* Shuttle to leave station at 11:55 p.m. EDT Sunday
* Landing scheduled for 2:35 a.m. EDT Wednesday
* NASA's final shuttle mission to fly in July
By Irene Klotz
CAPE CANAVERAL, Fla. (Reuters) - The shuttle
Endeavour astronauts packed gear and prepared to leave the
International Space Station on Sunday, wrapping up a 12-day
visit to complete construction of the U.S. side of the orbital
The crew cleaned up from their four spacewalks and
reinstalled the station's upgraded air purification system, the
last maintenance task on a long to-do list that included
servicing the station's cooling and power systems and extending
the reach of its robotic crane.
Hatches between the shuttle and station were to be closed
at 6:56 a.m. EDT, with Endeavour's departure slated for 11:55
Landing is scheduled for early Wednesday at the Kennedy
Space Center in Florida, where workers were preparing NASA's
last space shuttle to be rolled out to the launch pad. Atlantis
and a crew of four are scheduled to close out the 30-year-old
shuttle program with a final cargo run to the station in July.
"We're really pleased to be able to help round out the
program with the successful work that we've had up here,"
Endeavour lead spacewalker Drew Feustel said during an inflight
"There's one more flight after us and they'll finish out
the space shuttle program. We really believe that we're ending
on a very strong and positive note and looking forward to
future opportunities," he said.
The United States is retiring its three space shuttles due
to high operating costs and to free up funds to develop new
spaceships that can carry astronauts beyond the station's
220-mile high orbit where the shuttles cannot go.
"Once the space shuttle retires we're going to lose a lot
of capability of moving large payloads out in space, but then
that opens the doors for new things that are going to come
across the horizon," said Endeavour's pilot, Greg Johnson.
The primary goal of Endeavour's flight, the 134th for
NASA's space shuttle program, was to deliver and install the $2
billion Alpha Magnetic Spectrometer particle detector, designed
to study dark matter, antimatter and other high-energy
phenomena that cannot be detected by telescopes.
That job was accomplished shortly after Endeavour's May 18
arrival at the $100 billion space station, a project of 16
nations that has been under construction since 1998.
Atlantis will be delivering a year's worth of supplies to
the station. NASA is turning over U.S. cargo runs to two
companies, Space Exploration Technologies and Orbital Sciences
Corp., and hopes commercial flights will be available to ferry
station crew members as well within four or five years.
In the interim, Russia will provide space taxi services, at
a cost of more than $50 million a seat. Russia, Europe and
Japan also fly cargo ships.
© 2014 Thomson/Reuters. All rights reserved.