NASA orders more shuttle fuel tank fixes

By Irene Klotz

CAPE CANAVERAL, Florida (Reuters) – NASA space shuttle
managers ordered additional redesigns on Thursday to the ships’
fuel tanks but still believe shuttle flights can resume as
early as May, a top U.S. space agency official said.

Over the next several weeks, engineers planned to test and
analyze several options for using the tanks without protective
foam ramps that shield underlying cables and pressurization
lines from the supersonic speeds of launch.

Part of a foam ramp, which protrudes 8-10 inches from the
surface of the tank, fell off during launch of NASA’s first,
and so far only, shuttle mission since the 2003 Columbia
disaster, which also was triggered by falling foam.

Analyzing another tank, engineers discovered cracks
throughout the foam ramp, setting off fresh concerns about how
to stop large chunks of foam insulation from breaking off the
tank during launch and possibly striking the orbiter.

The cracking is believed to be caused by the extreme cold
of the cryogenic propellants used for launch.

“We’ve decided not to fly with the (ramps), but we have to
put some kind of (protective covering) in that area,” NASA’s
spaceflight chief Bill Gerstenmaier said during a
teleconference with reporters.

“There are multiple solutions,” he added. “(Engineers) are
just trying to decide which one of those is the right one to do
that gives us the right safety margins.”

FINISH THE SPACE STATION

NASA needs to get its shuttle fleet flying again to finish
construction of the half-built International Space Station
before the ships are retired in 2010. For now, NASA is aiming
to fly 18 more shuttle missions to the space station and one
mission to service the Hubble Space Telescope.

The agency also wants to move ahead as quickly as possible
with developing a new spaceship to return astronauts to the
moon.

The decision to retire the shuttles and begin a new human
spaceflight initiative stems in part from the Columbia
accident, which exposed flawed safety assumptions held by NASA
for years.

The accident was caused by a piece of foam insulation that
fell off during launch and hit Columbia’s wing. As the shuttle
attempted to fly through the atmosphere 16 days later upon its
return, it was torn apart, killing all seven astronauts aboard.

NASA grounded the fleet for repairs and spent more than
$1.5 billion to fix the tank and other safety upgrades. The
work fell short and the fleet was grounded again after
Discovery’s flight in July.

“We want to get back flying as soon as we can, but we’re
not overly pressured. We’ll do that at the right time,”
Gerstenmaier said. “This is a small investment to get back a
tremendous capability and that is to complete the International
Space Station (and) prepare ourselves for exploration.”