Word: spacecrafts
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Dates: during 1960-1969
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...moon is also a natural, orbiting Cape Kennedy. To blast off, a spacecraft need overcome a pull of gravity only one-sixth as strong as the earth's, and does not have to expend any energy to push through a thick atmosphere...
...past five years, man has used the sophisticated instruments of the space age to learn more about the moon than he did during the 360 years that followed Galileo's pioneering look at the lunar surface through a telescope in 1609: Unmanned spacecraft have crashed into the moon, orbited it, measured it, and photographed it from every conceivable angle, giving man his first view of the lunar far side. Ingenious soft-landing spacecraft have dug into its soil and even chemically analyzed it by remote control...
Lunar gravity is relatively so weak, as a matter of fact, that some scientists have suggested launching spacecraft by simply accelerating them with electrical power along a track. Unimpeded by atmospheric friction, the vehicles could accelerate very rapidly, limited only by the maximum gravity that their cargo could withstand. An unmanned craft designed to take a force of 50 G's, for example, could reach escape velocity on a track only four miles long. Manned ships, whose passengers could not be exposed to so high a G-force, would need a track considerably longer...
...plummeted uncontrollably toward earth when the rocket engine in his X-15 failed to start, but it caught on just in time. As commander of Gemini 8 in 1966, he had to abort the scheduled three-day flight after ten hours when a short circuit threw the spacecraft's thrusters out of control. Last summer he had to eject from a lunar-landing research vehicle at an altitude of only 100 ft. when it spun out of control and crashed...
...responsibility were crucial factors in the U.S. effort to land men on the moon, so were the contributions made by a number of individuals. By providing the answers to such questions as how to build a big enough booster, what flight plan to follow, and how to guide the spacecraft, these men eliminated obstacles that might have delayed the program indefinitely. Among...