Jun 18 1976
From The Space Library
Space News for this day. (1MB PDF)
NASA launched the Gravitational Probe-A (GP-A) from Wallops Flight Center at 7:41 am EDT on a Scout vehicle into a trajectory with peak altitude of 889 km and total flight time of 6960 sec. The 102.5-kg probe was designed to measure the gravitational red shift predicted by the equivalence principle laid down by Einstein in 1907 as the cornerstone of the general theory of relativity: GP-A would directly determine the effect of gravitation on time by comparing the rate of a rocket-borne clock to an identical clock on earth. During the flight, the probe clock would be in a weaker gravitational field than the identical clock on earth; as the probe clock rose through increasingly weaker gravity to its maximum altitude, it would appear to run increasingly faster, and its rate would slow as it returned to the stronger gravity at lower altitudes. The experiment required not only extremely accurate telemetry throughout the probe's ascent and descent, but also an extremely accurate set of clocks; those used were atomic-hydrogen masers of extraordinary stability, according to Dr. R.F.C. Vessot of the Smithsonian Astrophysical Observatory, principal investigator. ("Maser" is an acronym for microwave amplification by stimulated emission of radiation.) The clocks were expected to provide measurement accuracy within 5 thousandths of 1 (5 x 10-) of the predicted effect. The experiment and its support systems performed normally, but Dr. Vessot said that 1 to 3 mo of data reduction would be needed to determine whether the scientific objective had been met. (NASA Release 76-106; MOR S-879-76-01 [prelaunch] 14 June 76, [postlaunch] 23 June 76; MSFC Release 76-113)
A 2-mo study this summer at the Ames Research Center would bring together a specially chosen panel of a dozen scientists-"authorities on every aspect of space exploration"-to make an in-depth examination of problems anticipated in the colonization of space. Sponsored by NASA, the group would also consider whether satellite power stations for earth could be built by space colonists. In a report by James Barron for the Washington Star, Princeton physicist Gerard K. O’Neill detailed his ideas for a kilometer-plus-wide cylinder with living quarters for 10 000 colonists on its outer rim, the length to be determined by the number of colonists desired; O'Neill emphasized that the colony could be ready by 1990 using existing technology and materials mined from outer space. O'Neill last year took his theories to a NASA-sponsored study group at Stanford University that included 28 physicists, engineers, and social scientists; the panel recommended that the U.S. move toward the colonization of space, saying that it "would represent ‘cashing in’ on the scientific information returned to us by Apollo." (W Star, 18 June 76, A-1)
The USSR Venera 10 spacecraft, launched a year ago and in orbit around the planet Venus for the past 8 months, was continuing its research work although its companion, Venera 9, had ceased to function, a Tass broadcast announced. Venus was passing behind the sun "from the point of view of an observer on earth," and a radio beam sent to earth by Venera 10 had passed only 1.5 million km from the sun's surface. Analysis of Venera 10 signals had shown that streams of near-solar plasma were very heterogeneous and subject to rapid changes in time; also studied were the possibilities of receiving information and controlling spacecraft depending on conditions of radio beams passing near the sun. (FBIS, Tass in English, 18 June 76)
18-30 June: Johnson Space Center announced its plan to use a space environment simulation chamber to dry records and documents damaged in Houston's flood 15 June. The first batch, scheduled to be dried 19 June, consisted of medical records from Methodist Hospital and valuable irreplaceable books from the Contemporary Arts Museum, as well as museum records. The material would be put inside the chamber on shelves that would be heated to 48°C, and the chamber would be pumped to a vacuum; the process would take from 48 to 72 hr. The technique was pioneered by McDonnell Douglas Aircraft Corp. for the USAF when the latter's records were water-damaged in a fire. A later announcement said the drying was successful and that JSC was in process of drying material from St. Joseph's Hospital and the Univ. of Houston's law library. (JSC Release 76-42; JSC release 30 June 76)
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