NASA
will start fixing a damaged Florida launch pad Friday in preparation for the
October launch of space shuttle Atlantis in a mission to repair the Hubble
Space Telescope.
The
intense pressure from space shuttle Discovery's May
31 launch tore bricks from the wall of Launch Pad 39A's flame trench and
sent some pieces flying at supersonic speeds, but NASA officials said that the
incident did not pose a threat to the space shuttle or its launch schedule.
"It's
not a flight [safety] issue at all," said Rita Willcoxon, space shuttle
processing manager, during a Thursday teleconference where she and other
officials laid out the results of NASA's investigation and repair plans.
NASA
engineers found that time and environmental effects had eroded the adhesive
materials holding a layer of heat-resistant bricks against the east wall of the
flame trench. Vibrations during Discovery's launch caused that layer to bend
outwards slightly, and allowed a hot gas plume to enter behind the bricks.
"Due
to interlocking nature of the bricks, that led to cascading failure," said
Perry Becker, head of the Engineering Investigation Team.
The
thrust from Discovery's engines blasted 3,500 bricks (newly revised estimate)
from the wall and left them strewn across 1,500 feet (457 meters) between the
flame trench and the pad's perimeter fence. However, simulations run by the
engineers showed that none of the bricks flew up near the pad surface, and
therefore posed no possible risk to the space shuttle.
Erosion
has similarly taken its toll on the intact west wall of the flame trench. NASA
crews plans to work with an outside contractor to repair the damaged east wall,
but will also replace a 25-foot high by 80-foot wide section of the west wall's
bricks using a spray-on, heat resistant material.
NASA
has two launch pads for Atlantis and the remaining shuttle missions, but will
need both ready for the Hubble
repair mission in case a second shuttle must fly on a rescue mission.
That's because the Hubble Space Telescope sits in a different orbit than the
International Space Station, and so Atlantis would be unable to reach the safe
haven of the orbital outpost during an emergency.
The
repair effort would allow plenty
of time for the Atlantis launch to proceed as planned, NASA officials
confirmed. Brick removal starts Friday and ends on July 19, and the wall repair
is slated to go from the third week of July until the third week of August.
"That
repair will remain intact until the end of the shuttle program," Willcoxon
said. She added that the total cost for the flame trench facelift was expected
to fall under $2.7 million.
NASA
already has plans to redo the launch pads after the shuttle's retirement, and
prepare them for the Ares I rockets that will carry the Orion
capsule replacing the shuttle.
This
story was updated on June 27, 2008 at 10:50 a.m. EST.
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