don pettitte replaced a prime crew member.e a back-up option eva, we've exercised our back-up crew return mode, and we've used a back-up option on the entry control mode so you can see one of my lessons learned is back-ups are good. [laughter] back-up options help reduce risk. when you're not sure what's going on or even when you think you are sure and the consequences are high if you've made an error, having a back-up option can help you through that system, that process, that problem. well, um, after i got back i had six months of rehab. came to headquarters for about four months which is a lot harder than a ballistic entry working in washington was a lot tougher -- [laughter] than any of that training, anything. i really, um, i empathize with the folks that work here and the difficulties that they go through every day. and it was good for me to experience that. but it was also great to get back with the shuttle team who, by this time, were about a year into dealing with sts-107. my job was as the director of flight crew ope