– Xochielt Sanchez
Answer by Robert Frost:
Yes, a computer scientist in their twenties can aspire to be a NASA astronaut.
Swanny just returned from the ISS. He has a doctorate in computer science (although he also has a BS in engineering physics).
What your diploma says really isn't that important. It's what you have done that is important. Being an astronaut is a second career, not a first. The selection committee wants to see that you are an extremely high performer in whatever work you have done.
They want to see that you are a problem solver. They want to see that you have a strong work ethic. They want to see that you can take orders and work in adverse environments. They want to see that you can learn technical information quickly. They want to see that you are suited to the operations environment. They want to visualize you as a good representative for the agency and nation.
The most dependable routes to maximize the chances of selection are to have a first career as a high performance aircraft pilot, an engineer, or a medical doctor. Be all three for optimal chances. But there are many astronauts from more diverse backgrounds.
They want to see well rounded applicants – people that manage their time well and engage and excel in other endeavors. Learn to fly, learn to scuba dive, learn a foreign language, compete in triathlons, have adventures, travel, volunteer at charities, participate in your community or church or whatever is important to you that shows connection to people. Work on your public speaking skills.
Academic qualifications are important, and help with initial filtering, but soon it reaches a point where the selection committee has 600 resumes in front of them that all say "good degree from good school". You have to stand out as a unique, intriguing individual.
As an astronaut, you are never going to be assigned to write or debug code. But your experience in computer science gives you other skills that are useful. You learn to think about systems and variables. You can understand decision trees. You can solve problems. You can focus for long periods of time. That's all useful to the astronaut corps. But you need to be more than that.