[The space station departure ceremony] can be very emotional. You're seeing good friends for the last time for several months. Some of them are coming back to the Earth to smell again what trees and grass and the Earth smell like and taste Earth food and see family and friends. And so they might be very excited and happy, but they try not to look too excited and happy because there are other crew members who are leaving their family and friends for four months…

Astronauts in general try to have subdued emotions. There's not enough space in the workday to be emotional. But at these ceremonies, when you're shaking hands and hugging each other and saying goodbye to friends, both Russian and American… it can be a very emotional time.