CAPE CANAVERAL, Florida - shuttle to powered NASA discovery platform launch Friday, not for flight, but rather to understand the mysterious cracking tests which will last month.
Discovery is rooted at least at the beginning of the month of February of potentially dangerous cracks appear in the tank of fuel to an actual launch attempt. Cracks have been fixed, but the engineers do not always understand why they occurred.
If a test countdown has started shortly after the Sunrise, team launch pumped more than 500,000 litres of liquid hydrogen and oxygen in the fuel tank externally the discovery. The tank was rigged with close to 100 gauges of strain and temperature sensors to provide clues on cracking and thousands of feet of wire for recording devices.
That discovery flying, it will be his last trip into orbit and the final two or three shuttle missions remaining. He is responsible for supplies to the international space station as well as experimental humanoid robot.
"We do sums not committing theft anytime soon." "We have achieved to wait until we know that a good answer to fly," said Mike Moses, a manager of launch, as the 15 floors discovery tank filled. "We want to make sure that we know the potential that we have before us."
Back on November 5, NASA interrupted the countdown for the discovery of Leaker of hydrogen gas. A non-related problem - cracking - later was discovered in fuel tank foam insulation in ribbed central holding instruments. When the foam has been deleted, cracks were found in two of more than a hundred of aluminium ribs or brackets that make up this region. Damaged both coasts-21 foot long each - were next to each other.
Both flight and cracks were fixed and NASA to flight in December as possible. But engineers were blocked in which caused the cracks. They think now there were a build-up of stress in brackets to the Assembly, which caused cracks when super cold fuel has been loaded into the reservoir, said Moses.
"We are 100 times smarter we were a week ago and we are 1000 times smarter that we where the failure happened first," said Moses. "We will not likely to come here with a smoking gun." But we are going to come here with a family of chess.
There is concern that cracks in the brackets may cause pieces of pop foam and in the worst case, snapping the discovery take-off. A large plate damaged foam Columbia launch in 2003 and has led to its destruction during re-entry.
Also the rope cables with sensors on the suspicious part of the tank and gauges, also painted technicians from small black dots - 10 000 to 12 000 of them - on the white foam exposed above the repaired area. Moses called finger painting and it is the case. technicians worked in temperatures, their fingers gloved in paint dipping and then pressing on their gently on the foam. Twice more points were painted on another section at the rear of the tank.
Points were part of a test of optics. A pair of cameras aimed at them for stereoscopic views. The intention was to record the movements of the tank in this area and provide additional clues on cracking.
In total, NASA plans gather 6 terabytes of data to test on Friday. The information will be analyzed in the next week.
Discovery, meanwhile, will be returned to the Assembly building vehicle week next to engineers of x-ray hooks at the rear of the fuel tank. These areas are inaccessible to the launch pad.
The objective is to launch as early as February 3 discovery or at least by the end of the month, said Moses.
NASA's shuttle program is set to retire after 30 years of flight next year. Space shuttle Endeavour is due to fly in April, and Atlantis may follow in the summer if financing is to come.
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Online:
NASA: http://www.nasa.gov/mission_pages/shuttle/main/index.html
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