ISRO is a place where the concept of Software Engineer, Electronics Engineer or Non-Engineer does not exist. You work as individual and as a team (both happens). As a software engineer or a person with role of software development you may have to deal with different types of projects involving coding on embedded systems, coding using VLSI, coding on C/C++, coding on java,web development, coding on perl, coding on python and list is very big. There is no hard and fast rule which language is to be used and why other language cannot be used. Its all developer choice or at times choice forced on him. The tasks revolves around data ingestion, data processing, data archival, data security, payload interface, payload commanding, satellite telemetry, satellite commanding, Monitoring control of equipment’s, vehicles, satellites, subsystems and so on and on.. List is endless.
It largely depends on which centre you work for, if you are working on launch based centre, your work would be primarily about launch vehicles and related development.