I am interested in space sciences.

Thats a very good option for future.
There are various bramches of space science like Astronomy, Astrophysics, Cosmology, Stellar Science and Planetary Science etc.
IIST is the best college that one can be in for space science. The entry in this id again dependent upon the marks and rank in JEE.
The following are some other  best colleges that provide education in these feilds:

• Birla Institute of Technology,Jharkhand
• Aryabhatta Knowledge Institute of Science and Technology,Bihar
• Indian Institute of Space Science and Technology Thiruvananthapuram, Kerala
• Sri Venkateshwara University , Andhra Pradesh

Hope you get into this field.
All best Best.