The opening of this novel is spectacular and it gets better as it progresses. The sheer amount of thought put into it is mind blowing, and it is (or at least, it feels like) real science rather than sci-fi. You can find huge amounts of calculations and scientific speculation, that make this novel an excellent hard Sci-fi. 
 BUT, halfway in, the plot begins to get funny. 
 Countless random disasters happen, and the author throws outrageous hurdles at the protagonist. There is no need to worry, however, because our unstoppable heroes find such ridiculous solutions for impossible problems that the narrative and the plot start to reek of a superhero comic books instead of hard sci-fi (especially considering the ridiculous ending of the book). 
 Had the author removed some of the less realistic and more fantastical elements of the plot, and stuck with a more stable course, the novel would have been a masterpiece. Survival on Mars is exciting enough. There was no need to add ridiculous events such as the failing of the airlock, or the very unbecoming ending of the novel. By focusing on a more realistic plot line, this novel could have been exceptional. 
 But now, the first half is great, but the second half is not very plausible, and the finale is just 'space-cowboys'. Because of the first half, however, I recommend it to every sci-fi fan.