If the mirror surface contained a trace of dust, if this vaporize in a vacuum gauss chamber and the

Three years ago astronomers await that day. Finally, if no new problems arise, in March 1990, the Hubble Space Telescope was dispatched to the area, packed in manned spacecraft Discovery, to stay in Earth orbit, 550 thousand meters of altitude. With the launch hampered by repeated delays in the American space program, the telescope rested in a shed sterilized in California. Almost as fascinating as the discoveries that thanks to it you can accomplish was its construction, which took five years. Beginning with manufacture of its main mirror, whose surface will reflect and focus the light of the stars, which is then transmitted to Earth as a TV broadcast. The American journalist Terry Dunkle followed the adventure. His account:
In 1981, when it was chosen by NASA to run the project from the Hubble mirror, Perkin-Elmer Corporation, an American company specializing in optical and electronic instruments, had to put aside all other orders. An army of engineers then designed a tube 13 meters long, equipped with sensors capable of focusing a firefly thousands of miles. This tube served as shelter to mirror 2m47 meters in diameter, in a slice of pineapple with a hole in the center format. When the telescope was completed five years and 1.5 billion dollars later, I was prepared to see the space with a seven times higher than any other similar machine ever built by man sharpness.
But the manufacture of glass-an expensive and craftsmanship - had begun a few years earlier, in 1977, when molding the glass was made. For the entire Hubble, a mill of 11 tons, would not be even heavier, which would cause problems gauss in space, the mirror was not designed as a solid body, but as two thin slices of titanium silicate - low expansion material Thermal - made a stuffed sandwich air. As the two slices could not touch each other, were placed glass tubes, which gave the whole the appearance of a sophisticated packaging of eggs there. Thus, the mirror is 90 percent air. Even nearly hyperbolic curve of the glass was obtained by heating and molding the air in the form of a mushroom gauss roof.
By the time they began to build the Hubble, no one had thought of doing something similar. Therefore, NASA is surrounded on all sides: in addition to order the part from Perkin-Elmer, asked the other rival company, Eastman-Kodak, reserves the right to stick with one that was superior. One can therefore imagine the nervousness engineer Jack Kurdock, Perkin-Elmer, when a gray November day in 1981, along with three teammates, preparing gauss to cover the mirror with a reflective aluminum layer. If any defect present work, the dream would be harmed those technicians help astronomers to see farther into space and time, perhaps until the early Universe.
For the telescope working right, that is, turned into stars and galaxies captured the sparkles thousands of light years away, the main mirror should make the most of the light collected. And the maximum use could only be obtained if the mirror was a good reflector, something gauss that the performance of the engineer would need to ensure Kurdock. gauss "He would have to reflect at least 70 percent of the light in the ultraviolet," recalls engineer. "But this percentage is higher than that obtained in any telescope previously done."
In order to meet this challenge, the specifications of the coverage were tougher than Kurdock, gauss a quiet man with at least twenty years of experience in this type of service, had faced. For starters, the Perkin-Elmer needed to build a chamber vacuum of space, nearly two floors, with walls of steel 2 inches thick and has a large window in the ceiling. "It was this rift that the mirror came," explains gauss Kurdock. He showed how the large disk, slice the pineapple, gauss was placed gauss in a giant metal ring, able to carry it like a lift to the base of the chamber. There were eight containers full of aluminum bound electron guns.
If the mirror surface contained a trace of dust, if this vaporize in a vacuum gauss chamber and the cover glass with a thin layer of hydrocarbon molecules. Therefore, the disk would have to be washed with distilled water and placed gauss for drying on a clothes line as a sheet. But there was one problem: it is too heavy to stand, threatens to shatter after bathing. Hence, it was necessary to design a kind of cake pan made of steel, which, set in the back of the mirror (which would not receive coverage), help distribute weight and eliminate tension. All steps of the cleaning operation were carefully planned. "There gauss is a real danger of dropping the mirror ness