This
story as updated at 5:47 p.m. EDT.
Astronauts
aboard the space shuttle Discovery gave their spacecraft's heat shield a final
health check on Thursday to search for any dings from space junk.
Shuttle
commander Lee Archambault and his crew scanned the spacecraft for any new
damage caused by micrometeorites or orbital debris as they prepare for a
planned Saturday landing to end
a landmark mission that boosted the International Space Station to full
power.
"To the
untrained eye, it looked very, very clean," shuttle flight director Paul Dye
said as the inspection ended.
Space
debris has been a growing concern of late, with Archambault using Discovery's
thrusters to help move
the space station clear of a piece of orbital junk earlier this week. It
was the third debris event in two weeks for the station, one of which sent
its three-astronaut crew to take shelter in its docked Soyuz lifeboat when
a piece of space trash zoomed close by without enough warning to move the
outpost.
"It's part
of the business," NASA deputy shuttle program manager LeRoy Cain said of space
debris last week. "It comes with the territory and we'll continue to do
whatever is necessary to avoid debris where and when we know about it."
Cain said
the recent spate of space
debris events, which were brought to the forefront by a Feb. 10 crash
between two satellites, are random occurrences. Archambault, too, has said the
recent events were likely just by chance.
"We have
had a couple of these in the last couple of weeks, but as a far as I know it's
coincidental that we've had just a couple in this close timeframe," Archambault
told reporters earlier this week.
Discovery undocked
from the space station Wednesday after eight days of construction work
install the outpost's last set of solar wings. The shuttle beamed back the
first views of the space station with all four of its solar arrays, two per
side, as it backed away from the station and began the trip home.
"It really
was spectacular," a shuttle astronaut radioed Mission Control last night.
Heat
shield check
In their
inspection today, the shuttle's seven-astronaut crew used cameras and laser
sensors at the tip of Discovery's 50-foot (15-meter) inspection boom to scan
the heat-resistant panels lining its wing edges and nose cap. The survey, a
now-standard late heat shield inspection, is identical to one performed by the
astronauts just after launch.
Discovery's
heat shield has already received a clean bill of health with respect to launch
debris from its March 15 liftoff. A small ding near the aft on a left wing
elevon is the most notable damage, but not a threat to the shuttle or its
astronaut crew, mission managers have said.
Thursday's
survey is designed to search for new damage cause by tiny space rocks or other
debris while Discovery was docked the space station.
NASA has
kept a close watch on the integrity of its shuttle heat shields since the
tragic 2003 loss of the shuttle Columbia and its astronaut crew during
re-entry. A piece of fuel tank debris damaged that shuttle's left wing during
launch, leading to its destruction during re-entry.
Discovery's
heat shield, by comparison, appears to be in extremely fine shape. Engineers
will study the data and images from today's survey before clearing the shuttle
for its planned Saturday landing at the Kennedy Space Center in Cape Canaveral,
Fla.
Discovery
is completing a 13-day mission to the International Space Station, where
shuttle astronauts performed three spacewalks to install the new solar wings.
They also helped repair the station's urine recycler and replaced one member of
the outpost's crew - NASA astronaut Sandra Magnus - with Japanese astronaut
Koichi Wakata.
Wakata is
Japan's first long-term resident of the space station and due to return to
Earth in three months. Magnus will complete a 4 1/2-month mission to station
when she returns with Discovery's crew on Saturday.
Discovery
left the space station one day before the launch of a Russian Soyuz spacecraft
carrying the outpost's new crew and the world's first repeat space tourist -
American billionaire Charles Simonyi. Simonyi is paying about $35 million for
his second trip to the station in two years in a deal brokered with Russia's
Federal Space Agency by the Virginia-based firm Space Adventures.
The
Soyuz lifted off on time at 7:49 a.m. EDT (1149 GMT) from the Central Asian
spaceport of Baikonur Cosmodrome in Kazakhstan. It is due to arrive at the
station on Saturday at 9:14 a.m. EDT (1314 GMT), a few hours before Discovery
is slated to land in Florida.
SPACE.com
is providing continuous coverage of STS-119 and Charles Simonyi's with reporter
Clara Moskowitz and senior editor Tariq Malik in New York. Click here for shuttle
mission updates and SPACE.com's live NASA TV video feed.
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