Above: Space shuttle Columbia lifting off at the beginning of STS-107, its 28th and final mission. Courtesy of NASA.

To NASA, it's STS-107. To most of the rest of the world, it was the Space Shuttle Columbia disaster of 2003. A briefcase-sized chunk of foam weighing a little over a pound hit the orbiter's wing at 800 feet per second — that's about 550 miles per hour — damaging the thermal protection system (TPS). The compromised TPS was not adequate to the 3000° F reentry temperatures, and on its landing approach, the shuttle broke up into a handful of fireballs over Texas and Louisiana.

The shuttle disaster happened on my birthday. It's the worst birthday I have ever had.

This catastrophic event recalled to mind the Challenger disaster of 1986, seventeen years and four days earlier. I was in elementary school, and they wheeled a TV into our classroom so we could watch the shuttle explode over the Atlantic Ocean.

Stephanie Barr is a NASA engineer who writes the blog Rocket Scientist. She was part of the STS-107 team, and has a blog post remembering the Columbia tragedy. Go over and read it right now. I'll wait.

Then come back and tell me where you were when the Challenger and Columbia disasters happened.