Word: orbits
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Dates: during 1980-1989
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Rockets, which are also driven by exploding chemicals, can exceed these sonic limits because the combustion takes place in the projectile itself. But rockets also operate under handicaps. So large are the fuel requirements for reaching orbital speed of 8 km (5 miles) per sec. that no one has yet been able to place a payload into orbit totaling more than 1% of the weight of the vehicle on the ground...
...back to the birth of the solar system 4.6 billion years ago, these moons emerged as distinctive and different, showing scars from the millennial pounding of meteorites and possibly comets, as well as cracks from their own version of earthquakes. One pair of little moons travel in the same orbit within the rings of Saturn. They look like broken teeth and may be remains of some relatively recent cosmic carnage: two halves of a larger satellite that split apart in collision with another celestial body...
...only planetary probe now on the drawing boards at J.P.L. is Project Galileo, a scheme to place in orbit around Jupiter a semipermanent observatory. Scheduled for launch in 1984, Galileo is likely to be delayed. Its launch vehicle is the space shuttle. But that much troubled enterprise, plagued by engine problems and difficulties with its crucial heat-shielding, may not make its first orbital test flight before next summer...
...shuttle's problems are also a source of grief to planners of another major scientific effort: the placing in orbit around earth of a ten-ton, 96-in. space telescope. Scanning the heavens above the obscuring atmosphere, and radioing back its findings, the robot telescope could greatly extend astronomy's observable universe, allowing stargazers to see farther and deeper into space. The telescope might even be able to pick out the faint traces of planets orbiting nearby stars...
...could lose ground-especially in relation to the U.S.S.R., which space experts, like military men, are concerned about. Although the Soviets have not fared well in their unmanned explorations, except for landings on Venus, they are surpassing the U.S. in manned space projects. By launching men into orbit every few months, they have accumulated nearly twice as many man-hours in earth orbit as the U.S. Warns Senator Harrison Schmitt, a geologist and former astronaut soon to become chairman of the Senate's space subcommittee: "The Russians are ahead on the knowledge of how people can perform in space...