I am not part of Stellar team, but was following Stellar since they forked from Ripple (and also Ripple until that point). My take on this is as follows:
Since the beginning, Stellar have a really cute comic to explain how it's consensus protocol works. The main point was derived from problem of what kind of interstellar blockchain is needed to work not only for us, but also for and together with aliens out there. That also implicitly crossed out proof-of-work consensus due 51% attack if aliens with supercomputers would come by.
Therefore Stellar (aka stars) is just a pun on it's strength that it can work out nicely in interstellar conditions where you have lots of different aliens with varying computing power and interests. Kind of analogy to the so called "superpowers" down here on earth.