A knob
wedged against a cockpit window in shuttle Atlantis was freed, NASA said
Tuesday, giving engineers a chance to look more closely at any damage it
caused.
It's not yet clear if the
window's nicked pressure pane, the innermost of three panes, might need
to be replaced.
That could require a
difficult and time-consuming procedure that historically was only done when
orbiters were grounded for periods of extended maintenance in California.
"We're used to
swapping the outside panes after every flight," said Kyle Herring, a NASA
spokesman. "The inner pane is typically not changed."
He said it was too soon to
say whether the unusual problem could impact a targeted
Nov. 12 liftoff for Atlantis on a mission to deliver spare parts to the
International Space Station.
The notched steel rotary
knob, used to fasten a work light to a bracket, wedged itself between the
shuttle's dashboard and one of six forward windows during the final mission to repair
the Hubble Space Telescope in May.
NASA was worried that some
removal techniques, potentially including taking apart the dashboard, could
cause more serious damage to the window.
Technicians' attempts at
Kennedy Space Center to loosen the crescent-shaped knob using dry ice failed.
But it was freed Monday
night after technicians pressurized Atlantis' crew cabin, causing it to expand
slightly and ease the knob's grip.
The knob was first chilled
with liquid nitrogen and showed some movement. It came loose minutes after the
cabin pressure was raised to more than 17 pounds per square inch.
The standard cabin pressure
during flight is 14.7 psi, or roughly sea level. The pressure was lowered to
10.2 psi during five back-to-back spacewalks to install new instruments on
Hubble and repair damaged ones.
Atlantis has two more
scheduled flights before NASA plans to retire
its fleet of three space shuttle orbiters late next year, after a total of
eight more flights.
The window problem sparked
speculation that NASA could decide to mothball Atlantis early rather that put
it through an extended repair process, a possibility agency officials have
downplayed.
"It's probably way too
premature to say what the ramifications are now that the knob has been
removed," Herring said.
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