Required option to become Astronaut after 12th

Tell me which course should I have to opt for after completion of 12th to become Astronaut, please provide details???

[Quick Sam]

Here are the required details to become Astronaut:

Qualification
Bachelor's degree in engineering
Biological science, Physical science, Computer science Or Mathematics

Then you need to obtain any one of the following degrees from renowned institutes like IISC or IIT.

Phd (Astrophysics)
Phd(Geophysics)
Phd(metaphysics)

After graduation, you can appear for the entrance exam which is held by the NASA for the recruitment of scientists, Astronauts etc.

You may also find employment in ISRO

There are many openings in ISRO which is conducted for the recruitment of scientists, engineers .

Inorder to join ISRO, you need to clear joint entrance exam by IIT's.