Word: spacecrafts
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...most daring deep-space missions NASA has ever planned is turning out to be one of the least publicized. The target is a large asteroid named 1992KD, which orbits the sun millions of miles from Earth. But that destination is almost incidental to the performance of the spacecraft that will make the trip. Though it looks little different from countless other unmanned probes NASA has launched, the ship will be navigated by an electronic brain that has been likened to HAL, the independent-minded computer in the film 2001, and will move through space under power of a system that...
...goes as planned, Deep Space 1, scheduled for launch later this month, will be the forerunner of a new generation of spacecraft. While flight planners hope the ship will make some interesting observations about the target asteroid, including its composition and the structure of its surface, DS1's prime assignment is to validate a host of new technologies NASA had always considered too risky to try on a high-profile mission. Says Marc Rayman of Jet Propulsion Laboratory, DS1's chief engineer: "We have an unproven propulsion system, powered by an unproven solar array, commanded by an unproven navigation system...
What is most remarkable about the spacecraft is how it gets from place to place. After being launched by an ordinary rocket, DS1 will be pushed through space by an engine that works by firing electrons into atoms of xenon gas, stripping each of an electron and giving the atoms an electric charge--ionizing them. The ions are then accelerated through an electric field and emitted from thrusters at 65,000 m.p.h. Despite that speed, the particles produce little thrust, comparable to the weight of a piece of paper...
Just as innovative is DS1's navigation system. By scanning stars and asteroids, the spacecraft will know precisely where it is and will make its own maneuvers, perhaps even during its asteroid rendezvous. Programmed to fly six miles above the giant rock, DS1 will also have the option of swooping down to half that altitude...
...they were either the pulverized remains of a small moon that had been destroyed by a collision or the raw material of an incipient moon that had never had the gravitational muscle to pull itself together. Last week they reached a different conclusion. New images returned by the Galileo spacecraft reveal that the fairy-dust bands are debris blasted into space when the planet's four innermost moons were struck by meteors...