In the late afternoon shadows, space shuttle Atlantis is still poised on the pad after its launch on mission STS-122 was postponed on Dec. 6, 2007.
Credit: NASA/George Shelton.
NASA?s shuttle Atlantis is on track for an early February launch toward the International Space Station (ISS) after two months of delay to repair a suspect fuel tank connector.
Atlantis is slated to launch Feb. 7 on an 11-day mission to deliver the European-built Columbus lab to the ISS, though the final approval for the space shot will be discussed on Wednesday, NASA officials said Friday. The mission has been delayed since early December, when fuel gauge-like engine cutoff (ECO) sensors in Atlantis? fuel tank failed standard countdown checks.
Engineers tracked the problem to a suspect electrical connector at the bottom of Atlantis? 15-story fuel tank. The super-cold temperatures of the shuttle?s cryogenic liquid hydrogen propellant stored in the tank may have led to open circuits in the connector, which has since been replaced with a new, modified design.
?We?re continuing to track toward Feb. 7,? NASA spokesperson Kyle Herring, of the Johnson Space Center in Houston, told SPACE.com late Friday after a shuttle program-level readiness review. ?Everybody has a fairly high degree of confidence in the troubleshooting and testing that?s been done on the ECO sensor connector, and the repair work.?
Shuttle engine cutoff sensors are designed to serve as a backup system to shut down an orbiter?s three main engines before their fuel tank runs dry. If the engines continue to run on an empty tank, they could cause catastrophic damage, NASA officials have said.
NASA?s flight rules call for three of the four sensors to operate properly before attempting a launch, though mission managers tightened the guideline up to four-of-four good sensors on a one-time basis for the second of Atlantis? two launch attempts last month. Shuttle managers plan to return to the standard three-of-four rule for the upcoming February launch, with a final decision to be made during the Wednesday meeting, space agency officials said.
Shuttle workers, meanwhile, have returned to their normal preflight preparations after completing the repair work at NASA?s Kennedy Space Center spaceport in Cape Canaveral, Fla., where Atlantis stands atop its Pad 39A launch pad.
?We?re not dealing with any hardware issues or personnel issues that would stand in the way or hold up the launch,? said KSC spokesperson Allard Beutel, adding that most shuttle work teams are able to take the weekend off in the wake of the fuel tank fix.
While NASA shuttle managers conduct their final review of Atlantis? launch readiness on Wednesday, space station commander Peggy Whitson and flight engineer Dan Tani are expected to step outside the orbital laboratory on a spacewalk to replace a suspect solar array joint motor. NASA officials will discuss the results of both activities during separate briefings on Jan. 30.
Commanded by veteran shuttle flyer Stephen Frick, Atlantis? STS-122 mission will deliver the space station?s Columbus lab for the European Space Agency (ESA) and swap out one member of the outpost?s three-person Expedition 16 crew. The spaceflight is the first of five shuttle flights planned for this year.
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