• NASA astronauts wear white suits, since white is the colour that reflects the most sunlight in space, and protects them from cancer-causing solar radiation.
  • Other space agencies, like in Russia and China, use white for the same reason.
  • When they first launch though, astronauts wear orange instead, since the bright colour makes it easier for them to be spotted and rescued in an emergency.
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NASA didn't always have white spacesuits. Their very first manned spaceflight, Project Mercury, featured silver suits, but none of those astronauts explored the vacuum of space. And that's the key because out there, spacesuits must be highly reflective. And the best colour for that isn't silver, it's white.

White reflects radiation most effectively while in outer space.

On Earth, our atmosphere shields us from 77% of the sun's radiation. But astronauts in space don't have that natural shield, making them vulnerable to blistering temperatures, severe sunburn, and even cancer-causing cell damage.

So, to combat that, they wear white suits that reflect the sun's harmful radiation. It's just like how painting a wall white keeps the room cooler than a dark colour because lighter paint absorbs 35% less heat.

White EVA suits aren't the only garment in an astronaut's closet. When heading into space or coming home, NASA astronauts wear a bright orange suit similar in colour to the safety vests Air Force pilots wear, and it's for similar reasons because that loud orange stands out against the blue ocean and sky and is perfect for attracting attention, so if there's a malfunction during landing and astronauts have to abandon ship, so to speak, they need to be easy to spot for rescue crews.

That's why orange was the colour of choice for missions like Russia's Vostok program as well as current ISS launch and re-entry suits.

Nowadays we have more sophisticated ways of locating astronauts in need of rescue, like GPS trackers and transponders, so space agencies are now free to get creative with their colour choices.

NASA and other programs are already starting to use other colours like deep blue and mustard yellow. And in the future, they could look a lot different because NASA is heading to Mars. It will be the longest crewed space mission to date, taking as long as three years from start to finish, and during that time, astronauts could suffer from boredom or depression. That's where colourful spacesuits could be useful.

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