The NYTimes shared an article written by the astronaut. One of the unexpected findings was the importance of keeping a journal while in isolation.  You can read “I Spent a Year In Space, and I Have Tips on Isolation to Share” on the New York Times (you may need a guest log in to view the content).

His tip on journal writing is about mid-way into the article (bold added for emphasis):

NASA has been studying the effects of isolation on humans for decades, and one surprising finding they have made is the value of keeping a journal. Throughout my yearlong mission, I took the time to write about my experiences almost every day. If you find yourself just chronicling the days’ events (which, under the circumstances, might get repetitive) instead try describing what you are experiencing through your five senses or write about memories. Even if you don’t wind up writing a book based on your journal like I did, writing about your days will help put your experiences in perspective and let you look back later on what this unique time in history has meant.

Turns out you CAN be a rocket scientist. All you need is your journal!