Let's take flight simulation as an example. If you're trying to train a pilot, you can simulate almost the whole course. You don't have to get in an airplane until late in the process. ↗
When I write I simply follow my heart. And my flights of fantasy. It is not done with a conscious effort. I'm continually inspired and write reflexively. ↗
The first two missions have some test objectives, some new capabilities that we're going to try to develop on orbit to possibly be used on later flights. ↗