This story was updated at 9:54 a.m. EDT.
CAPE
CANAVERAL, Fla. -- NASA is hoping for a break in the weather in order to bring
the space shuttle Atlantis and its seven-astronaut crew back to Earth later
today.
Rain
showers and low clouds near NASA's Shuttle Landing Facility here at the Kennedy
Space Center (KSC) prevented
a Thursday return for the shuttle and its STS-117 astronaut crew.
The orbiter is now slated to land at 2:18 p.m. EDT (1818 GMT) at KSC.
"We're
going to be facing the same challenges at KSC," NASA astronaut Tony Antonelli,
serving as spacecraft communicator, told the Atlantis crew of today's expected weather
conditions.
Mission
managers are also calling up NASA's backup shuttle landing site at Edwards Air
Force Base in California in case the weather proves untenable in Florida, he
added.
Commanded
by veteran shuttle flyer Rick Sturckow, Atlantis' STS-117 crew is returning
home after a now 14-day mission to boost the power grid aboard the International
Space Station (ISS).
The shuttle
astronauts installed new starboard
trusses and solar arrays, furled an older solar wing and swapped out one of
the station's three-person Expedition 15 crew. The crew also repaired
a torn thermal blanket on Atlantis' aft Orbital Maneuvering System (OMS)
pod using surgical staples and medical staplers scavenged from shuttle and ISS
medical kits.
Returning
to Earth with Sturckow are shuttle pilot Lee Archambault and mission
specialists Patrick Forrester, Steven Swanson, James Reilly II, Danny Olivas
and Sunita Williams.
Williams is
returning to Earth after 194 days in space as part of the station's Expedition
14 and 15 crews. She has set
a new world record for the longest duration spaceflight by a female
astronaut and was replaced by fellow U.S. spaceflyer Clayton Anderson during
the STS-117 mission.
Deorbit
decision
Atlantis
carries enough supplies to stay in orbit until Sunday, though mission managers
have set a Saturday deadline for any weather-related delays in order to keep a
one-day margin in reserve in case of a technical glitch.
In all,
there are two landing opportunities at KSC and three at Edwards, though some
windows overlap.
If rain and
low clouds again prevent Atlantis from landing at KSC on the first attempt, the
shuttle could try to wait out the weather for an extra orbit and touch down in
Florida at about 3:55 p.m. EDT (1955 GMT).
"It will be
a real-time call," NASA spokesperson Allard Beutel said Thursday.
But if, in
that one orbit, the weather does not improve, the shuttle could instead press on
towards Edwards for a 3:49 p.m. EDT (1949 GMT) landing thanks to a brief engine
burn late Thursday by the Atlantis crew. That maneuver, mission managers hope,
could allow Atlantis to reach Edwards before the arrival of high winds during
two later California landing opportunities, which arise at 5:23 p.m. EDT (2323
GMT) and 6:59 p.m. EDT (2259 GMT).
"Sounds
like a nice game plan," Sturckow told Mission Control Thursday after hearing
today's landing options.
NASA
prefers to land shuttles at KSC, home to the orbiters' hangars and launch pads,
because of the time and cost saved to once more prime them for flight.
Atlantis is
slated for a second launch this year in December, when the shuttle is expected to
haul the European Space Agency's Columbus laboratory to the ISS.
A landing
at the Edwards site would cost an additional $1.7 million and add between seven
to 10 days to ferry Atlantis back to KSC for refurbishment for its next
mission, NASA officials said Thursday.
"Obviously,
we'd prefer to stay at the Cape if we can," John Shannon, NASA's deputy shuttle
program manager, before Atlantis' first landing attempt.
During
their mission, Atlantis astronauts also helped Expedition 15 crew resolve a
major Russian
computer system shutdown last week that ultimately required an improvised
set of shunts, or jumper cables, to bypass surge-protector like circuits in six
vital control and navigation computers.
Expedition
15 astronauts removed the jumper cables from some of the computers Thursday in additional troubleshooting
efforts to see if they would still function properly, but they would not, NASA officials said.
NASA is
broadcasting the space shuttle Atlantis' STS-117 mission live on NASA TV. Click here for mission updates and
SPACE.com's video feed.
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