How satellite ‘megaconstellations’ will photobomb astronomy images
nature.com
nature.com
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 companies from one country.
This is cost turned into an "externality" and foisted upon astronomers--at every scale of investment--all over the world. Stock holders in these companies won't pay for it, but tax payers everywhere will pay for the mitigations. Not cool. This is a hill I'll die on.
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 world, it does seem like it was a little thin on the ground here.
I've had faster Internet than the average Starlink speedtest says, in rural Romania, at the foot of a mountain, wild bears and all: https://twitter.com/q3k/status/1172621386977861632 . Internet access in rural areas is pretty much a solved problem, it just now hinges on enough of a societal push to apply this solution where needed.
Starlink is yet another SV-style attempt to solve (US) societal problems by blindly applying technology. Except this time, this also affects other countries, and we're furious.
The point of my comment isn't to defend the satellite launches, quite the opposite.
It's saying that even as somebody that would be in favor, not carefully considering the trade offs before giving permission to permanently alter the night sky is not acceptable. This is exactly the kind of thing that bureaucracy should make painfully slow.
When was the last time that you were in Africa? And in which country, because it's an entire continent.
EDIT: So I guess HN doesn't like being called out on https://africasacountry.com/ issues? Well sorry not sorry, but as someone born in Ghana I'm more a little tired of the sentiment on display in the cited part of comment I'm reacting to, which is the implication that Africa as an entire continent is inherently and forever will be a place too poor to have proper infrastructure.
Perhaps you are. I'm from the same country, and I couldn't be happier :).
I mean, LEO Internet constellations are awesome for providing access (not just in rural areas, but also in remote areas and at sea). But more than that, we're talking Starlink here in particular. The problem it's solving isn't (just) how to improve Internet access for some people. The main problem it's solving is how to fund SpaceX's R&D on Starship. Which translates to dropping another order of magnitude from the cost of access to orbit. Which will, longer-term, translate to a boon for astronomy.
The North Slope Borough in Alaska is nearly the size of Romania, but has only about 9,000 people living there. The state as a whole is larger than all of Western Europe, but has only about 700,000 people.
Much of Canada is the same, only more so.
If we are just going to completely ignore costs, then I can say that getting great astronomical observations is solved as well, since we can just launch satellites to take the observations instead of doing ground-based observations. So it's not clear what the big deal about these satellites is anyway.
No it isn't. Just because it works for you it doesn't mean the same solutions can apply everywhere.
But I know people from rich countries like UK, US, Germany with download speeds under 5 mbps paying more than you would pay for the most expensive line on Romania.
I've gotten decent internet speeds in one place that looked pretty wild, therefore worldwide internet access is a solved problem.
So it's not exactly a good potential userbase for starlink. However, most of South America, Africa and Central Asia could benefit massively from Starlink and start participating in the global digital economy
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 and the questionable reliability of the US government make it very hard for me to see many upsides.
Were this to be released only in remote areas and third-world countries, I would agree that there is a large net benefit to Starlink. However, because of the way the system is designed, every country on the planet will now be forced to deal with a solution for the anti-competitive behaviour of the American ISP market.
As long as Starlink is managed by a an American company, I have little faith in their intends and purposes. Being able to intercept or duplicate random internet communications worldwide seems like an NSA wet dream come true to me.
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.
Most of sub-saharan Africa has slow and expensive internet. I would guess there is 1 billion people who will have access to the internet via mobile tower with starlink & competitors backhaul in a few years. This is enormous.
There's nothing in the landscape that prevents Africa from running fiber to every house like Eastern Europe has been proven to be capable of. In fact, a lot of infrastructure is already there. Geopolitical instability, poverty and instability of the power grid makes it very unattractive to build data centers in the continent and that's what's forcing ISPs to use expensive cables to access most websites, driving up the cost and reducing the speed.
This problem can be partially mitigated by using StarLink instead of oceanic cables, but I don't imagine their system will be able to replace the fiber optics that carry most large volumes of data between governments. StarLink is fast, but still depends on ground stations for decent speed internet access. Collecting internet traffic for one entire continent on another isn't feasible in the plans I've seen.
