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There’s a funny amount of beef around using it in art, you have Anish Kapoor who bought exclusive rights to use Vantablack artistically and man of the people Stuart Semple offering his versions Black 1.0, 2.0, 3.0, 4.0 getting ever blacker.
True, but I think that could cause issues for astronomers. Instead if seeing small points of light they could see fast moving black spots obscuring stellar objects. In a way looking like eclipses.
>Dr Noelia Noel, Senior Lecturer, PhD in Astrophysics
Is this a joke article?
As someone in this field, I don't really think this is a good idea. We already have issues maintaining proper thermals without turning the satellite into a giant light-absorbing thermal mass. Painting it black is just asking for additional thermal management budget and mass additions.
The blackbody equilibrium temperature at 1AU from the sun is about 278K. All satellite materials are fine at 278K because that's within the expected range of storage and atmospheric launch temperatures. The equilibrium temperature of a polished aluminum surface at 1AU from the sun is 416K, hot enough to melt polyethylene and at least weaken many of the relevant aerospace plastics like the PET in mylar film. Painting…
But that is NOT the temperature of something in LEO. You're ignoring everything else that adds energy to the system. Friction from collisions with atomic oxygen, down to heating up to temperatures as hot as 530 Kelvin just entirely dependent upon orientation to the sun.
Earlier quoted context omitted.
The blackbody equilibrium temperature at 1AU from the sun is about 278K. All satellite materials are fine at 278K because that's within the expected range of storage and atmospheric launch temperatures. The equilibrium temperature of a polished aluminum surface at 1AU from the sun is 416K, hot enough to melt polyethylene and at least weaken many of the relevant aerospace plastics like the PET in mylar film. Painting…
How does this happen? Why would something which reflects light on the outside get hotter than one which absorbs light? This makes no intuitive sense to me.
Remove convection/conduction as heat transfer methods, and you end up with two numbers dictating radiative balance:
Percent reflectivity in the bands it's exposed to
Percent emissivity in the bands it's emitting
The balance between these dictates temperature, and they're generally inversely correlated. Mirrors are good reflectors, but very poor emitters.
Earlier quoted context omitted.
The blackbody equilibrium temperature at 1AU from the sun is about 278K. All satellite materials are fine at 278K because that's within the expected range of storage and atmospheric launch temperatures. The equilibrium temperature of a polished aluminum surface at 1AU from the sun is 416K, hot enough to melt polyethylene and at least weaken many of the relevant aerospace plastics like the PET in mylar film. Painting…
"The blackbody equilibrium temperature at 1AU from the sun is about 278K. All satellite materials are fine at 278K because that's within the expected range of storage and atmospheric launch temperatures." But that is NOT the temperature of something in LEO. You're ignoring everything else that adds energy to the system. Friction from collisions with atomic oxygen, down to heating up to temperatures as hot as 530 Kelv…
(Though I'd rather anodize the thing black imperfectly if it helps avoid paint flecks becoming orbital debris)
True, but I think that could cause issues for astronomers. Instead if seeing small points of light they could see fast moving black spots obscuring stellar objects. In a way looking like eclipses.
I'm sure they use image stacking to mitigate these issues.
Visual isn't the only concern, either. https://observatoiredeparis.psl.eu/starlink-satellites-a-thr...
Making blank spots in the sky between the observer and the observed is something I suspect won't really be an improvement. It likely to make the problem less noticable (eg. no more b-roll of streaks in the sky to upset people) and, probably, more of a challenge to mitigate.