I saw it first-hand. I was about six yrs/old, visiting my cousins down in FL. I think we were in Orlando, but I can't be sure about that, though I can say that we were close enough to the launch to see it first-hand right after it took off and went into the sky. I remember, after take-off, we went back inside to watch it on my cousin's TV; and that's where we first saw the explosion. Immediately afterwards, we went outside to see for ourselves, and, sure enough, there was a dark cloud of smoke where, presumably, the shuttle exploded. Sad day.