system
Given the following post, respond as if you're commenting on Reddit:
human
[The Martian] What and where is the Descent Vehicle?

I haven't read the full report, but I've studied the documentary a couple of times and I cannot figure out how did they get to the surface. 

I know that they sent the MAV, HAB, Rovers and everything else ahead of the crew, and the crew got from Earth to Mars on the Hermes and from Mars to the Hermes with the MAV, but how did they get from the Hermes to the Martian surface?
gpt
The MDV (Mars Decent Vechical) is a hydrazine powered landing craft. It was sent before hand and left in Mars orbit, where *The Hermes* docked with it. The crew then transfered over and used it to land on Mars in Acidalia Planitia. Later, Astronaut Mark Watney used the leftover hydrazine to make water for his potato farm.