Mars’ atmosphere is composed mostly of carbon dioxide, which accounts for 96% of the total. The rest of the atmosphere is nitrogen, and argon, with very small amounts of oxygen. Mars has a very thin atmosphere; it is 200 times less massive than the atmosphere on Earth. It would not be possible for people to breathe on Mars - not only is the atmosphere very, very thin, there is not enough oxygen. However, it is thick enough to allow a parachute to slow an incoming spacecraft. Mars also has clouds and dust storms, as visible in the pictures below.