CAPE CANAVERAL, Fla. - Six astronauts aboard NASA's space shuttle Atlantis are
spending what is expected to be their last day in orbit, though poor landing
weather could keep them spaceborne for one more day, mission managers said Tuesday.
NASA entry
flight director Steven Stitch said high winds at Atlantis' Shuttle Landing
Facility runway here at the Kennedy Space Center (KSC) may prevent the
orbiter's planned Wednesday landing. Weather forecasts improve significantly
for a Thursday or Friday landing, he added.
"The
weather outlook for tomorrow is not as promising as I would like," Stitch said
during a status briefing for Atlantis'
STS-115 mission. "You'd like to come in with a nice, perfect forecast with
clear skies and no wind."
But that's
not the case for the end of what has been a widely
successful STS-115 mission to resume construction of the International Space
Station (ISS).
Cross winds
are expected to be higher than allowable for Atlantis' first landing
opportunity at 5:58 a.m. EDT (0958 GMT), with possible showers within a 30-mile
(48-kilometer) perimeter and a potential cloud ceiling of about 5,000 feet (1,524
meters).
NASA flight
rules for that landing attempt - which would occur in the predawn darkness - call
for cross winds of less than 12 knots (13 miles per hour), no rain within 30
miles (48 kilometers) and a thick cloud ceiling of no less than 8,000
feet (2,438 meters).
Atlantis'
STS-115 mission delivered a $372 million
pair of trusses and new solar arrays to the ISS, the station's first major
addition since late
2002. The planned 11-day mission featured three spacewalks to install the
17.5-ton Port 3/Port 4 truss segments and unfurl
the station's new solar wings.
Watching
weather
Stitch said
that, if the weather goes NASA's way, it could pass through Atlantis' return
runway in time for a second landing attempt in daylight at 7:33 a.m. EDT (1133
GMT).
"We're
going to try to be smart with the timeline," NASA astronaut Tony Antonelli,
serving as spacecraft communicator, told Atlantis' STS-115
commander Brent Jett this morning. "If it looks early like we don't have a
chance, we'll try to knock it off early so we don't waste your efforts."
"Obviously
we're ready to do whatever you guys need," Jett said. "And we'll be ready to go
tomorrow if the weather's good."
Only
Atlantis' KSC landing strip will be available Wednesday, though Stitch said he
could activate a backup site at California's Edwards Air Force Base in the Mojave Desert on Thursday depending on weather forecasts. A third landing site - Northrup
Strip at New Mexico's White Sands Space Harbor - is currently unavailable due
to standing water on its runways.
NASA would
prefer Atlantis return directly to KSC rather than touch down at Edwards and be
ferried by its carrier plane across the country, which typically costs about
one week in turnaround time and $1 million.
Stitch said
that Jett, like most shuttle commanders, has more time rehearsing landings at
KSC than at Edwards.
"And, of
course, it saves on the turnaround time," Stitch added.
NASA must
ready Atlantis to serve as a rescue craft to support the planned Dec. 14 launch
of its sister ship Discovery in case that orbiter suffers serious damage in
flight and its crew is forced to take refuge aboard the ISS.
"We'll
watch the weather carefully and if it's a good day to land, we'll do so,"
Stitch said, adding that the shuttle has enough supplies to last through
Saturday if needed.
Homeward
bound
While
mission controllers eye Atlantis' landing weather, the shuttle's astronaut crew
is preparing to say goodbye to space.
"This
flight has been everything that I could have imagined and more," STS-115
mission specialist Heidemarie Stefanyshyn-Piper, who is making her first
spaceflight and participated in two of the mission's three spacewalks, told
television reporters this morning.
Jett and
his fellow STS-115 crewmates spent much of today checking out their
spacecraft's systems to ensure all worked as it should. Astronauts fired the
orbiter's thrusters, activated its hydraulics and control surfaces - used in
the Earth's atmosphere - and set up the seats they will take during reentry.
The
astronauts also participated in a rare
orbital conference call with two other spacecraft crews - aboard the ISS
and its new crew approaching in a Soyuz
TMA-9 spacecraft - earlier today.
"We're
going to start converting the shuttle into its reentry mode, sort of like an
airplane," STS-115 mission specialist Daniel
Burbank told television reporters today. "We're just hoping the weather
will cooperate and we'll be able to get in on our first try tomorrow."
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