Endeavour Incident Moves Up On-Orbit Demonstration
A planned test of on-orbit repair procedures for cracks and
other breakages in the thermal tile heat shield onboard the space
shuttle has been moved up over a year, after last month's flight of
the shuttle Endeavour almost had to put those theories to the test
NASA plans to test a tile patch repair on next month's flight of
the shuttle Discovery, according to The Associated Press.
A fifth spacewalk will be added to Discovery's two-week flight
to conduct the test, in which two astronauts will squirt a
salmon-colored thick liquid -- similar in consistency to peanut
butter -- onto a deliberately damaged shuttle tile. Astronauts will
then use small foam brushes to smooth the material.
Shuttle program manager Wayne Hale called the demonstration "a
confidence builder," adding the test has been conducted several
times on the ground, but never in space.
The liquid tends to bubble on Earth, according to NASA, and the
agency wants to know whether the same problem will occur in space.
The repaired tile will be returned to Earth for analysis.
The repair procedure was one of three NASA considered last
month, to repair a gouge in heat resistant tiles on the belly of
the shuttle Endeavour (below). As ANN reported, the damage
was caused by foam insulation striking the orbiter during its
August 8 launch.
NASA ultimately decided no repair was necessary, and Endeavour
returned to Earth safely. Fears the damage would lead to secondary,
non-catastrophic heat damage to the orbiter's aluminum skin also
proved to be unfounded.
Dr, Scott Parazynski, the astronaut who will conduct the
simulated repair, compared the work to delicate surgery.
"This is a very exciting time for us to finally get the ground
truth if you will -- or the space truth -- on how this material
behaves," he said, adding he was confident the repair could have
worked on Endeavour's damage.
NASA hasn't tested the procedure before, over concerns of
toxicity and the unwieldly tools required to conduct the repair.
Some progress has been made in both areas since the procedure was
first developed after the 2003 loss of Columbia.
A caulk-line gun replaced a much-bulkier applicator, and NASA
determined a smaller amount of the toxic substance than first
thought is necessary for most repairs.