StarLink will reduce latency and improve coverage for customers already using satellite internet connections. African people can already use those if they have the means to afford it, yet many African cities have dial-up or slower internet access because of the lack of resources.
The obejective is noble but can you provide any realistic data or estimates of how this infrastructure can scale to more than a few million users and _still_ be high bandwith. Beyond that your bandwith will go down as you add more users.
The only use-cases that this serves are high-income people that want to go off-grid but are unwilling to sacrifice high-bandwith, and military deployments (which SpaceX does not hide as an objective).
Actual rich people can afford to put in fiber or line of site wherever they are. $100,000 or whatever, doesn’t matter. This is for the regular people in rural areas.
Seriously, has no one making these claims ever talked to someone whose best internet is geosynchronous satellite? Do they think only the very rich live in rural areas?
Rural internet access is absolutely not an US-centric issue, many parts of the world have much worse infrastructure. Being opposed to new technologies because "I already have fast internet" is unbelievably narrow minded.
2) The only limitation on bandwidth (and thus users) is the number of satellites in orbit. If the constellation bandwidth is saturated, launch more satellites and you get more bandwidth.
3) I guess you'll just ignore the use cases for the tens of millions of non-rich people who literally can't get decent internet because it doesn't exist where they live?
One nation launching thousands of satellites because three companies want to make a pile of money and also because that one country can't get it's act together and do something about its own predatory cable companies seems like a weak argument to make from a moral point of view.
But what about third world countries and such? Summary opinion: The people who could afford Starlink already have broadband, and we wouldn't want to subsidize others access, would we? That path leads to socialism and the USPS. Or indeed broadband as a right attached to cable company's license. Impossible! (In that one country.)
Let third world countries sort out their own broadband and make their own money. And let them have their own view of the damn stars.
If the internet was simply a wellspring from which one could obtain knowledge you may be correct.
But most likely, the internet will instead be used to proliferate bigoted and intolerant opinions, while spreading lies and misinformation in the form of crude memes. As the last of human populations without high speed internet comes online, they will expand their capacity to inflict harm at speeds never before seen.
Weep for the clear skies we have lost. Forever.
Using keps and scrubbing exposures in post is something we could already do decades ago. It’ll just be a new part of the workflow and eventually the space NIMBYs will quiet down.
Let’s not pretend this was the one true way to get around Comcast et al’s stranglehold though. That problem could have been solved politically with regulation plus (in the countryside) ground based radio, or (in cities) with regulation of cable infrastructure such that it was separated from packet-routing and customer-service.
If satellite ISPs genuinely are the solution to entrenched telcos then every streak of light in the sky is a testament to the failure to find a solution. We will look back and wish we had been able to achieve a system of sensible business regulation delivered by those elected to do so.
I agree. However it's going to be a tough nut to crack because that belief is self-reinforcing. People who believe the government can't do anything right also seem to advocate policies that make the government more ineffective, which provides false confirmation of the initial belief.
The response to COVID-19 has been an expectancy on equal access to Internet and either the telco gets to capitalize on their geographic monopoly or the rural folks get short changed with 1980s dial-up or GEO satellite link.
Ground-based radio requires line-of-sight to somewhere with both power and an uplink. Nevermind "third-world" countries - the vast majority of the United States, by square foot, does not have this. Rural wireless is incredibly dependent upon topography, many places will just never get it.
I live one hour from SF. I have rural wireless broadband (bounced off a solar relay I installed on a hill). It's terrible, but I'm still one of the lucky ones - most of the properties we looked at when shopping did not have this access, and the only internet option was Hughes.
The valley is 400’ deep and has 50 copper pairs coming up the side, of which 20 come to the road the house is on, and 10 remain by the time you get to the family property. 3 more are taken by properties down the way, so 7 pairs (or ~50Mbps) lay unused. It would be interesting if the copper was changed to a 100% utilization rate.
