The main one turned out to be a section of the huge external fuel tank.

The stringer issue with the external tank is example enough of why.

All these cases did not involve debris from the external tank.

Three other external tanks were in preparation, when the manufacturing stopped.

Its job done, the external fuel tank separated and fell away.

The plant's sole purpose is to produce the $43 million external tanks.

Very similar to the Norwegian version but with external fuel tanks.

But the shedding of foam from the external tank has always been different.

They noticed on the day after launch there was some debris coming off the external tank.

With Columbia, there was a history of foam coming off the external tank during launch.