As is done after every launch, within two hours of the lift-off the Intercenter Photo Working Group examined video from tracking cameras. An initial review did not reveal any unusual events. The next day, when the Intercenter Photo Working Group personnel received much higher resolution film that had been processed overnight, they noticed a debris strike at 81.9 seconds after launch.

A large object from the left bipod area of the External Tank struck the Orbiter, apparently impacting the underside of the left wing near RCC panels 5 through 9. The objects large size and the apparent momentum transfer concerned Inter-center Photo Working Group personnel, who were worried that Columbia had sustained damage not detectable in the limited number of views their tracking cameras captured. This concern led the Intercenter Photo Working Group Chair to request, in anticipation of analysts needs, that a high-resolution image of the Orbiter on-orbit be obtained by the Department of Defense. By the Boards count, this would be the first of three distinct requests to image Columbiaon-orbit. The exact chain of events and circumstances sur-rounding the movement of each of these requests through Shuttle Program Management, as well as the ultimate denial of these requests, is a topic of Chapter *6.

After discovering the strike, the Intercenter Photo Working Group prepared a report with a video clip of the impact and sent it to the Mission Management Team, the Mission Evalu-ation Room, and engineers at United Space Alliance and Boeing. In accordance with NASA guidelines, these contrac-tor and NASA engineers began an assessment of potential impact damage to Columbias left wing, and soon formed a Debris Assessment Team to conduct a formal review.

The first formal Debris Assessment Team meeting was held on January 21, five days into the mission. It ended with the highest-ranking NASA engineer on the team agreeing to bring the teams request for imaging of the wing on-orbit, which would provide better information on which to base their analysis, to the Johnson Space Center Engineering Management Directorate, with the expectation the request would go forward to Space Shuttle Program managers. De-bris Assessment Team members subsequently learned that these managers declined to image Columbia.

Without on-orbit pictures of Columbia, the Debris Assess-ment Team was restricted to using a mathematical modeling tool called Crater to assess damage, although it had not been designed with this type of impact in mind. Team members concluded over the next six days that some localized heating damage would most likely occur during re-entry, but they could not definitively state that structural damage would result. On January 24, the Debris Assessment Team made a presentation of these results to the Mission Evaluation Room, whose manager gave a verbal summary (with no data) of that presentation to the Mission Management Team the same day. The Mission Management Team declared the debris strike a "turnaround" issue and did not pursue a request for imagery.

Even after the Debris Assessment Teams conclusion had been reported to the Mission Management Team, engineers throughout NASA and Mission Control continued to ex-change e-mails and discuss possible damage. These messag-es and discussions were generally sent only to people within the senders area of expertise and level of seniority.