The bottom portion of the MAV doesn’t produce oxygen, but it does collect CO 2 from the Martian atmosphere and stores it in liquid form. It does this as one step in producing rocket fuel used ...
"The Martian" succeeds in doing so ... it cannot topple a heavy Mars Ascent Vehicle (MAV). However, the dust storm is a great fictional catalyst that triggers Mark's survival story in space.
In "The Martian," astronaut Mark Watney is screwed ... communications systems were located in the Mars Ascent Vehicle (MAV), which the rest of Watney's crew took with them when they left Mars ...