The Aether has explored K-23, a moon of Jupiter that’s a-ok for human colonization, and is returning home with the results.
Providing them with the data to slingshot around the Earth and return to K-23, it’s assumed that our lonely, and terminally ill astronomer finally passes on after finally “meeting” Sully (Felicity Jones), one of the astronauts on the Aether.
It’s a moment that poignantly closes out Augustine’s story, as Sully means more to him than he could have ever known.
With a treacherous journey to the stronger antenna at the Arctic base complete, Augustine successfully warns the Aether’s crew that they shouldn’t return to Earth.