Word: venusians
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Grand Tour in Space. Beyond this "minimal" program, the scientists say, there are other planetary opportunities that the U.S. should grasp. In 1973 and 1975, for example, the planets will be positioned so that a Mariner flying past Venus will be whipped by Venusian gravity into a trajectory that will carry it close to Mercury, affording man his first glimpse of the sun's nearest neighbor. And in 1977 and 1978, planetary positions will enable a spacecraft flying by Jupiter to take a gravity-boosted "grand tour" that will also take it on past Saturn, Uranus and Neptune...
Though it is the brightest planet in the heavens, Venus has always been less than clear to astronomers. Wrapped in dense clouds of gases, the Venusian surface remains hidden even to the most powerful optical telescopes. Now, scientists are employing electronic means to explore the mysteries of the earth's sister planet. Using radio beams, Radar Astronomers Richard M. Goldstein and Shalhav Zohar of Caltech's Jet Pro pulsion Laboratory reported last week that they have mapped 160,000 sq. mi. of Venus, an area about equal to the size of the entire U.S. Northeast...
...findings, released last week, agree generally with data sent back by Russia's Venus 4 and its landing capsule. Neither spacecraft found evidence of Van Allen-like radiation belts around Venus, both reported hydrogen coronas and found that carbon dioxide was the principal constituent of the Venusian atmosphere. Mariner's finding that the atmosphere was "at least" 7 to 8 times as dense as the earth's does not contradict more precise Russian data showing densities 15 to 22 times as great...
...there were differences in results. Although the Russians did not detect a Venusian magnetic field, Mariner discovered slight magnetic activity that could have come either from a field less than 1/300th the strength of earth's or simply from the interaction between the solar wind and the Venusian ionosphere. The Russians at first reported that carbon dioxide comprised 98% of the Venusian atmosphere, but later revised the figure down to between 90% and 95%, closer to Mariner's reported 72% to 87%. And while Mariner could find no evidence of oxygen in the atmosphere, the Venus 4 capsule...
High Threshold. The Russians also came to the rescue of U.S. scientists, who had been at a loss to explain preliminary Venus 4 reports that there was no nitrogen in the Venusian atmosphere (nitrogen accounts for 78% of terrestrial air). Backing off slightly, the Soviet scientists explained that the nitrogen-gas analyzer aboard the capsule had a "signal-detection threshold" of 7%; thus it would have been unable to detect smaller percentages...