Greetings!

To get into isro before graduation: You need to crack IIT JEE and get into IIST, there you need to maintain a good CGPA and then you need get into isro as researcher.

To get into Isro after graduation you need to follow the following steps:

1. Appear for Isro exam, Isro conducts a written test of their own in the month of April every year, you need to qualify that first, all the process of registration is online only.

Eligibility for Isro:

You have to complete B.E/B.Tech or a equivalent qualification with first class with an aggregate minimum of 65% marks or CGPA 6.84/10 (average of all semesters for which results are available). Minimum of 65% marks or CGPA 6.84 in section B alone for candidates with AMIE/Grad IETE qualification.

I hope this was helpful. Thank you!