Day has written many articles in space magazines including "Spaceflight", "Quest", "Novosti Kosmonavtiki" and other publications such as "Space News". He is an associate editor of the German spaceflight magazine "Raumfahrt Concret". Day published the book "Eye in the sky" about the CORONA spy satellite program, and was investigator for the Columbia Accident Investigation Board, where he focused on the policy, budgetary, managerial and institutional causes of the Columbia accident.