Our best source of knowledge about astronauts is obviously Hollywood. With at least one space movie every year, we know more pseudo-science about space than we know the actual science.
But sometimes, Hollywood does get it right, and if you were observant enough, you would have noticed that sometimes the astronauts dress up in Orange spacesuits, like this –
And sometimes they are in white spacesuits like this –
Which has a reason behind it. I will cut the chase and get straight to the point.
The orange spacesuits are actually Advanced Crew Escape Suits (ACES).
They are specifically used during launch and re-entry back into Earth’s atmosphere. The Orange spacesuits have built-in survival gear, that can be useful if an accident occurs during launch and re-entry.
Also, the orange color is easily visible when the ground crew is doing a search and rescue operation.
The White spacesuits are Extravehicular Activity(EVA) suits.
They are built specifically for spacewalks and because they are white, they reflect most of the sun’s radiation. These suits are built for space survival, rather than emergency survival. It has a cooling system, a urine disposal bag, air filtration system and a tough shell to protect astronauts from getting peppered by micrometeoroids in space.
To summarize it –
Orange spacesuit – Only during launch and re-entry.
White spacesuit – Only during spacewalks.