The spacesuits NASA currently uses and has used in the past are very massive. They weigh about 220 lb on the Earth. On the Moon, the same spacesuit only weighs about 35 lb. The spacesuit weighs 84 lb on Mars. Weight isn't the only reason why the colonists couldn't use a standard NASA spacesuit.
Human bodies produce a lot of heat.
Spacesuits keep an astronaut warm by using many layers of insulation to trap the astronauts body heat. The insulation works so well that even in space the spacesuit has to have a cooling system. Without one, the astronaut would overheat. The cooling system consists of water circulated by a pump, and the loss of heated water to space from the backpack on the suit. Also, the amount of heat an astronaut needs to keep on the Moon or in orbit around the Earth is MUCH more than what a colonist would need on Mars.