MESA, a piece of software referenced in this article, is a pretty incredible system. (Even referring to it as software underplays the extent of its community and impact.)

Many people are involved in MESA and Bill Paxton was always quick to point out the many new folks that worked on it, but this article does a great job of celebrating his impact:

https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist

It's amazing to me that he went from being the voice on the other end of the Mother Of All Demos to having such a major impact on stellar astrophysics during his "retirement." He passed away in 2025.