CAPE
CANAVERAL, Fla. - After a few false starts, NASA's shuttle Atlantis stands poised
to launch six
astronauts and a hefty addition towards the International Space
Station (ISS) today to jump
start construction of the orbital laboratory.
With
veteran shuttle flyer Brent
Jett in command, Atlantis' STS-115 astronaut crew is set to rocket toward
the ISS at 12:28:46 p.m. EDT (1628:46 GMT) from NASA's Pad 39B launch site here
at the Kennedy Space Center (KSC). The shuttle crew and flight controllers have
spent more than four years preparing to deliver a $371.8-million set of new trusses
and solar arrays to the ISS, only to be frustrated by additional weather
delays last week.
"These guys
deserve a break with the weather," Jett said Saturday of the shuttle workers
and flight controllers. "We hope they see Atlantis leave the pad on Wednesday."
Current
forecasts predict a 70 percent chance of favorable weather conditions for
today's planned space shot, with only clouds and isolated showers presenting a
threat at launch time. NASA has two
more opportunities to launch Atlantis this week - Thursday and Friday -
before standing down to avoid
conflicts with an upcoming Russian Soyuz launch carrying a new crew to the
ISS on Sept. 18.
Joining Jett
on the STS-115 spaceflight are shuttle pilot Chris
Ferguson and mission specialists Joseph
Tanner, Daniel
Burbank, Heidemarie
Stefanyshyn-Piper and Steven
MacLean of the Canadian Space Agency. Their mission is NASA's third since
the 2003 Columbia accident
and the first dedicated to ISS construction since late
2002.
"I think we're
all excited, of course," NASA launch integration manager LeRoy Cain said
Tuesday. "We've worked so hard to get to this point."
Originally
set to launch on Aug. 27, Atlantis' STS-115 mission was delayed first due to a launch
pad lightning strike, which prompted subsequent
systems checks to ensure the shuttle and its boosters were unscathed
from the 100,000-amp bolt. Flight controllers then hauled Atlantis off its
launch pad to shield it from what was then Tropical
Storm Ernesto.
But they stopped
in mid-journey to NASA's massive Vehicle Assembly Building as Ernesto weakened,
and returned to Pad 39B in an unprecedented
move to preserve this week's launch attempt.
"As it's
been said, the first few inches are the hardest part of the whole flight," Cain
said. "And that's really true to a large extent. I'm excited, I think the whole
team is excited."
Milestone
mission
Atlantis'
STS-115 crew is hauling the 17.5-ton Port 3/Port 4 (P3/P4) truss segments to
the ISS along with a pair of expansive solar arrays to build up the outpost's
power grid.
The mission
is first of at least 15 planned shuttle flights by NASA and its international
partners to complete the ISS by September 2010, when the space agency plans to
retire its remaining three orbiters.
The mission
also marks a return to the $100 billion station's construction after the two test missions
that followed the loss of Columbia and its seven-astronaut crew. A chunk of
foam insulation from Columbia's external tank tore free during launch and
critically damaged the shuttle's heat shield, leading to its destruction upon
reentry.
Since then,
NASA has made incremental
improvements to shuttle fuel tanks to reduce the amount of foam shedding at
liftoff, and continues to seek additional avenues - such as changes to 16
foam-covered brackets known as ice
frost ramps - for modification.
"I'm
excited that after a substantial period of time of redesign and rethinking and
retooling and preparation, we are into the heart of the [ISS] assembly," NASA
space shuttle program manager Wayne Hale said this week. "We have certainly got
our fingers crossed that it's going to go very well and we've made plans that
cover every possible contingency that we can think of."
Three
spacewalks are planned during Atlantis' 11-day STS-115 mission to install
the new portside trusses and deploy the solar panels, which will have a
wingspan of about 240 feet once unfurled.
For Maclean
- one of four STS-115 spacewalkers who plans on being the first Canadian to
actually wield the space station's Canadian-built robotic arm - that mission
begins at 8:38 a.m. EDT (1238 GMT) today, when he and his crewmates walk out of
their quarters and head to the launch pad.
"For me,
walking out to the pad...will be much like walking into an Olympic stadium for
your athletic events," the Canadian astronaut said. "Many countries will be
participating in the spirit of international cooperation, and our family and
our friends, who believe in what we do, will be in the front seats."
MacLean has
repeatedly said that the busy STS-115 mission will not only be busy, but
eye-catching when he and his crewmates deploy the new ISS solar arrays.
"It's complex
what we do, it's not easy," Maclean said. "I promise you we'll bring home a
gold medal."
NASA will broadcast Atlantis' launch countdown and planned liftoff on NASA TV beginning at about 6:30 a.m. EDT (1030 GMT). You are invited to follow the countdown's progress using SPACE.com's feed, which is available by clicking here.
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