The point though is there is power and copper telephone at the site. And a road! At some point, someone managed to invest in infrastructure for this house. In some sense it’s quite disheartening that the only modern equivalent to that kind of infrastructure investment is the spaceship endrun around the incumbents.
My hope is that these constellations put pressure on the ground based incumbents to fix their shit. The result might be that we get cheap enough internet on the ground that the constellations become unprofitable and shut down. Might be a win-win without politics and regulation.
No.
-- Rural Resident
So you're straight up saying that because the regulation of US telco companies is ineffective and/or corrupt, the entire planet should pay for it? That's your argument? Please tell me that's not your argument.
As a reminder, astronomy is not as much about the 'image' as it is about the 'measurement'. Editing pictures like in Insta is not the point here, you can't fill things in.
Remember, astronomy images generally have long exposure times, which already involve tracking the sky, and then averaging out values in the exposure across minutes/hours/days/whatever.
A satellite passing over a point in the sky means that area of sky is affected for only a tiny fraction of the total exposure. As long as you have a database of all satellite locations, you just don't include data from those time slices in the final average. Or if you don't know where satellites are in advance, you just do basic outlier detection -- the kind that already eliminates things like airplanes, birds, the ISS, etc.
Nobody's filling in anything with "black", and the area of satellite interference can be easily expanded to include the "glow" area.
In the end, the quality of the overall image is degraded by a tiny fraction of a percentage, which can be trivially overcome by extending the total exposure time by the same tiny fraction of a percentage.
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.
Taking multiple exposures isn't always possible, this may be a continuous multi-hour exposure. Additionally if you're looking for transients, NEOs, or star field mapping then there is definitely lost data that can't just be inferred.
The conversation isn't just about halting launches. It's about recognizing and working to mitigate the issue now before we get too far down this path.... and accepting that it's not a trivial "photoshop" problem.
I'm frankly amazed at the arrogance on display here. Do you honestly think you know better then the entire field of astronomy?
Think for instance about CO2 levels. Is it such a big deal if they reach 1% of the atmosphere? It's only a small part after all.
(1) astronomers are pretty darn aware of everything going on, and it's really shocking as an astronomer to see these sorts of claims. There have been close collaborations with Space X to try to mitigate some issues, but these are partial mitigations and the most important ones are only planned, not implemented. The "successful" mitigations I think you're referring to is their "DarkSat" coating, which is not actually a successful mitigation. It is still ~2x as bright as the ~maximum level of acceptable brightness for e.g. LSST.
(2) Space-X did not release any details about brightness characteristics, and they themselves claim that they were "surprised" by the brightness. To people that work in space rather routinely, that is staggeringly incompetent.
(3) > why do most not know Starlink was never visible except at dawn or dusk
Near earth object (NEO) detection only happens during these times. NEO includes "asteroids that threaten human life" so I would hope you agree that this is pretty important. Also, depending on latitude and time of year, "dawn or dusk" can constitute your entire observing window. So this doesn't really make things better.
(4) all of these mitigations should be done before companies can start doing ~10,000 satellite launches. The only reason this isn't done is outdated legislation that never conceived of this being possible.
What is a loss of some percentage of astronomical observations today, if it means putting a telescope on the backside of the Moon in 20 years, or a ridiculously large "virtual telescope" via a satellite constellation doing interferometry?
I already have to do this for aircraft, and aircraft do a LOT more photobombing than satellites.
The satellite trail images people post all over the internet to fear monger the public are actually processed exactly the OPPOSITE way that astrophotographers would process an image stack. They are processed by taking the max at each pixel stack to emphasizing the outliers in the stack instead of eliminating the outliers and averaging the rest. No astronomer would ever do that.
I can imagine they might be a bigger threat to radio astronomy, though.
It's silly to die on a hill that's inevitable, it's much wiser to stand on the hill and reach higher. The future of space exploration is in space, not on the ground, and the proliferation of these satellites is a sign that space exploration is getting cheaper.
