Astronauts aboard the space shuttle
Endeavour took one last look at their spacecraft's heat shield Wednesday to
hunt for any new damage sustained on its marathon flight to the International
Space Station.
Endeavour's seven-astronaut crew
used a sensor-tipped inspection pole to scan the vital heat shield panels
lining nose and wing edges of the spacecraft for any new dings while the
shuttle has been
in space. The shuttle undocked from the station Tuesday and is set to land
in Florida on Friday.
The survey, known at NASA as a late
inspection, is a now-standard part of every shuttle flight to search for damage
caused by micrometeorites
or space junk. It is identical to an inspection performed by Endeavour
astronauts just after their July 15 liftoff to scan for damage caused by launch
debris.
"We do pretty much the exact same
thing on this day to make sure that we haven't had any damage while we're on
orbit from micrometeorites," said Endeavour commander Mark Polansky
in a NASA interview.
Polansky and his crew are headed home to
wrap up a grueling
16-day mission to the space station. During their 11 days linked to the
outpost, the astronauts temporarily boosted the station's population to 13
people while working alongside the outpost's core six-man crew.
Together, the astronauts replaced a
member of the station's crew and performed five challenging spacewalks to
deliver spare parts and new batteries, as well as install a brand new experiment
porch on the outpost's $1 billion Japanese Kibo laboratory.
Wednesday's inspection is expected
to last for about six hours, with engineers on Earth prepared to analyze the
images and data beamed to Earth in order to determine by mid-day Thursday.
While the shuttle astronauts inspect
Endeavour, a new Russian cargo ship arrived at the International Space Station
early Wednesday, though the outpost's commander Gennady Padalka of Russia had
to take remote control of the spacecraft to dock it in a manual mode after its
automated system failed. Padalka eased the spacecraft into a docking berth at
the aft end of the station's Zvezda service module at
7:12 a.m. EDT (1112 GMT).
Endeavour in good health
Engineers have already cleared
Endeavour's heat shield of any concerns related to the more-than-usual amount
of foam insulation that fell from the shuttle's external tank during launch.
Analysis of data from the first
inspection and a photographic survey by station astronauts just before the
shuttle's arrival (also a now-standard chore) found only minor dings in
Endeavour's heat resistant tiles on its starboard wing near the forward
fuselage point. The dings pose no threat to the shuttle or its crew, mission
managers have said.
Annette Hasbrook,
mission operations representative for Endeavour's flight, said engineers are
confident the shuttle is fit for its planned return to Earth.
"We have not tracked anything
unusual that has happened during the joint mission so we expect to see a clean
vehicle when we inspect it," Hasbrook told reporters
in a late Tuesday briefing.
NASA has kept a close watch on
shuttle heat shield health since the tragic 2003 Columbia disaster that killed
seven astronauts. Columbia's heat shield suffered severe damage when a large
piece of fuel tank foam insulation struck its left wing during liftoff. The
damage led to the shuttle's destruction and loss of its crew during re-entry
two weeks later.
Since the Columbia accident, shuttle
astronauts inspect their spacecraft heat shields at least twice every flight,
with station astronauts performing photographic surveys. Extra inspections can
be performed to look at specific areas if warranted (it wasn't for Endeavour)
and astronauts carry repair tools to fix for some types of damage.
Endeavour's space station flight is
NASA's third shuttle mission of the year. The shuttle is due to land at 10:47
a.m. EDT (1447 GMT) Friday at NASA's Kennedy Space Center in Cape Canaveral,
Fla., weather permitting.
SPACE.com is providing continuous
coverage of STS-127 with reporter Clara Moskowitz and senior editor Tariq Malik
in New York. Click here
for mission updates and SPACE.com's live NASA TV video feed.
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