Astronomers don't look first and then aim their cameras, and most interesting features (essentially all of them) require long exposures, which would make this problem a slight, one-time variance in brightness.
Visual isn't the only concern, either. https://observatoiredeparis.psl.eu/starlink-satellites-a-thr...
I'm not sure making space debris invisible to visible light is a good thing, either.
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 polished aluminum black drastically raises emissivity along with the lowered reflectivity, and brings its behavior closer to a blackbody.
So does allowing aluminum to oxidize, which it does almost instantaneously in atmosphere. So it's not like it's going to change anything drastically.
The reason this seems like it should change things a lot is that you're used to convectively cooled matte surfaces on Earth, where emissivity and radiative cooling is a less relevant factor and the only significant effect of painting something black is primarily that it absorbs more energy.
>Dr Noelia Noel, Senior Lecturer, PhD in Astrophysics
Is this a joke article?
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.
Can I get some of that for my target gun sights?
The proximity sensor is the trigger. Things work fine with the phone in my shirt pocket with the sensor poking out, but my phone keeps falling out when I have to get gymnastic while trimming things. So I've been wondering if I put a little patch of ultra-black over the proximity sensor would it absorb enough light to solve my problem.
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.
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.
(Though I'd rather anodize the thing black imperfectly if it helps avoid paint flecks becoming orbital debris)
goda90•1h ago
_joel•1h ago