Just like people were shocked that there was only one or two computers in the world at one point, they will be shocked that we only had Hubble for so long.
> So in April, SpaceX instead began launching Starlinks with a sunshade to block sunlight that would otherwise reflect off its antennas, which are the main source of the Starlinks’ brightness once they have reached their final positions.
> So far, only one of these ‘VisorSat’ Starlinks has finished the journey to its final orbit of 550 kilometres above Earth. Amateur astronomers have reported that the sunshade appears to make the Starlink fainter than it would otherwise be.
> But astronomers are still awaiting further confirmation that the modifications have a significant effect, says Meredith Rawls, an astronomer at the University of Washington in Seattle. Regardless, SpaceX is now launching all of its Starlinks with the sun-shielding visor.
It seems that the impact of the sunshade mitigation is not yet fully measured?
With plentiful availability of orbital delivery, we can also expect more earth-orbiting space telescopes in our future, including private ones and with numbers possibly several orders of magnitude higher than what we have today. These will have higher orbits so that will help, and they will be largely immune to atmospheric effects.
I would suggest the astronomy community ask SpaceX and others to commit to giving key projects free or low cost launch services or ride sharing to orbit, to help compensate for some of the costs you allude to. If asked directly, Elon is often responsive.
Yeah, but the responses can be unpredictable :)
It would be great if this billionaires would also launch scientific satellites payed from their pocket to compensate, then I would change my mind.
This should start a golden age of space astronomy, even if Elon doesn't give away some telescope launches as PR.
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?
You destroy my house and I should be happy you offer me a discount when I buy new blueprints from you.
They don't owe you anything.
I also do remember the story how NASA got a couple decommissioned telescopes from some intelligence agency, which turned out to be an order of magnitude better than Hubble is, and the agency was getting rid of them because they were already outdated. I do remember reading that if those were put into astronomy use they would be a lot better than anything we have currently, but of course those are being used for taking pictures of military sites and tanks, rather than stars.
Someone had a great idea, we tax all bright objects put in orbit, then there is an intensive to make the satellites less bright and we make the people that pollute pay and not the public.
Space telescopes offer advantages for particular types of observations, but there are many types of observations for which ground-based telescopes are superior. The basic advantages that ground-based telescopes have are:
* Larger collecting area, which means more photons collected, which means you can see fainter objects.
* With adaptive optics, ground-based telescopes can actually achieve better resolution than space telescopes over small fields of view.
* Ground-based telescopes are far easier to maintain and upgrade.
* Much looser weight, size, radiation-hardening requirements mean that you can do things on the ground that would just be unthinkable in space. You can attach things like massive spectrometers to ground-based telescopes, without having to worry nearly as much about form factor and weight, or whether radiation will damage your electronics.
The advantages that space telescopes have are:
* No weather to deal with.
* You can observe UV and IR wavelengths which the Earth's atmosphere absorbs or emits in - which is extremely difficult/impossible from the ground.
* You can get high resolution over large fields of view. However, you can't reach the same resolution on small fields of view, because ground-based telescopes with a large aperture + adaptive optics will beat you there.
Basically, at any fixed budget, you will be able to build a much larger, more complex instrument on the ground. You only go to space when there's a compelling technical reason to do so (e.g., you need to observe UV light).
Optical aperture synthesis with electronically connected telescopes https://www.nature.com/articles/ncomms7852
And even with free launches space telescopes are still extremely expensive, since the telescope and all it's instruments has to work in space without any tweaking or possibility for upgrades. Ground based telescopes are used for decades and upgraded with newer instruments over time.
Optical aperture synthesis with electronically connected telescopes https://www.nature.com/articles/ncomms7852
Interferometry gives you high resolution at the cost of sensitivity. And there way more things that require high sensitivity than high resolution. And I haven't even mentioned spectroscopy, which is hugely important in modern astronomy. And there is no way around having a big light bucket - I wish there was.
"Won't somebody please think of the astronomers!" is a moral panic that I just can't get behind.
