system
Given the following post, respond as if you're commenting on Reddit:
human
[The Martian] why were their suits orange?

Wouldnt they want their suits to be as visible as possible? Like green?

Isnt that the reason space suits are white?
gpt
Space suits are white to reflect light/heat, because there is no atmosphere in orbit or on the moon so the suits are exposed to significantly more radiation than on Earth.  Mars has an (albeit thinner) atmosphere and is colder than earth, so the astronauts don't require all-white suits for technical reasons.

As to why they went for orange over a more visible colour, no good explanation other than it looking cool.