July 12, 2005

Shuttle returns to space after 2-1/2 year hiatus

By Michael Christie

CAPE CANAVERAL, Fla. (Reuters) - NASA returns to human
space flight on Wednesday with its first space shuttle mission
since Columbia disintegrated 2 1/2 years ago, killing seven
astronauts and spilling debris over Texas.

When Discovery blasts off from Cape Canaveral in Florida on
a plume of fire at 3:51 p.m. (1951 GMT), it will kick-start the
stalled construction of the International Space Station and
also mark, U.S. space officials say, the first step on the road
back to the Moon, and to Mars and beyond.

Many things can still go wrong.

Thunderstorms that are a part of Florida's humid summer may
force a delay; technical problems with one of the shuttle's 2.5
million parts are not ruled out; and $1 billion and countless
hours of manpower spent to avoid a repeat of the Columbia
disaster may not have been as successful as NASA hopes.

"It's a dangerous business. It will be for the foreseeable
future. We work every time to make it less dangerous than the
time before, every time to make it more reliable than the time
before," NASA administrator Michael Griffin said.

"But this is a matter to be regarded with the perspective
of generations, and not weeks, months. With 113 launches under
our belt, this is still an experimental test flight program,"
Griffin said at a final preflight briefing on Tuesday.

A last-minute mishap on Tuesday highlighted the dangers. A
falling window cover damaged two heat resistant tiles near
Discovery's tail as the hulking shuttle sat on the launchpad,
briefly casting doubt on the launch schedule.

Columbia fell apart on Feb. 1, 2003, because falling foam
from the external fuel tank had knocked a hole in its wing
during liftoff 16 days before. When the shuttle returned to the
Earth's atmosphere, superheated gases ate into the breach.

Much of NASA's efforts since have been directed at
minimizing the possibility of falling debris at liftoff and one
of Discovery's main missions will be to see whether those
efforts have paid off, and to try out experimental repair
techniques if they have not.


The conditions Discovery and her crew, commanded by veteran
astronaut Eileen Collins, will face are daunting. Its two solid
rocket boosters will pour out 6.5 million pounds (3 million kg)
of thrust and enough energy to light 87,000 homes for a day.

Weather conditions will have to be perfect, not just in the
flight path but at emergency landing zones at Cape Canaveral,
elsewhere in the United States and in Europe.

Discovery's other mission is to deliver needed supplies to
the International Space Station, a 16-nation project.

Construction of the station has been on hold since the
three remaining space shuttles were grounded after the Columbia
accident, and it has been run by a two-man skeleton crew.

The International Space Station will serve as a safe haven
for shuttle astronauts if Discovery is damaged and has enough
oxygen, water and supplies to accommodate the seven-person crew
for about eight weeks. It will provide the same function to the
next scheduled shuttle mission in September.

After that, Griffin said on Tuesday, shuttle missions will
be on their own because NASA will not be able to reserve a
second shuttle to act as a rescue craft and still keep to the
schedule of delivering parts to the station to allow its
construction to be completed by 2010.

Under a new vision for space exploration announced by
President Bush, the shuttle's return to flight, and the
completion of the space station, are essential steps toward the
shuttle fleet's retirement.

Once mothballed in 2010, the aging shuttles will in theory
be replaced by a new generation of spacecraft that will allow
humankind to return to the Moon, and eventually to Mars.