During various discussions with my students about the Columbia disaster, I was asked, "How many astronauts have died?" My response - "Twenty-one. The seven people on the Columbia, the seven people on the Challenger, the three people in the Apollo 1 fire, and four Soviet cosmonauts."

The inevitable followup question: "Was Apollo 1 featured at the beginning of Apollo 13?"

Yes, yes it was.

If you'd like to take a few minutes to commemorate the lives of these brave men and women, I've added a Fallen Astronauts section to my website. I've also included some NASA links to information about Columbia.