Hello,
You do not have to work for NASA or move to the United States to be a space scientist. There are professional astronomers and space scientists working for observatories and universities in India, like the Indian Institute of Geomagnetism. Some of these scientists even study the Sun and the Earth's magnetosphere, just like the Solar Week scientists. A few of my co-workers have attended space science conferences in India and have collaborated with Indian scientists on journal articles.
Whether you eventually decide to pursue a scientific career in India, or come to the United States to work for NASA, you should take as many math and science courses in school as you can. You should also plan to attend college and possibly graduate school to obtain an advanced degree in a field like physics, astronomy, or mathematics. If you are not very good at math and science, there are other jobs you can do related to space exploration. Space scientists often need help from technicians who build electronics or maintain equipment, computer programmers, and even machinists.
Kris