Rich Purnell slips and falls after he finds a way to rescue Mark Watney and tells his boss "I need more coffee." Donald Glover revealed in an interview that he slipped for real and just got up and continued to act, and the footage was retained in the final edits for the movie.
Matt Damon admitted that the scene where Mark was getting emotional upon hearing Commander Lewis' voice was genuine. The other actors had wrapped and gone home, and their pre-recorded voices were actually being played to Damon from inside his spacesuit. When Damon began to think about how his character had been all alone on Mars for two years, alongside how he was only hearing pre-recorded voices of his co-stars who had already finished their scenes, he began to tear up. Sir Ridley Scott was so impressed with Damon's performance, that he only did one take of the scene, which was used in the film.
NASA was consulted in order to get aspects of space and space travel, specifically in relation to Mars, with the most accuracy. NASA is federally funded, yet charges no one, including private for-profit organizations, any fees for use of and access to its archives and consultancy.
In the beginning, it is mentioned that a compromised space suit would cause decompression, giving someone about a minute to live. This is scientifically correct; contrary to popular belief, acute decompression in space or a planet with very low pressure like Mars does not cause the body to immediately explode or expand. Major effects include confusion, loss of consciousness and some subdermal bleeding, but it is generally agreed that a healthy human body can survive one minute in vacuum without life-threatening consequences.
A real potato farm was installed on the studio lot with potatoes in all stages of growth so they could be used for filming.