Tomorrow is the 25th anniversary of the Challenger disaster, a news event that remains so vivid -- especially to Houstonians -- that most everyone can remember where they were when they learned of it or when they first saw a replay of that launch, embedded above.

That day and its aftermath triggered a wide range of emotions, from shock to anger to inspiration. There were five moments, though, that were chilling.

5. "Obviously a major malfunction." For long seconds after the fireball erupted, and cameras simply showed the smoky trails, it was perhaps possible for people who paid no attention to the space program to think they'd seen the kind of booster separation that happens on launches. But stunned spokesman Steve Nesbitt, uttering the obvious because there was little else to say, cut off any such hope.

4. What? Cold Affects an O-Ring? Richard Feynman was the thinking man's Carl Sagan, someone who could break down scientific concepts into easily digested information. He did it most memorably in the hearings investigating the disaster, when he showed that cold conditions can affect the o-rings that should never, ever be affected in that manner.

After he did, it was hard not to think, "Isn't that something NASA should have considered?"

3. Did they live for long on the way down? Seeing the explosion (which wasn't technically an explosion, of course) offered only one, extremely slight, positive thought: At least they never knew what hit them.

Wrong, as it turns out. Evidence began to seep out eventually that the crew cabin had been thrown away from the flames, and that some safety procedures had been started. That brought out the ghouls -- a famous hoax transcript was believed to be true by some ("God -- the water! We're dead -- (screams in background)") -- but the actual evidence was just as eerie. Some emergency oxygen kits had been started and used. And safety switches had been toggled even though they had guards that meant a human -- and not the force of the explosion -- had moved them.

Most experts believe the astronauts survived, but almost immediately lost consciousness due to a lack of cabin pressure. A few disagree.

2. The plumes are seen After the event, investigators studied every inch of video of the takeoff, examining it frame by frame for evidence of what happened. Soon enough they saw something: A plume of flame opening up on the rocket, where no plume should be. Knowing what happened, the plume was like the first sign of impending catastrophe.

1. "Slipped the surly bonds of earth..." We've never been the biggest fans of speechwriter Peggy Noonan's brand of treacle, but she -- and Ronald Reagan -- shone brilliantly on the day of the disaster. Reagan spoke from the Oval Office, paying tribute and assuring the space program would go on. He tended by memorably summoning up memories of the final few happy moments before the explosion when he quoted aviation poet John Magee: