Hello Priyanshu,

There is a certain procedure to join ISRO after completion of Bachelor of Science in Chemistry. 

In general, National Remote Sensing Center of ISRO issues official notification for filling up several vacancies every year and posts may include, 

• Fitter 
• Electrician 
• Electronic Mechanic 
• Machinist 
• Plumber 
• Motor Mechanic 
• Scientific Assistant , etc

As you are done with Bachelor of Science (B.Sc) in Chemistry from a recognized university you may apply for the post of "Scientific Assistant" and desirable knowledge in computer programming.

Hello,


ISRO conduct a written test every year to recruit students. The exam is generally held in the month of April every year through its central recruitment system called ICRB (ISRO Central Recruitment Board) in various stream namely Mechanical, Civil, Electronics and Computer Science. Candidates with aggregate of more than 65% marks are eligible for the job.
Applicants are required to take a written exam consisting of 80 multiple choice questions(MCQ) related to your stream. On the basis of this exam, the selected applicants are then called for an interview which decides the final selection of candidates for the post of Scientist/ Engineer.


I hope this helps.