Hello,
You can't go for masters degree with out have UG degree in hand. No college will accept you directly from intermediate for a PG course. That is not the learning path and not possible for any stream or course.if you want to go for space science then go for aeronautical or aerospace engineering else join IISER accepting institutions where you will work in different research based projects. If you can choose UG course for space engineering then you can do Masters in space science.
For short path, choose aeronautical engineering and get admission at IIT. If you work hard then you can easily get job at ISRO or its branch offices.
With some years of work you can also collaborate with international space station for skilled work.
Hope it helps!