NASA is observing the anniversaries of its human losses in spaceflight: Apollo 1 (forty four years ago yesterday), Challenger (twenty five years ago today), and Columbia (eight years ago next Tuesday, February 1).
Today's twenty fifth anniversary of the loss of the Challenger crew brought back particular memories of that day when I was working in California in support of operations of the primary payload mission. We'd gotten to meet some of the crew during preparations for that mission.
Clark Lindsey has some Challenger anniversary links. Below are videos of the launch as covered by CNN and of President Reagan's moving address from the Oval Office that day.