When the U.S. military selected the first class of astronauts in 1959, it sought military personnel with engineering training and experience flying jet aircraft. In 1964, NASA began searching for scientists with a doctoral degree in medicine, engineering or a natural science such as physics, chemistry or biology. After several decades of space missions, including the first moon landing in 1969, NASA has modified its astronaut requirements. For example, today applicants must have a master’s degree in a science, technology, engineering or mathematics, commonly referred to as STEM. They can also meet requirements with two years of work toward a doctoral program in a related STEM field or a completed doctor of medicine or doctor of osteopathic medicine degree. Here’s a look at where the most current and former NASA astronauts attended college. This list, compiled using data supplied by NASA, includes undergraduate and graduate alma maters and excludes postdoctoral programs.