Word: soho
(lookup in dictionary)
(lookup stats)
Dates: during 1990-1999
Sort By: most recent first
(reverse)
Indeed, the thrusters actually caused SOHO to begin spinning with its two solar panels nearly edge-on to the sun rather than facing it. Without solar energy, SOHO's batteries quickly drained, cutting off power to all its systems...
Again and again, controllers vainly sent signals to where they thought SOHO should be. Weeks went by without a response. Then, in mid-July, a University of Colorado physicist named Alan Kiplinger had an idea. Why not search for SOHO the same way flight controllers look for commercial airliners: with radar? Realizing that extremely powerful radar would be needed to bounce a signal off so distant a target, he called on Donald Campbell, the chief scientist at the world's largest radiotelescope, the 1,000-ft. dish at Arecibo, Puerto Rico. Campbell agreed to try, although he estimated that...
...July 23, Arecibo directed a powerful high-frequency radio beam toward the site SOHO should have been, a million miles away orbiting the sun. Ten seconds later, NASA's 230-ft. radiotelescope at Goldstone, Calif., began picking up its faint radar profile, barely perceptible against the background noise of space...
...SOHO was still close to its proper orbit, wobbling at top and bottom and rotating once a minute, too slow to have caused structural damage. Even more encouraging, the geometry of SOHO's orbit was tilting the craft's axis of rotation toward the sun by about a degree a day. That was gradually increasing the amount of sunlight hitting the solar panels. Ground controllers ordered SOHO to store that intermittent flow of energy and recharge its batteries...
...hadn't the spacecraft responded to controllers' signals before? Perhaps, suggested an ESA scientist, the probing signals were too complex for the weakened SOHO to comprehend. Early in August controllers sent a much simpler message. Result: contact! SOHO responded by transmitting its carrier signal. It was still alive and, as its batteries gradually charged, able to transmit a modicum of data...