I just saw the interview of Andy Weir and was blown over by his intellect and his hugely attractive persona as well as his talent as a writer. One of the words he used about the problems, which arose one after the other and often with the latest one one due to part of the solution to the previous one, was "cascade." It was that cascade effect which kept me reading with rapt interest even though most of the science was beyond my unscientific mind.
As I read about his effort to produce water at first I thought to myself, humans have been unable to create water on any kind of scale. Then I saw that it required a dangerous fiery explosive situation for him to form 50 liters of water. I wonder if that is actually possible as he related it or if it was part of the fictional liberties he took occasionally. Andy Weir said in the interview that one astronaut who read his book informed him that on one occasion if the process had been carried out as he wrote it that Mark would have been roasted.
Also, the way Weir described his change in the narrator from first to second person made perfect sense, because it widened out the emotional charge for the reader. Instead of identifying with the protagonist and sharing his terrible difficulties, the second person narrator enabled us empathize with the officials trying to help him and to see what was happening outside Mark's situation. His change in narrator was able to bring in the world. Excellent book.