This is not through gate 2017 or 2018.
ISRO has their own procedure for selecting students for scientific posts.
The minimum eligibilty criteria is you should have 65% or if cpi then you should atleast 6.84 cpi,they also ask for students 10 and 12 percentage.Now this is minimum qualifying criteria.
After this ISRO do a shortlisting ,after that students get call to attend written test conducted by ISRO .
After passing the written,students are called for interview and then the final merit list is prepared.
The total no of vacancies for CSE students are 10 for the recruitment happening in the month of december.