3 ms·

If reflection is such a big problem (other problems notwithstanding), there is that better-than-VantaBlack paint that presumably absorbs a lot of light. To thin

by tandr 7y ago

If reflection is such a big problem (other problems notwithstanding), there is that better-than-VantaBlack paint that presumably absorbs a lot of light. To think of it... it might cause even bigger problems with "dark object flying in a total darkness"...

jofer 7y ago
The issue with having sats be black is that black adsorbs a _lot_ of heat from the sun. Even more so with "better-than-vantablack". Cooling is actually a huge problem in space. It may be really cold, but it's extremely difficult to transfer heat without air/water/etc. You're limited to direct radiation, which is much less efficient than advection or conduction. Making things black means they'll get quite hot in the sun. That's a major problem for most satellites.
- outworlder 7y ago
  > The issue with having sats be black is that black adsorbs a _lot_ of heat from the sun. Even more so with "better-than-vantablack". It will also irradiate back a lot of heat once they are in the shade.
  - jofer 7y ago
    Yeah, but that's part of the problem as well. Thermal stresses are very real and a big problem. You want as constant a temp as possible, that that's much easier to do with a reflective exterior than a non-reflective one.
  - AWildC182 7y ago
    Imagine taking your computer and blowtorching it then sticking it in the freezer every 90 minutes for a decade. How long do you think it'll keep working?
- tandr 7y ago
  Thank you, I did not think of it - I was mostly thinking about collisions and "visual" tracking/avoidance.
dogma1138 7y ago
I’m not entirely sure that putting 30,000 “stealth” satellites into orbit is that great of an idea.
- the8472 7y ago
  VANTAs absorb well in the visible and infrared range, but not radio waves. They would also show up in IR, shedding all the heat they soaked up from the sunlight. Absorption is not the full story when you're in thermal equilibrium and also emitting the same amount of energy.

by tandr 7y ago

jofer 7y ago

The issue with having sats be black is that black adsorbs a _lot_ of heat from the sun. Even more so with "better-than-vantablack". Cooling is actually a huge problem in space. It may be really cold, but it's extremely difficult to transfer heat without air/water/etc. You're limited to direct radiation, which is much less efficient than advection or conduction. Making things black means they'll get quite hot in the sun. That's a major problem for most satellites.

outworlder 7y ago
> The issue with having sats be black is that black adsorbs a _lot_ of heat from the sun. Even more so with "better-than-vantablack". It will also irradiate back a lot of heat once they are in the shade.
- jofer 7y ago
  Yeah, but that's part of the problem as well. Thermal stresses are very real and a big problem. You want as constant a temp as possible, that that's much easier to do with a reflective exterior than a non-reflective one.
- AWildC182 7y ago
  Imagine taking your computer and blowtorching it then sticking it in the freezer every 90 minutes for a decade. How long do you think it'll keep working?
tandr 7y ago
Thank you, I did not think of it - I was mostly thinking about collisions and "visual" tracking/avoidance.

dogma1138 7y ago

I’m not entirely sure that putting 30,000 “stealth” satellites into orbit is that great of an idea.

the8472 7y ago
VANTAs absorb well in the visible and infrared range, but not radio waves. They would also show up in IR, shedding all the heat they soaked up from the sunlight. Absorption is not the full story when you're in thermal equilibrium and also emitting the same amount of energy.