Learn about the servicing mission of the Hubble Space Telescope.
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The Hubble Space Telescope Maintenance 2/3 A few minor problems helped to count for the length of the space walk. One of the old gyroscope containing rate sensor units was a tight fit in the box design to protect it on its return to earth. There eventually, it was placed inside and the lid closed. Another involved opening valves in removing caps on the near infrared camera and multi-object spectrometer in preparation for restoring it to operation during the next Hubble servicing mission. That task too was eventually completed. All in all, flight and telescope controllers were delighted with the accomplishments of the day. The Hubble Space Telescope was now essentially back in business. Major tasks on the next space walk to be undertaken by Michael Foale and Claude Nicolai will include replacement of Hubble’s outmoded DF-224 computer with a more modern unit, 20 times faster and with six times the memory. They also will replace one of Hubble’s three fine guidance sensors used to precisely point the telescope and gather scientific data. The astronauts also may perform get-ahead tasks. Some which were first scheduled for fourth-plan space walk. However, that space walk was cancelled because of delays in Discovery’s launch. By the end of the fourth day in space for mission STS-103, Discovery remains in excellent condition, in an orbit with a high point of 380 miles and a low point of 369 miles. The seven men in the crew began work early the following day, preparing for a busy day in orbit including a second space walk and a final check of hardware install on the Hubble Space Telescope during the previous day of space walk. This morning’s wakeup music honored the two space walking astronauts Mike Foale and European Space Agency astronaut Claude Nicolai. Traditional Swiss music was played for Nicolai and the song “Only When I Sleep” by The Corrs was played for Foale. The primary goal of the second EVA will be to install a new computer to replace the one currently in use by Hubble. The new computer as we mentioned before is 20 times faster and is six times the memory of the outdated unit being replaced. Nicolai and Foale will also change one of Hubble’s three fine guidance sensors that are used to precisely point the telescope as it conduct scientific observations. The unit being installed is a refurbished one that was removed and returned to earth by the STS-82 crew during it servicing of the telescope in February of 1997. If time permits, the space walkers may also perform some optional get-ahead tasks. Foale has conducted two previous space walks during the STS-63 mission in February 995 and again in September 1997. As he and Mir Space Station Commander Anatoly Solovyev conducted a six-hour survey of the Mir. This will be Nicolai’s first space walk. It's scheduled to begin at 1:50 PM but could begin earlier if the crew members complete their preparations ahead of schedule. Once outside the space shuttle, Foale could be recognized by the broken red stripes on the legs of his EVA suit and Nicolai by the diagonally broken red stripes on his suit. The astronauts installed a new advanced computer during an eight-hour, 10-minute space walk; the third longest in history. Foale and Nicolai also completed the replacement of a 550-pound fine guidance sensor. As well, they supported a functional test of the voltage temperature improvement kits referred to as VIKs, installed by Steve Smith and John Grunsfeld during their space walk on the previous day. Flight controllers reported that all major activities of the space walk, the second of three had been accomplished. More importantly, the controllers reported that power was reaching both of the new pieces of equipment. “The brains of Hubble have been replaced” said mission specialist John Grunsfeld who worked in Discovery’s cabin with the space walking crew members outside. About 30 minutes later, Hubble began thinking with those new brains. At an evening mission status briefing, John Campbell,

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