NASA Building Emergency Roller Coaster for New Shuttle

NASA already has an emergency egress system from the orbiter launch pad - the astronauts jump into a cage and ride it down a cable to a safe distance away. The astronauts have to train on the sytem and actually ride it down befoe every launch. The whole system depends on time, though - if you know you are going to have some trouble, you could ride the system down. The problem with time, though, is that once you light the SRB's, they are leaving the launch pad - whether or not the orbiter remains attached is immaterial. Once the SRB's light, you pretty much don't have time to get out of the cockpit and into the cage. That's why everybody really sweats a lot from T-nine minutes until about T+nine minutes - you are pretty much screwed if anything bad happens. NASA has experimented with various systems for bailing out of the orbiter after lift-off, but as Challenger demonstrated there is precious little time during a catastrophic failure to do anything - by the time anybody could interpret the telemetry, the event was pretty much over. There were other issues during that event, but Chuck Yaeger pretty much covered it in great depth.