Indian Institute of Space Science and Technology is a Government Deemed to be University which is UGC approved and NAAC accredited. The institute has association with the ISRO. Now no course is there which can be done after BSc Physics course, although, if you complete the MSc in Physics course after that you can do the MTech or PhDcourse at IIST by qualifying the GATE examination.

For more information regarding IIST consider the link below:

https://www.careers360.com/university/indian-institute-of-space-science-and-technology-thiruvananthapuram

For the official website consider the link below:

https://www.iist.ac.in/admissions/postgraduate/regular

I hope this helps. Wish you a great eve!