Mark Watney
The novel's protagonist. Watney is trained as a botanist and engineer, and is the only crew member of the Ares 3 mission not to make it off the Red Planet, following a catastrophic dust storm. Owing to Watney's patience, scientific expertise, and ingenuity, he is able to survive on Mars for many months—even growing his own food within the Hab (the small tent in which he lives). Watney is finally able, with NASA's intermittent help, to pilot a rover many thousands of miles to a different part of the planet, where he finds a rocket planned for a future Mars mission, and launches back into space. There, he meets the returning members of the Ares 3 crew, and begins his journey home.
Commander Melissa Lewis
Described as a tall, large woman, Lewis is in command of the Hermes aircraft. She is a Naval officer and is used to making tough decisions such as the order to evacuate Mars during a dust storm. But she suffers extreme regret at losing a subordinate. When she learns Watney is alive, she experiences guilt at having left him behind.
Lewis has a husband named Robert, and the two share a fascination with 1970’s music and television. Lewis’s disco music and her television files, left behind during an emergency evacuation, are Watney’s primary source of entertainment while on Mars. Lewis is not religious, and the text suggests she may be atheist or agnostic, but she has respect for other people’s beliefs.
Major Rick Martinez
Martinez is described as a good-looking man of Latino descent, and at one point in the novel he refers to himself as Mexican. A practical joker with a somewhat rude sense of humor and an extroverted personality, Martinez is the pilot responsible for controlling not only the Hermes aircraft but also Mark Watney’s launch vehicle. A military pilot, possibly Air Force, Martinez has outstanding skills as a pilot and takes his responsibilities very seriously.
Martinez has a wife, Marissa, and a young son named David. He and Marissa were high school sweethearts and they married young. He is a devout Catholic, and his religion is relevant to the plot because the small wooden cross he brings to Mars is left behind during the evacuation. It becomes one of several things Mark Watney uses to survive.
Dr. Chris Beck
One of the more introverted astronauts, Beck is the team’s doctor and EVA (space-walk) specialist. He is responsible for the daring rescue in which he exits the spacecraft on a tether and uses it to pull Watney in. He is not ordinarily a risk-taker, and generally errs on the side of caution.
Beck is shown interacting with his sister, Amy, but is not in a romantic relationship at the start of the novel, although he is attracted to Johanssen. He tries not to show his interest because of the ban on unprofessional conduct during the mission. But after the end of what would have been the official mission, while the Hermes is returning to Mars, he and Johanssen begin a relationship with the full knowledge and approval of Lewis and the rest of the crew. During the course of the novel, Beck becomes more willing to take risks.
Alex Vogel
The only non-American member of the Ares 3 mission, Vogel represents the European Union. He is a German chemist whose improvised bomb opens a hole in one of the spaceship’s doors so as to let enough air out to adjust the spacecraft’s trajectory. He is described as serious, yet Watney recalls bonding with him over a beer during training.
Because Watney is left behind on the surface of Mars, Vogel ends up having to take over much of Watney's duties aboard the Hermes while Watney performs many of the chemistry experiments Beck was scheduled to do on the surface of Mars. Each man has a lot of respect for the other's technical skills.
Vogel has a wife, Helena, who works as a teacher and lives in Bremen with their two children Eliza and Victor. He also has an aging mother who suffers from a form of dementia that affects her memory.
Beth Johanssen
Described as a petite, attractive woman, Beth Johanssen is the youngest and physically smallest person on the Ares 3 mission, although she still outranks Watney. She is a computer specialist, highly intelligent and with a strong background in programming and communications. She is responsible for decoding the hidden message containing instructions for an unauthorized course change. She is also responsible for overriding some of the Hermes spacecraft’s flight code so as to allow Martinez to perform the course change.
At the beginning of the novel, Johanssen is not in a romantic relationship. She has a mother and father who worry about her, but siblings are not mentioned. Later on in the novel, she begins a relationship with Beck.
