CAPE
CANAVERAL, Fla. - The successful predawn
landing of NASA's space
shuttle Atlantis today marked just the start of what will be an
ever-increasing challenge of completing the International Space Station (ISS),
the agency's top official said Thursday.
"We are
rebuilding the kind of momentum that we've had in the past and that we need if
we're going to finish the space station," NASA chief Michael Griffin said after
Atlantis' flawless landing here at the Kennedy Space Center. "We have an
awesome task ahead of us. The space station is half-built
and we have half to go."
Atlantis' six-astronaut
crew completed a 12-day
mission to the ISS at 6:21 a.m. EDT (1021 GMT) when the orbiter's
wheels met the tarmac of Runway 33 here. The STS-115 astronauts - commanded by veteran
shuttle flyer Brent Jett - delivered a massive 17.5-ton
pair of trusses and new
solar arrays to the ISS during a busy mission to kick off an orbital
construction effort that stalled as NASA recovered from the 2003 Columbia accident.
"It was a
pretty tough few days for us," Jett said from the Shuttle Landing Facility
runway. "But we got a lot more missions coming up and they're going to be just
as difficult."
NASA plans
at least 14 more shuttle flights - beginning with STS-116 aboard the Discovery
orbiter in December - to complete the ISS by September 2010, when the agency
plans to retire its orbiter fleet to make way for its new Orion
capsules. Atlantis is slated to launch NASA's STS-117 mission to the ISS in
early 2007.
Michael
Leinbach, NASA's launch director, said Atlantis' multiple launch postponements
- and then its one-day landing delay - have cut a planned 110-day turnaround
for the orbiter by more than 10 days.
"It will be
the most aggressive turnaround that we've had since return to flight, but the
team is up for that," Leinbach said.
Upcoming
ISS construction missions include a complete rewiring of the station's
electrical grid and cooling systems, the delivery of two more solar arrays and
the launch of critical connecting nodes and orbital laboratories.
"It's maybe
a little simpler than trying to build an aircraft while you fly it, but not by
much," Griffin said of ISS assembly.
On top of
STS-115's already challenging goal of resuming ISS construction, space station
officials wrangled
an orbital traffic jam to ensure that Atlantis' astronauts completed their
mission and undocked
before a Russian-built Soyuz spacecraft arrived
this week with a new crew
and a space
tourist.
"I was
wondering at one point if we needed to install a traffic light on one or our
EVAs," Lynn Cline, NASA's deputy associate administrator of space operations,
said of the STS-115 flight's three spacewalks. "We did have a lot of vehicles
and basically we took it one step at a time."
The
challenge, Cline said, required not only that Atlantis leave the ISS before the
Soyuz arrived, but also that the space station's three Expedition
13 astronauts were rested and ready to help jettison
a Russian Progress cargo ship to clear a berth for the incoming spacecraft.
"This is a
lesson we need to learn, how to handle multiple vehicles and multiple
constraints," Cline added.
For the
crew of Atlantis, today's successful landing marked the end of what had been a
smooth flight aboard the 100-ton space plane.
"Atlantis
was a terrific ship," Jett told KSC workers after leaving the orbiter. "She
gave us absolutely no problems at all during the mission."
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