NASA memo warned of 'potential for large damage'
HOUSTON, Texas (CNN) -- A few days before the Columbia shuttle disaster, NASA noted that debris that hit the left wing during takeoff created "the potential for a large damage area to the tile."
In an internal memo obtained by CNN, the space agency said the incident should have "no mission impact." But now, NASA says, "it may certainly be the leading candidate" in the search to explain the shuttle's breakup during re-entry Saturday.
The memo was written twelve days into Columbia's mission by the manager of the mission evaluation room (MER), where engineers monitor components of the orbiter during shuttle flights.
The memo said analyses indicate "possible localized structural damage but no burn-through, and no safety of flight issue" from the insulation that fell off an external fuel tank when Columbia blasted off.
The full memo reads:
The STS-107 mission is progressing nominally and all Orbiter subsystems are performing satisfactorily. No Orbiter issues have been reported in the previous 24 hours. The Orbiter consumables remaining are above the levels required for completion of the planned mission.
Regarding the debris hit on the left wing last discussed in the Fourth Daily Report; systems integration personnel performed a debris trajectory analysis to estimate the debris impact conditions and locations. This analysis was performed utilizing the reported observations from the ascent video and film. It was assumed that the debris was foam from the external tank.
Based on the results of the trajectory analysis, an impact analysis was performed to assess the potential damage to the tile and radial carbon carbon (RCC).
The impact analysis indicates the potential for a large damage area to the tile. Damage to the RCC should be limited to coating only and have no mission impact.
Additionally, thermal analyses were performed for different locations and damage conditions. The damage conditions included one tile missing down to the densified layer of the tile and multiple tiles missing over an area of about 7 in [inches] by 30 in.
These thermal analyses indicate possible localized structural damage but no burn-through, and no safety of flight issue.
Don L. McCormack Jr.
STS-107 Lead MER Manager