Hello!!

The minimum eligibility criteria is that you must have qualified B.E/B.Tech or equivalent qualifying degree in first class with an aggregate minimum of 65% marks or CGPA of 6.84 on a scale of 10.The average of all semesters will be considered for the purpose of CGPA .Based on the academic performance and bio-data,initial screening will be conducted to short list the candidates for the written test.For more details regarding the selection and short listing process,visit the below given website

Yes,the cutoff mark will vary based on the category and also the domain of engineering of the candidate.

For Computer Science,the Maximum marks of the exam is 234 and the cut-off for general category is 173.(2017 exam cutoff)

https://engineering.careers360.com/articles/isro-recruitment