The space shuttle Atlantis almost blew up in 1988 due to an identical problem -- damaged heat shield tiles -- that ultimately brought down the shuttle Columbia 15 years later.

The exhaustive attention NASA now devotes to making sure shuttle heat shields are damage-free and safe for re-entry is a direct result of the 2003 Columbia disaster. But a blacked-out military flight 21 years ago still stands out as a warning to astronauts, engineers and managers, a frightening "close call" that had the potential to bring the shuttle program to an early end.

It was that close.

"I will never forget, we hung the (robot) arm over the right wing, we panned it to the (damage) location and took a look and I said to myself, 'we are going to die,'" recalled legendary shuttle commander Robert "Hoot" Gibson. "There was so much damage. I looked at that stuff and I said, 'oh, holy smokes, this looks horrible, this looks awful.'"

He was seeing the worst tile damage any shuttle had ever experienced.

But a perfect storm of poor communications, caused in part by military restrictions that prevented the crew from downlinking clear images showing scores of chipped and broken tiles, ultimately resulted in a flawed analysis on the ground that indicated the crew had nothing to worry about. Flight controllers were not convinced the shuttle was seriously damaged at all. Some engineers apparently believed the astronauts had been misled by poor lighting conditions and grainy TV images.

Read the whole thing, because it turns out that the guys on the ground got it wrong because they required video footage of the damage to be encrypted before it was transmitted. Think about what encryption in 1988 would've looked like (bad) and the engineers on the ground thought they were seeing shadows and not damaged tiles.

The main reason I link to this story is because Gibson is a Cal Poly grad and was the speaker at my graduation ceremony in the spring of 1994.

Turns out that he was very lucky to be there.