Word: radar
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Dates: during 1960-1969
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...border. Obacz crammed his wife and two sons, Lester, 9, and Christopher, 5, into the rear seat of a prop-driven, two-seater training plane. Only after they were aloft did he tell them-over the plane's intercom-that he was making a break. To avoid Communist radar detection, he hedgehopped over the ground, never flew higher than 150 ft. throughout the entire 150-mile trip. When one Polish ground station called for his location, Obacz did not reply...
...Danish and Norwegian military men, probably knew a lot about the NATO defenses and weapons. He also knew Swedish defense sites and strengths, had access to key mobilization and communication plans. In Washington, he had access among other things, to detailed information on the U.S. Army's Hawk, radar-guided antiaircraft missile designed to knock down low-flying supersonic planes. The Russians are working hard to perfect a defense against low-level nuclear attack, and the Hawk could help them...
...bomber force proved no match for the R.A.F. reinforced by U.S. planes. In 1942, 1,000 bombers devastated a great part of Cologne in 90 minutes (though the cathedral escaped serious damage). In 1943, 400 bombers were able to do comparable damage to other cities in 15 minutes, since radar allowed them to approach a target at the same time from different heights and directions...
...irregularities contained new knowledge about the target planet. JPL's radar contact measured the distance of Mercury with an error less than 100 miles-an accuracy that is not possible in optical astronomy. It also timed Mercury's slow rotation, which has the same speed as its 88-day orbit around the sun. Most of the results agreed with predictions. But there was one surprising variation: the surface of Mercury proved to be unexpectedly rough. "We're not talking about vast mountains and valleys," says JPL Radio Astronomer Richard Goldstein. "We're talking about something...
...permanently sunlit side is 1,800° F. The roughness of Mercury could be due to any irregularities more than a foot or so in width-large enough to scatter the 5-in. waves of the Goldstone transmitter. If Mercury's surface were smoother than that, the radar waves would be reflected from a small highlight in the center of the disk. Instead, the planet is radar bright all over, which means that its whole surface must have irregularities that bounce radar waves back toward the earth...