The Question and Answer section for Into the Wild is a great resource to ask questions, find answers, and discuss the novel.
Walt worked for the Jet Propulsion Loboratory. He worked with the space mission.
You need to submit each of your questions one at a time.
This is difficult to say. It is stated that Chris came to some kind of epiphany in the Alaskan wilderness: he needed other people. Perhaps Chris might have been less inclined to take such silly risks and romanticize a life that is extremely harsh...