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How satellite ‘megaconstellations’ will photobomb astronomy images

nature.com

191–200 of 395 posts

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#192
Hopefully they can come up with some sort of 'vanta black' coating for the sats that reduces this issue. I agree with there needing to be a tax on bright, private sats in orbit. Space is getting more democratized, but not nearly so much so that an international body wouldn't be able to slap fines on companies putting 'disco balls' in orbit.

Another thing is that our skies will probably get brighter overall when we resort to stratospheric sulfide injection to try to reduce the effects of global warming. Anyone that doubts this will happen needs to come to grips with the fact that this is our cheapest most readily available means of reducing temps until we can get our emissions under control. We're going to need to fund a lot more space based telescopes to preserve our ability to do science.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#193
post #92

Earlier quoted context omitted.

The US isn't doing it. Companies are doing it. As stated in the article the company which is currently planning to place satellites at a height likely to have the greatest impact is OneWeb which is a UK company. It is soon to be controlled by the UK government and an Indian conglomerate. The satellites it launches are built by a joint venture which includes Airbus.

>>The US isn't doing it. Companies are doing it. Well, that isn't really a useful distinction in any sense of the word. The American companies are doing it, because they are allowed to do so by their country. Most countries which have any kind of space capability have their own space agencies which say what is or isn't ok to launch. If the American space agencies approve things like Starlink, then the pollution of th…

Due to ITAR regulations SpaceX and Amazon couldn't do it anywhere else either.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#194

Earlier quoted context omitted.

> SpaceX is lowering satellite launch cost by 90% for anyone, Chinese or otherwise. Are you sure SpaceX is allowed to do business with China? As I understand it NASA is forbidden by Congress from collaborating with China. Since NASA and SpaceX work together, might that limitation extent to SpaceX as well?

Spacex is subject to the same OFAC sanctions as every other US business. They are free to do business with most of China, however there are a number of exceptions usually having to do with the company participating in construction in the South China Sea. Doesn’t mean new sanctions can’t be levied and certainty China seems a likely target for future increased sanctions.

No they cannot do business with Chinese governments, ITAR forbids this.

There is already history here where a failed Chinese rocket crashed with a classified American payload and caused the whole satellite anything is now ITAR

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#195
post #145

Earlier quoted context omitted.

Light pollution is global, while a satellite streak is localised to a part of an image. These are not the same problem.

It's the other way around. It's possible to escape light pollution by moving away from electrified areas, whereas satellite streak ruins observations in every part of the world. Besides, the streaks are not really localized in the image. Its glow reportedly extends up to 15 arc seconds. That's a very large area for a carefully exposed array.

I meant light pollution affects the entire image, while a streak affects only part of it, which you can just remove.

A 30 arcsec stripe on an (apparently average) 20 arcmin detector is 2.5% of the total area, so it's not a very large area.

Overall, 20000 satellites at any given time cover 20kπ15acsec² of sky area, which is 0.0005% of total sky area, and over 1 second (assuming a satellite speed of 3.6 arcmin per second) it's 0.02424% of the sky, so roughly 1.45% of the surface area of a 1 minute exposure would have to be thrown out. This assumes that satellite streaks don't overlap, with overlap it would be less.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#196

Earlier quoted context omitted.

> SpaceX is lowering satellite launch cost by 90% for anyone, Chinese or otherwise. Are you sure SpaceX is allowed to do business with China? As I understand it NASA is forbidden by Congress from collaborating with China. Since NASA and SpaceX work together, might that limitation extent to SpaceX as well?

Spacex is subject to the same OFAC sanctions as every other US business. They are free to do business with most of China, however there are a number of exceptions usually having to do with the company participating in construction in the South China Sea. Doesn’t mean new sanctions can’t be levied and certainty China seems a likely target for future increased sanctions.

I wasn't thinking of OFAC, I was thinking of this: https://en.m.wikipedia.org/wiki/China_exclusion_policy_of_NA...

If NASA is forbidden from working with organizations affiliated with China, it seems to me that SpaceX working with China might imperil their collaboration with NASA. Then again maybe not, I don't know the answer.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#197
post #25

The article covers the mitigations already in place and how they only partially resolve the issue. These satellites are low, bright (at dawn/dusk) and very soon to be incredibly numerous. Yes, it is possible for data workflows to post-process these streaks away, but not all configurations allow this, and whereas previous intrusions were somewhat rare and could be ignored that simply won't be the case due to three com…

You won't be alone on that hill. This issue is yet another reminder that capitalism only appears to work because you assume infinite resources on a finite planet.

This one of the stupider hills to die on.

There are plenty of other factors interfering with astronomy and they can largely processed away.

>This issue is yet another reminder that capitalism only appears to work because you assume infinite resources on a finite planet.

This is complete bullshit, and a reminder that anti-capitalists are not worth arguing with.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#198
post #131

Earlier quoted context omitted.

I guess you could statistically impute that data. But it is the long tail of unlikely readings which are generally interesting, and imputation will not find those.

This is a logic flaw I see everywhere. Making a proposition for what might have been there is not a useful scientific instrument. And especially not when unseen anomalies are an integral part of pushing your field forward. If you're inferring what might have been there you're explicitly filling in based only on what you already know.

I agree, but isn't filing in what you already know a common technique when presenting things for human consumption? I'm thinking scanning microscopy, SEM, STM, etc.

The image implies that all the data is from the same instant, when it's not. Normally that's OK, but it's not always.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#199

Earlier quoted context omitted.

I personally believe that pervasive high speed internet even in remote locations will do more for humanity than the scientific cost of these satellites. However, this conversation has basically been skipped over. Maybe you're right and I'm wrong. The constellations are being launched, and there's zero chance of shutting them down once they're serving a commercial role. Considering the abundant red tape in the modern…

> I personally believe that pervasive high speed internet even in remote locations will do more for humanity than the scientific cost of these satellites. Perhaps in the US, but other countries, even poor ones, manage to do rural internet fine without cluttering the night sky. I, for one, am not stoked about the implications of an American ISP forcing worldwide coverage for themselves. Their shady business practices…

> without cluttering the night sky

Current mitigations (visorsat) by SpaceX already make the satellites completely invisible to the naked eye. It’s less of a visual impact (zero once deployed) than any other visible LEO satellite or air travel. Celltowers high enough to need a light are highly visible and are a much greater visual impact than Starlink.

Re: How satellite ‘megaconstellations’ will photobomb astronomy images

#200
> “There’s no place to hide in the middle of the night from such a satellite constellation,” says Tony Tyson, a physicist at the University of California, Davis.

Fortunately this has never been true for Starlink, which are at such low orbits they are always in the earths shadow at night, excepting dusk and dawn.

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