The Earth is a beautiful planet. The space station is a great vantage point to observe it and share our planet in pictures. It makes you more of an environmentalist.

This was exactly what I experienced in space: immense gratitude for the opportunity to see Earth from this vantage, and for the gift of the planet we've been given.

And in that moment, I was hit with the realization that this delicate layer of atmosphere is all that protects every living thing on Earth from perishing in the harshness of space.

Leaving the space station was bittersweet - I had been there for a long time and looked forward to leaving, but it is a remarkable place.

The ride to orbit was impressive, as it always is. But once I got on board the space station, it really felt like I was visiting an old home; it felt very comfortable.

We do a lot of science on the space station. Over the course of the year, there'll be 400 to 500 different investigations in all different kinds of disciplines. Some are related to improving life on earth in material science, physics, combustion science, earth sciences, medicine.