spring of 1978 had confirmed the two astronomers' discovery a yr earlier; the atmosphere of Uranus could be either warming or becoming clearer to the passage of radio waves, although the investigators doubted that temperature so deep in a planet's atmosphere could warm more than 30% in only 10yr. They thought the change was more probably caused by the planet's unique orientation: Uranus, unlike any other planet, spun on its side as it orbited the sun, and every 84yr (the length of one Uranus yr) the sun would shine directly on the North Pole. Forty-two yr later, the northern hemisphere would be dark with the South Pole pointed sunward.
Ammonia gas in the planet's atmosphere probably blocked radio emissions from Uranus's deep interior. The scientists suggested that ammonia might have been preferentially depleted in the planet's polar regions, either by convection currents or chemical reactions. If so, then the radio telescopes would be registering hotter temperatures deeper in the atmosphere than those recorded 10yr previously when the planet had a different orientation to the sun. Theoretical studies to discover the relationship of the radio measurements to global changes in Uranus's climate, weather patterns, and atmospheric chemistry would help in drawing general conclusions about planetary atmospheres applicable in turn to specific studies of earth's atmosphere. (NASA Release 78-130)
ESA and INTELSAT had prepared a joint offer of Marecs (formerly Marots) satellites, plus maritime packages on INTELSAT V comsats, for an international joint-venture attempt to set up a pre-Inmarsat maritime communications system for the early 1980s, Aerospace Daily reported. The joint venture of Europe's 17-nation Eutelsat group and other countries, including Japan and the Soviet Union, had accounted for about 74% of Inmarsat shares. The U.S., with 17%, had not participated.
At its July meeting, the joint group indicated preference for a space system consisting of three Marecs satellites dedicated to maritime communications, plus maritime packages to be added to the last three of the seven planned INTELSAT Vs. If costs or other factors made the option unsatisfactory, the joint venture had two others: a four-Marecs system, or a combination of two dedicated INTELSAT spacecraft and three INTELSAT V maritime packages. (An option using four dedicated INTELSAT satellites was no longer under consideration.) INTELSAT's board of governors at its mid-Sept. meeting would decide on pricing and other details, and the joint venture would receive the ESA-INTELSAT proposals at its late September meeting. (AID, Aug 23/78, 234)
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