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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