Science

After class 12th, you can pursue aerospace engineering, aeronautical engineering or courses related like B.Sc in physics and then M.Sc in space technology. You can also pursue courses specifically in telecommunication or space technology or satellite communication etc. There are different courses available. You can also pursue B.Tech in mechanical engineering and then M.Tech in space propulsion systems. This course will help you in entering into space. Also B.Tech in electronics and telecommunication and then M.Tech in satellite communication will be helpful.

It is not a problem, combining all these pursuits. Even after joining service, you can complete your research and submission of the thesis. Such instances are in plenty. Go ahead with whatever you desire.

It would better if he can pursue Ph.D after completing his M.Sc. He can get better career opportunities.
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You can opt for M.Sc in botany, zoology, biotechnology, etc.

B.Tech in CSE is the course for you if you are looking for the detailed study in the hardware and software field. Top colleges for this course are:
1. Vellore Institute of Technology, Tamil Nadu
2. IIT
3. UTM, Shillong
4. BITS, Pilani

Basic maths is there in every engineering course. Integration, differentiation, statistics, and progression are the basic concepts which are there in the 1st year of almost all disciplines. These concepts are easy to learn.

You can do pursue B.Sc in biochemistry, biotechnology, genetic engineering, environmental science, biochemistry, life science, general science or B.Sc (Hons) in chemistry, biology, botany, zoology, maths, home science, etc.
You can opt for the professional course like hotel management. You can also pursue law.