This is Chapter 15 in Volume 3 of A Place Further Than the Universe manga.
They go on an ice operation, which is the harvesting of shaved ice to bring home with them. Shirase gets to meet some penguins up close. On the day of departure, Shirase makes a farewell speech, wishing luck to the team that will stay through the winter. As the ships sails off, the girls see the aurora for the first time.
The separate at the train station, and go home to their families. Kimari texts to Megumi, who is on her own adventure in the arctic.
This chapter is based on We'll Go On Another Journey Someday (Episode 13) of the anime.