More Cracks in Discovery's External Tank Found

Space shuttle Discovery’s final launch was postponed on November 5 because of a gas leak, but since then engineers have found four cracks in the External Tank’s foam. The fourth was discovered this weekend.

Spaceflightnow.com reports that engineers have replaced a misaligned fitting that caused the gas leak, but are still assessing the cracks:

“Engineers first spotted a large crack in the foam insulation near the top of the intertank section. When the foam in the area was cut away for repairs, engineers found two 9-inch cracks in the flat attachment plates on either side of an underlying stringer known as S-7-2. NASA managers then decided to cut away additional foam and a third crack was found Friday on the stringer to the immediate left of the one that was initially discovered.

“Over the weekend, a fourth crack was found in the left-side stringer, known as S-6-2, sources said. No cracks were found in stringers on the right side.”

The website adds that cracks are not unusual, but these are the “first to be found at the launch pad, where access is more difficult.”

NASA says that senior managers will meet on November 22 to review launch preparations. The earliest the shuttle can launch is November 30 because of sun angles at the International Space Station, with which it will dock. A launch date has not officially been set.