Hello....

ISRO is not as much into Space Research as NASA or ESA so it is not possible to become "space scientist".
Simply "scientist" ,"Rocket scientist",or engineer will be better post to get in ISRO.


For working in ISRO best way is to become an engineer because engineer's are recruited as Scientist SC in ISRO.

Two paths in this way:
1) IIST: Attempt JEE Mains & Advanced after 12th and try to get an admission to Indian Institute of Space Science & Technology (IIST). This is administered by ISRO and all passouts with more than a certain cut off GPA get directly absorbed in ISRO.

2) ICRB: Complete engineering from any accredited institution in Mechanical/Aerospace/Electronics/Civil/Refrigeration & AC/Computer Science and apply for the ISRO Centralized Recruitment Board (ICRB) recruitment procedure.

For further information you can visit this link:-https://engineering.careers360.com/articles/isro-recruitment

For any further queries feel free to comment.