Hello,

You can obviously go for M.tech in aerospace engineering after a B.tech in CSE, infact there will be a lot of growth considering you will hail from a software background and space technology nowadays is advancing on a global level which requires sharp skills and a good hand at coding, data structures and algorithm.

If you are interested in research domains as you mentioned you can aim for IISc as it is the best institute for research in the country and around the world and has also featured in QS and NIRF rankings.

GATE with a under 200 rank(GEN) can fetch you desired branch in IISc and you will have an assured and accelerated career growth there.

Good Luck, Hope it helps!!