Dear aspirant ;

The best college that provide astronautical engineering (or) aerospace engineering is IIST Thiruvananthapuram. This is the primary institute for joining ISRO. Almost 80 percentage of total candidates who join ISRO come through IIST system at Thiruvananthapuram. This is the most recognisable institute in the field of space in India.

To join IIST you'll have to score well in JEE advance. They consider your JEE advance mark to get an admission here.

Hope this helps and all the best!