NASA Clears Shuttle Discovery for Thursday Launch as Stormy Weather Looms

Shuttle Discovery's Gas Leaks Repaired In Time for Wednesday Launch
The space shuttle Discovery and its STS-133 crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the International Space Station. The launch attempt on Wed., Nov. 3 was delayed, however. (Image credit: NASA/Troy Cryder)

This storywas updated at 7:36 p.m. EDT.

CAPE CANAVERAL, Fla. ? NASA has decided to press on withplans to launch the space shuttle Discovery on its final mission Thursday afterevaluating a last-minute electrical glitch on the spacecraft, but a dismalweather forecast looms ahead.

Teams here at NASA's Kennedy Space Center reviewed the datafrom the anomaly overnight and concluded that the problem was likely the resultof residual contamination on a circuit breaker connection, rather than aproblem with the engine controller itself.

Engineers "scrubbed" the connectors by pluggingthem in and out, which cleans the metallic surfaces of the residue. Missionmanagers are confident the issue has now been resolved.

"We talked overnight, the team brought us a very nice,cohesive flow through the data," Mike Moses, NASA's shuttle integrationmanager, said in a news briefing. "We had a unanimous poll out of the[mission management team], and everyone was very comfortable with the storythat came together today."

Discovery is slated to blast off from a seaside launch pad at Kennedy Space Center at 3:29 p.m. EDT (1929 GMT) tomorrow (Nov. 4).The decision came after an hours-long discussion by top mission managers toclear Discovery of any concerns related to an electrical glitch in a backupmain engine computer controller.

Weather, however, still poses a dire threat for Discovery'slaunch chances. Current forecasts show an 80 percent chance that foul weathercould cause yet another delay, though conditions improve for later attempts onFriday.

Managers will reconvene early tomorrow morning beforetanking to assess the weather situation.

The glitch was detected yesterday and forced NASA to halt launchpreparations for Discovery. The shuttle was initially slated to launchMonday (Nov. 1), but was postponed due to unrelated gas leaks that have sincebeen repaired.[GRAPHIC:NASA's Space Shuttle ? From Top to Bottom]

During the orbiter's engine checkouts yesterday (Nov. 2),the backup controller for Discovery's Main Engine No. 3 did not turn on asexpected. When it powered on about an hour and a half later, engineering teamssubsequently observed an irregular voltage drop.

Discovery is slated to fly an 11-day mission to theInternational Space Station to deliver a new storage module and a humanoidrobot for the orbiting lab's crew. It will be the 39th and last flight for spaceshuttle Discovery, which is the first of NASA's three shuttles to beretired as the agency winds down its orbiter program next year.

If NASA cannot launchDiscovery by Sunday, Nov. 7, it will miss the current window and have tostand down until Dec. 1 to try again.

Follow Staff Writer Denise Chow onTwitter @denisechow asshe covers Discovery's final space voyage from Cape Canaveral, Fla. Click here for missionupdates, new stories and a link to NASA's live webcast coverage.


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Denise Chow
NBC News science writer

Denise Chow is a former staff writer who then worked as assistant managing editor at Live Science before moving to NBC News as a science reporter, where she focuses on general science and climate change. She spent two years with, writing about rocket launches and covering NASA's final three space shuttle missions, before joining the Live Science team in 2013. A Canadian transplant, Denise has a bachelor's degree from the University of Toronto, and a master's degree in journalism from New York University. At NBC News, Denise covers general science and climate change.