Astronauts
aboard the space shuttle Endeavour successfully deployed two sets of tiny
satellites Thursday as they received word they were cleared to come home.
The seven
astronauts aboard Endeavour jettisoned the two satellite experiments to demonstrate new
technology and study Earth's atmosphere Thursday as they gear up for a planned
mid-morning landing in Florida tomorrow. Engineers also gave the shuttle's heat
shield a clean bill of health today, setting the stage for the
Friday landing, Mission Control said.
"Well thank
you Houston, that's good news," Endeavour skipper Mark Polansky radioed back. "We're
looking forward to trying to come back tomorrow."
Polansky
and his crew are returning to Earth to wrap up a grueling 16-day construction
flight to the International Space Station. Endeavour astronauts replaced one member
of the station's crew and performed five complex spacewalks to deliver spare
parts and install a new
experiment porch on Japan's Kibo giant lab during their 11 days docked at
the orbital outpost.
"Frankly, I
do think it's time to come back," Polansky told the Associated Press Thursday.
Endeavour
is also ferrying Japanese astronaut Koichi Wakata back to Earth to end what,
for him, will be a 4 1/2-month mission in orbit. Wakata arrived at the space
station in March on a different space shuttle and is Japan's first long-term
resident at the orbiting lab. He watched over Japan's $1 billion Kibo lab and
performed some unconventional
experiments during the flight before being replaced by NASA astronaut Tim
Kopra, who arrived on Endeavour.
Landing
day ahead
Polansky
and his crew are slated to land at 10:48 a.m. EDT (1448 GMT) at NASA's Kennedy
Space Center in Florida to end their marathon mission to the station. NASA
flight director Bryan Lunney said the weather looks promising for landing,
though there is a chance of rain and thunderstorms within 30 miles of the
shuttle runway.
"I'm really
optimistic things are going to play out well," Lunney said.
Polansky
and shuttle pilot Doug Hurley tested Endeavour's flight control surfaces and
thrusters to prepare for tomorrow's landing. One thruster failed to fire, but
will not be needed during re-entry.
The
first of the two satellite experiments deployed Thursday was DRAGONsat, a pair of small satellites that launched from Endeavour's payload bay as part of a study to demonstrate autonomous rendezvous and
docking technologies, as well as global positioning systems. The satellites
were built by students at the University of Texas at Austin and Texas A&M
University.
Later, the
astronauts jettisoned two perfect spheres that make up the Naval Research
Laboratory's ANDE 2 mission. The two spheres are each 19 inches across, but
have different masses. By watching differences in their orbits, researchers will
study the density of Earth's atmosphere.
Astronauts
repair station air purifier
While
Endeavour's astronauts prepared for landing, the six-man crew of the International
Space Station tackled another glitch with an air-scrubbing device in
NASA's Destiny laboratory.
Called the
Carbon Dioxide Removal Assembly (CDRA), the air-scrubbing device broke down
late Wednesday - just a few days after engineers revived it on Sunday following
an earlier glitch.
A short
circuit in one of the device's 12 heater pads appeared to be at fault, mission
managers said. Station astronauts spent much of Thursday repairing the
air scrubber, which is one of two used to clean carbon dioxide out of the
station's atmosphere.
"We're
confident that it will activate and we'll be back up to full capacity in the
carbon dioxide removal operations," said Mike Suffredini, NASA's space station
program manager, in an afternoon briefing.
The space
station relies on American and Russian air scrubbers to continually refresh the
its internal atmosphere. Both are required to support the station's full-six
man crew. If the repairs to NASA's air scrubber are unsuccessful, the station
has a stockpile of lithium hydroxide canisters that can also be used to purify
the station's cabin.
That
stockpile could support the station's six-person crew for up to two months if required,
Suffredini said. NASA's space shuttle Discovery, meanwhile, is already expected
to deliver a new American air-scrubbing device to the station in late August as
part of a preplanned supply mission.
That
mission is slated to launch on Aug. 25.
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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