If u plan to make it to NASA, and u happen to be from India, doing Aerospace/Aeronautical Engineering from the IITs would be the best. I shall sketch a plan to reach your goal. Your goal is to be employed in NASA. Do your B.Tech Aerospace/Aeronautical Engineering in flying colors, maybe top in the batch. Take up a fellowship program for MS and Ph.D. at top Aeronautical/Aerospace university in America, under a top guide. Publish technical papers of high quality. Be a member of the Aeronautical Society of India, and also of America. Focus fully on your research programs MS and Ph.D. Try to study and discover something unique, something important in your research. Your guide, and Head of the Department and other senior professor would be happy with u. U would be spotted by the NASA, and an attractive job package would be offered to u.

For this to happen u must be fully involved in Aerospace, fully dedicated and devoted to your research project. Make education a religion, ritualistically do your research and the fellowship program. Sacrifice everything to realize your goal. Be simple, and if possible be a celibate. Nothing is impossible if u have a burning desire to achieve the most difficult goal, and u r willing to pay for it. We have a famous Ex-president who tried to do something like this. A.P.J. Kalam had done Aeronautical/Aerospace Engineering from MIT chennai. He achieved the impossible at that time, by launching the SLV-3, and making India the fifth country in the world to have space launch capability. He successfully designed, fabricated and tested missiles like Prithvi, Trishul, Nag, Agni etc. to become the Missile man of India. He carried out the Nuclear explosion for peaceful purposes and made India the sixth nuclear power in the world.

Everything is possible if u r ready for hard work and sacrifice.