* Physics (classical mechanics, thermodynamics, fluid mechanics, electromagnetism, optics, relativity)
* Mathematics (calculus, linear algebra, differential equations, probability and statistics)
* Chemistry (organic chemistry, inorganic chemistry, biochemistry)
* Geology (mineralogy, petrology, structural geology, stratigraphy, hydrology)
2. Engineering
* Aerospace engineering (orbital mechanics, spacecraft design, control systems, propulsion)
* Mechanical engineering (design, materials, manufacturing)
* Electrical engineering (circuits, electronics, communications)
* Software engineering (programming, algorithms, data structures, operating systems)
3. Life sciences
* Biology (molecular biology, cell biology, organismal biology, ecology)
* Physiology (human physiology, environmental physiology, exercise physiology)
* Psychology (social psychology, cognitive psychology, human factors engineering)
4. Humanities and social sciences
* History (history of science, history of space exploration, international relations)
* Political science (international relations, space law, policy analysis)
* Sociology (sociology of science, sociology of organizations)
* Philosophy (philosophy of science, ethics, existentialism)
* Language (English, a second language)
5. Other skills
* Communication (public speaking, writing, interpersonal skills)
* Leadership
* Teamwork
*Problem-solving
*Decision-making
Astronauts should be well-rounded individuals with a strong foundation in mathematics and science, as well as a knowledge of engineering, life sciences, and the humanities and social sciences. They should also be able to communicate effectively, work well in teams, and demonstrate leadership and decision-making skills.