Near the end of The Martian movie we see Mark Watney shirtless, and his body appears to be bruised. What is the cause of these marks? I thought it might be from scurvy or some other malnutrition.
When Mark takes the suit off in the ship at the very end of the movie everybody complains about his body odour.
He says " I haven't had a shower in a year".
Having been in a similar situation ( with no acces to water for a long period of time ) I can tell you that his marks look a lot like something you get from not enough personal hygiene combined with a poor diet.
I was struck by the skin lesions/rash as well, and have been looking for an explanation. I suspect it had to do with prolonged exposure to radiation. The Mars atmosphere is very thin, 100 times less dense than Earth's. An astronaut wouldn't have the same protection from solar radiation that we enjoy on Earth.
He appears to have pellagra, which is due to deficiency of niacin (Vitamin B3) or the amino acid tryptophan, neither of which are present in sufficient quantity in potatoes to prevent this micronutrient deficiency.
Could be 'bed sores' from living in a pressure suit for as long as he was forced too. Staying outside the transport so it could charge up might make for all kinds of marks on his skin.
The lesions/rashes were shown at the same time his much thinner body was shown after 7 months or so.
This could have been due to prolonged diet of boiled potatoes without any source of Vitamin C and other vital ingredients.
He broke a couple ribs due to the 12G's he experienced during the MAV ascent. Being yanked along by a tether with Beck didn't help matters.
protected by Community♦ Dec 24 '15 at 12:54
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?