Spaceflight Now STS-107

Foam impact analysis expected no major damage
Posted: February 3, 2003

A NASA analysis of potential tile damage resulting from the impact of external tank foam insulation during the shuttle Columbia's launch concluded no significant damage would have resulted during re-entry even if multiple tiles were missing.

A tracking camera captures these views of foam insulation breaking free from the external fuel tank and striking the shuttle's left wing during launch. Photo: NASA
During Columbia's launching Jan. 16, long-range tracking cameras showed a relatively large piece of foam debris falling away from the shuttle's external tank and striking the underside of the orbiter's left wing. The debris is believed to have measured about 20 inches in its longest dimension.

The actual impact occurs out of view under the wing, but a cloud, or spray, of fine white material erupts from the area and quickly streams away in the shuttle's exhaust plume. The video, obtained earlier by CBS News and other organizations, was released by NASA today.

Columbia was destroyed during re-entry Saturday, breaking apart 200,000 feet above Texas while streaking toward the Kennedy Space Center at more than 18 times the speed of sound.

Telemetry from the shuttle indicates a sudden temperature rise in the left landing gear wheel well and above the wing along the left side fuselage. It is not known what caused the thermal distress, but it actually began seven minutes or so before the shuttle broke up.

The impact of the foam debris on the underside of the wing near in the general area of the left main landing gear door has prompted speculation about possible tile damage that could have worsened during entry.

An analysis by NASA engineers while Columbia was still in orbit, however, concludes that while the impact and resulting heat stress could have caused structural damage in the immediate area, it would not have led to a loss of the vehicle. The analysis, or at least this summarization of it, was dated Jan. 28 - the 17th anniversary of the 1986 Challenger disaster.

The engineers assumed the debris was foam insulation and studied possible damage scenarios based on the visible trajectory of the foam.

Damage to the reinforced carbon-carbon composite insulation on the leading edge of the wing would have been limited to "coating only and have no mission impact," the update said.

But impact on the black thermal protection tiles on the belly of the orbiter had the potential "for a large damage area to the tile."

A thermal analysis was performed to determine the implications of such damage assuming various levels of damage, including multiple tiles missing over an area measuring roughly 7 by 30 inches.

"These thermal analyses indicate possible localized structural damage but no burn-through and no safety of flight issue," the status report concluded.

Shuttle program manager Ronald Dittemore said much the same thing during a news briefing Sunday. While he did not provide test data, he said engineers still believed the impact was insignificant.

NASA plans two news briefings today, one from Washington at 11:30 a.m. EST and another from the Johnson Space Center at 4:30 p.m.

Multimedia clips
This long-range tracking camera footage shows foam insulation breaking free from the external fuel tank and striking the shuttle's left wing during launch.
  PLAY (16sec QuickTime file)

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