hi,

after completing mechanical engineering, you may go for m.tech course in following streams, these are the most popular courses offered by Indian colleges:

M.Tech in Mechatronics

M.Tech in Automobile Engineering

M.Tech in Manufacturing Engineering

M.Tech in Robotics

M.Tech in Computer-Aided Design

M.Tech in Production Engineering

M.Tech in Industrial Engineering

M.Tech in Thermal Engineering

M.Tech in Industrial Engineering

space technology is related with aerospace engineering, however there is hardly any institute in India which offers m.tech space technology, however you may try for abroad university for pursuing post graduation after completing your b.tech.