Really good composition idea! The shirt actually detracts from the picture though - the "blast off" is so bright that it takes your focus from the subject matter. The hat is appropriate due to the awful weather outside, and the use of ambient lighing was a great idea. I like the pose and use of the backpack as a prop. The wood is beautiful and the window view is appropriate. You could have cropped out the top of the picture - since it is just dead space to keep the focal point on your subject.
Nice candid appearance. Crop out top and bottom some would be better, and allow image to be larger so that the NASA t-shirt is more obvious, as I missed it on the first viewing.