> I'm not trying to really frame it as SpaceX. I think it's a bit more fundamental than that. There are benefits to lots of satellites providing services, there are benefits to decreased launch costs. SpaceX is only really in the discussion because they've leveraged the latter to achieve the former for their own benefit (and hopefully the benefit of others).

you're right that this isn't just spaceX, this is a much larger problem. Not of satellites in general, mind you, we've been successfully contending with those for many decades now (they do have a detrimental effect from an astronomical perspective, but we can deal with them for the most part or incorporate them when designing instruments/experiments). The difference is the brightness and number of satellites in a constellation like starlink. They are brighter than >99% of other satellites.

> Put another way, even if Starlink wasn't a thing, do we think there wouldn't be the same amount of more satellites in the sky for other reasons and for a hundred different companies 20 years from now? If this is an inevitable problem (and I think it is, unless we decide Space industry is just not worth it), then what's the solution for astronomy?

The solution is more oversight, disclosure, and planning. Space-X is obviously going to do everything to the letter of the law and no further, because they are a competitive business. What you do in circumstances like that is add regulation and oversight so everyone is subject to the same rules and standards.

https://www.lsst.org/content/lsst-statement-regarding-increa...

^ the above shows the results from some collaboration that, if Starlink follows through, could mitigate some of the effects in LSST (not completely). But this is the sort of thing that needs to be done before companies like Space-X start launching things.

> They announced publicly and filed with the FCC 4-5 years ago. The first criticism I'm seeing about telescopes or astronomy is in late 2018 and 2019, and is more worried that they won't be able to avoid collisions and we'll have kessler syndrome[2], but maybe you know of earlier criticism. Was there criticism from the astronomy community prior to this? It seems like if they thought it would be a problem, they should have spoken up. If they didn't, why didn't they? The number of satellites is increasing, has this been an entirely non-issue for that community?

Actually, yea the collisions are a problem for a variety of reasons, but I'm not even talking about that, I just mean the problems arising from the combination of very bright and very numerous constellation satellites. But that is another good point, and another good argument for international regulation to prevent catastrophes like that.

Back to your point: Space-X actually didn't release any relevant technical info that astronomers could use, so the brightness was quite a nauseating shock. Space-X was actually surprised by the brightness themselves (which is astounding to me). Here's a quote

"However, even at fifth magnitude the satellites are bright enough to pose a problem for professional astronomers who require long exposures on large telescopes to observe faint celestial objects. Seitzer said that, before Starlink, only about 200 objects in Earth orbit were that bright, but by the end of 2020 that could increase by a factor of nine because of Starlink. “So, life is going to get really interesting,” he said."

...

"While astronomers may have been aware that SpaceX was planning to launch Starlink satellites, they didn’t expect them to be that bright. “What caught everyone, principally, by surprise was the sheer brightness of the ‘string of pearls’ going across the sky,” said Jeff Hall, director of the Lowell Observatory in Arizona and chair of an AAS committee that handles light pollution and space debris issues." -- [https://spacenews.com/starlink-vs-the-astronomers/](https://...

The point is that the current legal frameworks in place are from a different era and are not prepared to deal with Starlink-like constellations, so astronomers don't really have much they can do at this point (there's a suit against the FCC right now, but who knows if or when that will succeed). There needs to be a collaborative solution and better oversight because completely destroying billions of dollars of R&D may sound like draining the swamp but all you are really doing is needlessly destroying billions of dollars in R&D. There's no reason why there can't be an oversight committee that enforces certain limits on constellation manufacturers (e.g. albedo limits, etc).

From https://docushare.lsstcorp.org/docushare/dsweb/Get/Document-...:

"There is a long history of international regulations for radio interference via the International
Telecommunications Union (ITU) going back to the 1930s. However, there are no regulations in place for light pollution from space as there are for the radio spectrum....While
the willingness of SpaceX to help is a sign of hope, without federal and international requirements for space light pollution, it is far from guaranteed that others would follow suit."

> Whatever it is, we should just do it now, and maybe try to get some more money out of SpaceX for it, because it needs to be done anyway. This is a "the world is changing because of technology, I wish it wouldn't" type of problem, and we've seen how those play out. You're much better off if you work with the flow than against it. That is, coal miners can complain all they want and try to get intervention, but those that see the writing on the wall and jump into those retraining programs sooner than later will be much better off. That doesn't mean they shouldn't petition the government for more subsidies to help with that though...

There fundamentally no real solution, only partial mitigations, and those are only possible with cooperation. Things like transient detections (useful for broad swaths of astronomy like cosmology, but also for near-earth object detection (i.e. asteroids) that has some very important practical benefits) will suffer greatly. Astronomers are simply asking to "work with the flow" -- we're doing absolutely everything we can to do that.

Astronomers are trying to get the word out now that this is a huge problem that needs a solution, otherwise we will lose an insane amount of pricey (and priceless) research. Right now astronomical organizations are playing extremely nicely with Space-X, not because we like them (I think a lot of people are rightly furious, some of these issues were due to pure incompetence and recklessness on Space-X's part), but because we have no other good option available to us. Luckily in this case, Space-X is relatively cooperative and supposedly "on track" to make some changes to partially mitigate some of these issues, but fundamentally some instruments are just SOL. And it will get much, much worse without interventions by governments.

This is very different than a "coal-miners" situation — we have no alternative. We either do the research, or we don't. Not to mention, there are currently billions of dollars of research being affected right now. That's already been payed for by you, the taxpayer.

> Okay, but why? I can accept this is the case, and even likely for some things (I suspected not everything could be done exactly the same in space), but without details how am I or anyone else to weigh whether they think that specific task is more or less important than the alternative?

Well, multiple things: ground based observatories have the ability to upgrade/maintain instrumentation (very very important), more sensitive/larger apertures that aren't really possible to put into space (these make it possible to do, e.g. LSST), extreme environmental conditions in space mean the addition of expensive complex engineering challenges, etc. Some things are possible to do from space, but mean 10-100x multiplier on the cost and/or development time of an already expensive project, regardless of delivery costs. Some things, like 8.3 meter mirrors that involve large machines to carefully assemble in place are just never going to be feasible to do in space.

> In that case, maybe what we need are some legal frameworks to make sure this is assessed ahead of time (not that we can enforce anything the space agencies or companies in other countries).

yea thats exactly what we need!