Teddy Sanders
Teddy Sanders is a politically savvy, image-conscious man who is the administrator of NASA. As Venkat Kapoor’s boss, he has the authority to approve or deny requests for funding and resources. He is comfortable speaking in public, and is very conscious of the public relations aspects of everything NASA does. For example, to avoid the risk of having satellite imagery of Mark Watney’s dead body downloaded, Sanders denies all requests for Mars imagery for two months after the accident.
Sanders consistently tries to manipulate people by denying them access to information. He is the one responsible for keeping the news of Watney’s survival secret from the Ares 3 crew. He is extremely risk-averse, and vetoes the somewhat-risky Rich Purnell course change that had the highest probability of bringing Watney home alive. His lack of willingness to take risks earns him the hatred of most of his subordinates, who see him as a coward.
Annie Montrose
The director of NASA’s media relations, Annie is a polished, high-powered executive who comes across as very competent. She projects confidence and is well respected by everybody. Policy-wise she is often in conflict with her boss, Teddy Sanders. She favors open communications and is partly responsible for the global interest in Mark Watney’s continued survival. She bitterly resents Sanders’s manipulations and considers him a coward.
Bruce Ng
The director of NASA’s Jet Propulsion Laboratory, or JPL, Bruce lives in Pasadena, California. He is responsible for the organization that designs and builds the rockets required to launch resupply vehicles.
Venkat Kapoor
Venkat Kapoor is the head of Mars operations. He is in charge of not only the Ares 3 mission but other missions to Mars as well. He frequently finds himself at odds with other administrators at NASA, particularly Teddy Sanders. A basically honest person who is not fond of public speaking, Kapoor describes himself as Hindu.
Although he shuns the limelight, Kapoor is key in organizing the efforts to keep Watney alive and then to bring him home. He is comfortable with risk and does not approve of excessive, unnecessary secrecy.
Mitch Henderson
The flight director for Ares 3, Mitch is Venkat Kapoor’s immediate subordinate. He is a brusque, task-oriented individual who has very little regard for other people’s feelings. His colleagues dislike his personality but appreciate his willingness to take risks. He is responsible for finding a way to get details of the Rich Purnell Maneuver to the Ares 3 team, despite having the course change vetoed by Teddy Sanders. He is the first member of the team to stand up to Sanders. But as a result of his personality and mannerisms, Henderson irritates the Chinese scientists as well as his American peers.
Mindy Park
Mindy is a low-level analyst who works at SatCon. While looking at satellite images of the Hab, she realizes that Mark Watney is alive. She reports her findings to Venkat Kapoor, and is immediately the center of attention. This makes her uncomfortable at first, and she is intimidated by higher-ranking people such as Annie Montrose and Mitch Henderson. She is given responsibility for insuring Mark Watney receives maximum satellite coverage. This, for her, is a promotion. It also puts her in ongoing contact with relatively powerful people. She grows into her new responsibilities, and by the end of the book she becomes more confident and assertive and is no longer easily intimidated.
Rich Purnell
A physicist who generally calculates course corrections, Rich Purnell is the man who first has the idea of sending the Hermes to Mars by cutting its orbit short and looping back. It is a high-risk course-change, not because of the physics but because the Hermes will have to be resupplied with food. If the resupply mission fails all the astronauts will run out of food before the mission ends. Purnell is introverted and largely lacking in social graces.
Guo Ming
The Director of the China National Space Administration, Guo Ming has responsibilities similar to those of Teddy Sanders at NASA. He is responsible for interacting with the Chinese government in the form of the State Council. Clever and politically astute, he is a well-respected decision-maker.
Zhu Tao
The Under Secretary responsible for the Taiyang Shen and other rocket launches, Zhu Tao has a job description similar to that of Venkat Kapoor. He is the one who first has the idea of using the Taiyang Shen booster to launch a resupply after the NASA developed Iris probe is destroyed during an unsuccessful launch attempt. A very serious man not known for joking, Zhu Tao has bittersweet feelings about offering the Taiyang Shen booster, because he must sacrifice the years of research and development of a planned solar probe, which would have increased the scientific knowledge for all humankind.
