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Study: ultra-black coating could reduce satellite light pollution

surrey.ac.uk

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Re: Study: ultra-black coating could reduce satellite light pollution

#41

Post by iririririr »

Plankaluel wrote: post #35
rose-knuckle17 wrote: post #30

Sounds like what my eye doc says when he busts the laser out for medical work on my eye. His work creates blank spots in my FOV. Not noticeable at all walking around, but they make detail vision difficult. Everything from artistic project work to seeing the center dot on screen in a shooter, and it makes refractory vision checks to figure out my Rx near impossible. The letters in the eyechart just disappear unless ca…

I don't think this is comparable. One is generally taking long-time exposures for astronomy pictures (hence the streaks). So if the satellite is simply blocking light, in the worst case, it will block the light of a star, maybe for a few milliseconds(?) dimming the star in the final picture by a minuscule amount. This might still be problematic (influencing spectroscopy? dimming the star slightly, influencing some me…

astronomy today point to a small piece in the sky to measure some binary star that is barely one pixel on the sensor. now you covered it with a black satellite right when then unique event was about to happen... did it not happen or was hidden by a new satellite?

also, black coating is old news. very old news. and musk said he didn't consider for starlink because he doesn't have to pay for something that doesn't make money directly for himself. so this whole discussion is pointless.

Re: Study: ultra-black coating could reduce satellite light pollution

#42

Post by DoctorOetker »

infogulch wrote: post #19

The entire underside of these satellites is a big phased array antenna. Maybe you can paint it so it absorbs all the other wavelengths, but it would be counterproductive to absorb the radio wavelengths used by the antenna itself since ground emitters would have to increase the gain to get through it.

communication link bandwidths are typically miniscule compared to optical spectrum of the sun

Re: Study: ultra-black coating could reduce satellite light pollution

#43

Post by DoctorOetker »

thecompilr wrote: post #28

I know many cruise missiles use star navigation, I wonder if satellites have any effect on that, and if they do that might be the catalyst to reduce that pollution.

there are a lot of stars, the probability of obscuring a sufficient number of suitable stars is astronomically small

Re: Study: ultra-black coating could reduce satellite light pollution

#44

Post by _joel »

ceejayoz wrote: post #29
_joel wrote: post #22

Earlier quoted context omitted.

I'm sure they use image stacking to mitigate these issues.

They do, but they're also very openly frustrated already with the proliferation of large satellite constellations. Visual isn't the only concern, either. https://observatoiredeparis.psl.eu/starlink-satellites-a-thr...

They (SpaceX) added Geofencing to the arrays so that they switch off when over radio telescopes. How well that's working now (I notice that article is a couple of years old) is up for debate.

Re: Study: ultra-black coating could reduce satellite light pollution

#45

Post by cyberax »

rbanffy wrote: post #38

I noticed the word “heat” is not mentioned anywhere in the article. Considering this reflects 2% of the incident light and absorbs 98% of the sunlight, I would expect the cubesat to get very hot very quickly. It’s been a while since I last engineered something where thermals were a consideration, but this just doesn’t feel right.

I think it only needs to be on the Earth side of the satellite?

Re: Study: ultra-black coating could reduce satellite light pollution

#46

Post by kazinator »

Gravityloss wrote: post #11
mikeodds wrote: post #5

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.

I saw a few of these black Anish Kapoor sculptures. The experience was worth the cost. The brain has a hard time processing it.

Well, you've not actually seen the sculptures per se, only a missing area of the visual background, shaped like outline of the sculptures.

Re: Study: ultra-black coating could reduce satellite light pollution

#47

Post by gmuslera »

One problem with trying to make satellites invisible is that you are making them invisible. Probably the dynamics up there are not the same as down here, or try to apply logic that doesn't work in that environment, but with secret, or failing, broken into pieces, with fried electronics or whatever satellites you may be losing an important hint that something is there.

Re: Study: ultra-black coating could reduce satellite light pollution

#48

Post by binarymax »

mhb wrote: post #26

The Darkest Clothing in the World: https://youtu.be/N9VaJKIO1JA?si=UI36apNYUe5mlxWd

Thats really cool. He did a fine job sewing. I tried something similar with green-screen fabric and followed the same procedure: make a pattern from existing clothing, cut out the material, and sew it up. It's very hard.

Re: Study: ultra-black coating could reduce satellite light pollution

#49

Post by jacknews »

mikeodds wrote: post #5

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.

Semple's humorous long-form performance art, pillorying Kapoor, while developing a menagerie of new pigments, is much more interesting than Kapoor's sculptures.

Anyone could have made at least the same with the given material, and a more talented artist could stun, but sadly they are not allowed to because contract.

Re: Study: ultra-black coating could reduce satellite light pollution

#50

Post by schiffern »

rbanffy wrote: post #38

I noticed the word “heat” is not mentioned anywhere in the article. Considering this reflects 2% of the incident light and absorbs 98% of the sunlight, I would expect the cubesat to get very hot very quickly. It’s been a while since I last engineered something where thermals were a consideration, but this just doesn’t feel right.

Correct. This is why SpaceX rejected using black coatings alone for Starlink. Mirrored surfaces that they tested instead were darker than VANTA black.[0]

On some surfaces they use a SpaceX-designed coating called Low Reflectivity Black, which is the least specular space-rated paint by a factor of 5.[1]

[0] https://www.youtube.com/watch?v=MNc5yCYth5E#t=2430s

[1] https://starlink.com/public-files/BrightnessMitigationBestPr...

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