How long does a astronaut have to go college?

There's no single college degree requirement to become an astronaut. NASA astronauts typically have advanced degrees, often Masters or PhDs, in STEM fields (science, technology, engineering, and mathematics). However, a Bachelor's degree in a STEM field is usually a minimum requirement. So, the length of time spent in college varies greatly, from a minimum of 4 years for a bachelor's degree to potentially 7 or more years for a doctoral degree, plus any additional post-doctoral work.