Hello Dear,

For becoming an astronaut you have to fulfill these requirements

1. All applicants should have earned at least a Bachelor's degree in engineering, biological sciences, physical sciences, or mathematics from an accredited university. (Preference can be given to applicants with either a Masters or a Ph.D.)

2. Applicants need to meet NASA physical standards, including:

Distant visual acuity  :   At least 20/100 or better uncorrected that is correctable to 20/20 each eye, (Color blindness is usually grounds for disqualification.)

Maximum blood pressure: 140/90,

Height range: Between 62 and 75 inches for Astronaut Pilots and between 58.5 and 76 inches for Mission Specialists,

Meet the hearing requirements, and Pass the psychological screening.

3.   Applicants for an Astronaut Pilot position should have flown at least 1,000 flight hours as the pilot-in-command of a jet aircraft.

The selection process for the Astronaut Corps is very competitive because there are many more people who apply to the program than there are available positions. Thus, it is extremely important to be able to exceed the basic requirements wherever possible.

Finally, once a person is hired as an Astronaut Candidate, they will undergo a two years training and evaluation period to determine whether they are qualified to become an actual astronaut. For example, candidates will need to successfully complete the U.S. military water survival course and become SCUBA qualified. They will also need to be able to demonstrate that they can function in high pressure (hyperbaric), low pressure (hypobaric) and microgravity environments.

Best of luck.