Shuttle's long-ignored pinholes eyed as factor

Houston Chronicle 03/13/03

WASHINGTON -- Experts have told NASA for years that covering the wings of a space shuttle
while it sits on the launch pad could prevent a problem that investigators now think may have
contributed to the destruction of Columbia.

But NASA ignored the recommendation, one expert said Wednesday, even though the idea
had been endorsed by top materials researchers inside and outside the space agency.

Their suggestion was simple: drape the equivalent of a painter's drop cloth over the shuttle's
wings to protect them from corrosive sea air, preventing tiny pinholes from forming on the
edges of the wings.

Those pinholes -- about as wide as three human hairs -- began to appear on the leading
edges of shuttle wings in 1992, first in Columbia, then other shuttles. Pinholes develop after
about 10 flights. The oldest shuttle, Columbia, broke apart at the end of its 28th flight, and it
had far more pinholes than any other shuttle, according to NASA technical reports.

The Columbia Accident Investigation Board is looking at the pinholes as a possible
contributing cause of the Feb. 1 tragedy, board member Maj. Gen. John Barry said Tuesday.
Investigators are trying to find the cause of a breach in Columbia's left wing that allowed hot
gas into the shuttle as it re-entered Earth's atmosphere, starting the fatal break-up.