FAQ

Orbital rendezvous is not an inflexible science when it comes to emergencies like the one depicted in The Martian. The Hermes would have been in a stable, circular orbit, and the MAV would have had a pre-determined flight plan to establish a compatible, lower circular orbit, followed by additional maneuvers to create an intercept and rendezvous. There are videos on YouTube and even space simulators that allow you to even perform maneuvers to see how it all works.

No, because a day on Mars (or a "Sol") happens to have almost the same length as a day on Earth. An Earth day is 24 hours on average (there are slight seasonal variations), while a Sol lasts an average of 24 hours and 37 minutes. Human beings have an intrinsic circadian rhythm, i.e. a biological daily clock which is normally around 24 hours and 11 minutes. This means that technically, human beings are slightly out of synchronicity with the rotation and day-night cycle of the Earth. However, a human biological clock can be "reset" by certain factors like (day)light quite easily after 24 hours, so in practice, this does not cause problems. In fact, experiments have shown that humans can adapt to slightly shorter day-night cycles (23 hours and 30 minutes) or longer (24 hours and 36 minutes) with no problems. So, adapting to the Mars' days and nights would not be a problem for Watney.

After the storm that separates Mark Watney from the rest of his crew early in the story, he finds himself in the unfortunate circumstance of being impaled by a piece of the team's antenna. When patching himself back up, part of his regimen involves the use of antibiotics to protect against infection. But does he need an antibiotic? There are no bacteria in space, so is an infection something he needs to worry about? The short answer is yes-plus, its simply better to be safe than sorry. There may be no bacteria in space, but bacteria still survive in three places that could contribute to a wound infection: the antenna itself, Watney's space suit, and Watneys own skin. Read a full explanation here.

Because the Ares missions are so large and complex, NASA sends some of the elements of the mission to Mars before the crew actually arrives. The MAV was one of these elements. While it waits for the crew it produces fuel and other elements needed for the mission.

No, but there are scenes that are shown during the beginning of the credits. See here or here for more information.

The additional scenes of the extended cut fit in seamlessly into the tone of the movie. There are more lighthearted moments with a variety of characters. You won't find anything substantial but if you liked the theatrical version, the extended version won't worsen your opinion. An interesting side note is that Scott apparently used the release of the longer cut to potentially restore some PG-13 censorship as some dialogue extensions deal with a vulgar term that if you look it up would be a clear taboo for the rating.