Thanks to reader Kevin Waite for a link to a fascinating space blog. He says "I think you'd find Wayne Hale's blog interesting (http://blogs.nasa.gov/cm/blog/waynehalesblog). He is ex-Shuttle Flight Director and now somewhere higher up in NASA. A damned good read.".
And it is. I'm being very, very good and not peeking (much) until end of play today, but I allowed myself one shot - and it makes fascinating and chilling reading.
One of the rules of spaceflight is that you mustn't kill large numbers of civilians by crashing your rocket into their town. Normally, this is taken care of by making sure you can steer away from trouble before abandoning ship - and normally, you can. Or you blow stuff up - the solid rocket boosters on the shuttle, for example, are under the control of the range officer and can be destroyed remotely.
But there is a 'black zone' during the shuttle's ascent where these options are not available. What happens then? Wayne Hale says it better than I can... and no, space flight isn't all jolly jinks in zero gee.