Indian missiles and weapons systems are mostly derived from Sanskrit scriptures.
In Sanskrit, "Su" means good or auspicious and "Darshan" means vision translating Sudarshan to Auspicious Vision. As per ancient Hindu scriptures, one of Lord Vishnu's weapon is a Sudarshan Charkra and it must've something to do with it too
Haha, you can teach me about Hindu scripture as Much as you want but please don't explain Sanskrit to a Bengali person like that. It is actually much closer to Sanskrit than Hindi. word for word 'Su Darshan' means the same in Bengali. I.e. nicelooking. (I double checked) But that wouldn't make sense for a weapon name. So, it is probably has to do with weapon name in Hindu scripture.