eli5: Why is white so prevalent in spacecrafts and equipments?
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It reflects light. This is important for two reasons: first, most of space is dark, and a dark object against a dark background is particularly hard to see.
Second, dark things absorb light and get hot — which you probably have noticed wearing a dark shirt on a sunny day. On Earth, a lot of the light is blocked by the atmosphere, and you’ve got air to cool you and carry heat away – but, in space, it’s really hard to get rid of heat. It’s like being in a thermos — there’s no air to transfer heat to and carry it away. So, in space, you’d just be absorbing more and more heat until something is very hot.
It’s also true that we tend to use on the inside of spacecraft so that they don’t look so cramped, and it’s a bit easier to see small objects and things floating about in the ship (you want to keep it tidy so that equipment doesn’t get damaged or something get sucked up your nose).
You might have heard that space is cold, which is true with a huge caveat. Since there is no air there is nothing to conduct the heat so you can not feel the cold. This is a problem because the spacecraft is above the atmosphere and above the clouds so it is always in bright sunlight. About twice the brightness of anything we have on the surface. So even though space is technically cold it is actually a big issue trying to keep the spacecraft cold. The white paint helps with this as it reflect the sunlight away from the spacecraft keeping it colder then a darker color. Adding to this white paint reflects UV lights much better which help protect plastics like Kevlar, beta cloth and insulation from getting damaged by this.
The inside of spacecrafts however is white in order to make it brighter and cleaner. It is the same reason as to why most houses use light paints inside. Things look more spacious, brighter and less gloomy when you use bright colors. It is also much easier to see things, both items which might float around but also dust and other things which could pose a danger to the astronauts.
in addition to the comments about heat, white provides a good contrast to be able to locate problems, such as leaks, damage, etc.
As stated, it reflects light. But it’s also kind of tradition, so most boosters are also white though they don’t need to reflect light because they won’t be up for long. Maybe because it looks cool standing on the pad. But they don’t need to be. SpaceX boosters are white, but they don’t bother to clean them between launches, so they’re more grey and sooty.
In addition, white is probably cheaper. Most paint colors start white, and then change as pigment is added. No pigment probably equals lower costs.
1. White reflects heat, which is useful because direct sun in space can be 250F.
2. White is highly visible which allows for greater range of visual tracking.
3. White paint has no pigment, and pigment has weight. Every kilogram sent to space costs thousands or 10s of thousands of dollars, so saving 100lb in pigment (because rockets are literally the size of buildings) could be a million of dollars per launch saved.
A black or darker than the brightest color, white, vehicle that is responsible for you staying alive and getting back safely in endless black probably isn’t the greatest design idea.
White reflects, all other colors absorb light. The absorption of light produces heat and we don’t want unnecessary heat!
Smarter sounding version:
“-external tanks that were painted white to protect them from exposure to ultraviolet rays during extended periods on the launch pad.” (quote from NASA)
The internal deco you mean? Because it looks futuristic and high tech, you wouldnt want you spacecraft control panel to be beige now would you? It’s same reason so much consumer tech is white, it’s just aestetics, there is nothing funtional about it.
Externals though, yes there it’s thermal and visibility considerations.
Because the scientists at nasa incorrectly believe that black rockets are inferior to white rockets.
Personally I think they should be painted Vanta black so when they reach space they have an automatic cloaking mode.
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