There is nothing as such to become an astronaut. The major requirement is to pass the physical ,mental and certain other requirements like the type of qualification.

But if you want to go for engineering then it is better to be specific from right on as it will be a benefit to you.

Aerospace engineering is the primary field of engineering that focuses on the development of aircraft and spacecraft. There are other two branches. Aeronautical engineering and Astronautical engineering.

Avionics engineering is also similar, but it has a major focus on the electronics side of aerospace engineering.

There is no as such limit to the salary of an astronaut. It may range from Rs. 50,000 per month to a few lakhs per month. It mostly depends on the academic performance, achievements and experience.