Mark Watney
A Botanist and member of Ares III, Watney is dedicated to going to outer space and exploring signs of life there. He is notable for being easygoing and amicable and having a sense of humor. He was also selected to take part in work exploring plant life on Martian soil to test for the possibility of future colonization.
Melissa Lewis
The Commanding Officer of the mission, she is the one to leave Mark behind in order to get the crew to safety. She has a degree in oceanography and is a geologist, thus making her the ideal choice for being assigned leader of Ares III.
Theodore "Teddy" Sanders
NASA's Chief Director, he is committed to this mission and is disappointed with the loss of Watney. However, once he realizes that Watney is in fact alive, he decides to not inform the rest of the Ares III crew as he does not want to distract them from their mission.
Annie Montrose
She is assigned as the director of media relations for NASA and has to deal with the media repercussions after Watney's supposed death. However, upon realizing that he has survived, she and Teddy both deal with informing the public of his survival; she tried to limit the PR damage as much as possible.
Vincent Kapoor
Being of mixed Indian and African heritage, he has made a name for himself as NASA's Director of Mars Missions and is Mark's first point of contact after he is discovered to be alive. However, he is reluctant to inform the rest of the crew of Mark's survival.
Mitch Henderson
Hermes flight director and leader of Ares III, he feels the brunt of responsibility for Mark's supposed death. He is most adamant that the crew is informed of his survival but he is hushed by Kapoor and Teddy.