Hey,

ISRO stands for INDIAN SPACE RESEARCH ORGANIZATION. It is one of the best organization and a dream place for people to get in if they have interest in space technology and science.

If you want to go for ISRO after 12th you need to sit for the IIST exam conducted by the organization and if you qualify in that exam you will be considered for admission.

There is no where written that 12th repeaters can't apply. You just need to have clear all the papers pf your class 12th and then you can apply.

Hope that helps.

Thank you