![]() ![]() Shuttle technicians have repaired similar cracks on external tanks by removing the fractured aluminum and replacing it with a twice-as-thick stringer section, before replacing the foam. It's a known failure method."Įngineers are now evaluating images of the cracks to determine the best repair options that can be performed with Discovery remaining at her seaside launch pad at Kennedy Space Center. "They understand the stresses that go on at cryogenic temperature levels while loading the tank. "Even though the foam didn't come off, the crack underneath propagated up, so the cracks in stringer led to the crack in the foam above it," Beutel explained. The cracks in the stringer likely pushed the metal outward to sufficiently dislocate the foam, NASA officials said. The fractures were found underneath the area of cracked foam, and early analysis suggests they were the root cause of the foam damage. The two 9-inch (23-cm) cracks were located at a site called the "stringer," which is an aluminum strip that provides structural integrity to a part of the fuel tank known as the intertank - the partition between the liquid oxygen and liquid hydrogen tanks. 10) on a section of the tank's aluminum skin. While removing the cracked foam layer that covers the tank, two new fractures were found yesterday (Nov. 12), Beutel said.Įngineers also removed damaged foam insulation on Discovery's external tank that cracked during initial loading operations for the shuttle's most recent launch attempt on Nov. This is very different."īased on early evaluations, the team should be ready to install a new flight seal and umbilical carrier plate tomorrow (Nov. "Last year the issue was a slight misalignment of the whole carrier plate. "They found that the flight seal was not properly aligned when they opened up the GUCP," Beutel told. This could account for why the leak cropped up earlier in the tanking process, and leaked significantly greater amounts of hydrogen, than the two previous events, NASA spokesman Allard Beutel said. Both of these were caused by slight misalignments of the carrier plate itself, but this new leak was caused by a different issue - a misalignment of the flight seal inside the ground umbilical carrier plate. Similar leaks have occurred during launch preparations for two previous shuttle missions, both in 2009. Data collected from the initial inspections will be evaluated today. NASA technicians worked overnight to remove the component, and initial inspections were performed on the faulty seal and its corresponding connector before they were sent to labs for more thorough examinations. You can follow Staff Writer Denise Chow onTwitter. SpaceShuttle Discovery's Retirement Plan in Limbo.Video? Space Shuttle Discovery: A Retrospective, Part2, Part3.Gallery:Building Space Shuttle Discovery.It's all about when the data supports a launch." "They're not being pressured by theschedule. "It's not a clear cut process, but management is makingsmart decisions," Beutel said. Still, Beutel emphasized that there are a lot of variablesthat could influence the decision-making process, and ultimately, the nextlaunch attempt will be set when managers are fully confident they understandwhat caused the problems with the shuttle's external tank. NASA is hoping to launch an additional shuttle flightaround June, but is still awaiting final funding approval from a congressionalappropriations committee. ![]() The mission will be the 39th and last flight for Discoveryand is one of NASA's two final scheduled shuttle flights before the orbiterfleet is retired in 2011. The shuttle'splanned 11-day mission will deliver a storage room and Robonaut2, a humanoid robot, to the International Space Station. Īt the end of this month, the computers onboard the shuttleneed to be reconfigured to reflect the year change, and typically, NASA haspreferred to do this while the shuttle is safely on the ground or docked to thespace station.ĭiscovery's STS-133 mission has already been delayed sinceearly November due to technical and weather-related issues. With some coordination, shuttle managers may beable to extend the December launch window, Beutel said, but would want to avoidhaving the orbiter in flight over the transition into the new year. The mid-December launch window for Discovery opens on Dec.17 and runs through Dec. NASA has a short window in which to try and launch Discoverythis month. 17 liftoff, but that's really just thefirst available launch opportunity." "Here at Kennedy, we're doingthings to maintain Discovery'slaunch readiness to support a Dec. "We really don't have a new target launch yet ? we havenot had one since Nov. ![]()
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