Hello Chanchal,

No, it is not mandatory to score the highest in 10th standard, for becoming an astronaut.

You need not be a topper at school for this.

The basic requirements are a bachelor's degree in engineering, biological science, physical science, computer science or mathematics, followed by three years of professional experience (or 1,000 hours of pilot-in-command time in jet aircraft).

Although, it takes many years of education and experience to meet the basic qualifications. Many people aren't accepted on the first try, either, requiring them to learn more to be better prepared for the next try. Even then, only a small percentage of applicants become astronaut candidates, making it a hard job to get.

Hope this information helps you.

Feel free to ask more questions.

Have a good day!!