Astronomy is great. But world-spanning wireless internet is great too. If 5% of astronomical observations get messed up because 100% of people can now have access to the internet, then that is just a big shrug from me.
Not to mention there will be far fewer non-processed photos. Most people won't care, but it just seems like nothing we see anymore is real.
I am now imagining a science fiction story where visitors to Earth initiate communication with us using faint arcs of light across the night sky. No one notices and the telescopes and cameras filter them all out. The visitors go home, sulking.
To me it seems completely impossible. How exactly do you expect to replace the missing information? Statistically from the neighboring pixels or frames? That works if your goal is to make an image prettier, but if you want to make measurements on the data "inventing" the background is not good enough.
Yes, the sats will occlude things anyway, and their brightness is a big problem, but they are fast moving, they can be mitigated by moving to may short expo images combined. Yes, it's an undue burden, SpaceX should do more, but they can't solve it completely.
In LEO the apparent movement of satellites is around 3.6 arcmin per second, which means for an average sized detector that covers maybe 20 arcmin it takes about 6s to produce a streak that covers the full length of the detector (bit longer depending on the angle). If you want it to cover less than 50% of the length of the detector you have to limit your exposure time to under 3s, which means your duty cycle will be between 60% (if you have a fast camera) and 10%(!).
And that's without even considering the loss of sensitivity you incur, because each image will have lower signal to noise since even with those long readout time the readout noise is still significant.
Second of all: I highly doubt that this is "trivial", given that observatories are built in the most remote areas of the planet because light pollution was already an enormous problem before these satellites appeared, despite the extra costs that adds to any such project.
bit dramatic for a comment on the Internet
This issue is yet another reminder that capitalism only appears to work because you assume infinite resources on a finite planet.
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.
It’s only real Achilles heel is tragedy of the commons (like this), which is a problem for the isms as well.
Space is a shared resource. One use shouldn't infringe on another.
That is a very naive viewpoint.
Sure, if you're an astronomer this is annoying, and will cost you some effort and money and time. But you'll still be able to do astronomy. Meanwhile, if you're not an astronomer, the satellites will not be visible to the naked eye in their final orbits. The entire surface of the Earth will gain low latency broadband internet access for the first time, and new launch systems will drastically reduce the cost of access to space, enabling more space-based astronomy.
This externality needs to be captured for it to be fair.
I'd argue that the positive externalities of the latter far outweigh the negative externalities of the former when deciding how to tax spacex.
They would not. It belongs to the whole of the population, not any part of it. Depriving any part of the population, especially without consent, is what's unfair and requires compensation.
> I'd argue that the positive externalities of the latter far outweigh the negative externalities of the former when deciding how to tax spacex.
This sounds like a great way to introduce abitraryness into the situation. If it has a value to all these parties then it has a price and if people are going to deprive other people of that then they can pay for those people's loss, and even better, get everyone's consent instead of making assumptions about the greater good and collective good.
If they're all going to be this reflective, satellites will be the main thing we see in the night sky a few years from now. Forget about astronomy; 10 years from now you'd be telling your kids "when I was your age we used to be able to see constellations of stars in the sky". By eye, only about ~5000 stars are visible in the night sky.
Prime astronomy hours are when Starlink is in the earths shadow.
See for example this guy who tried to model this for the lower number of 12000: https://twitter.com/Alex_Parker/status/1132335640605945856
"However, at low elevations near twilight at intermediate latitudes (45°–55°, e.g., much of Europe) hundreds of satellites may be visible at once to naked-eye observers at dark sites."
This is referring to Starlink's 12000 satellite constellation, so thousands absolutely is the order of magnitude we're talking about when (if) they go to the planned 30000 and when other companies do the same.
[0] https://iopscience.iop.org/article/10.3847/2041-8213/ab8016
And new Starlink have visits limiting their reflectivity even during dusk and dawn.
I hope this really does work; as far as I could tell no such satellite has yet reached its final orbit.
It boggles the mind that this seems to be an afterthought to something this potentially consequential.
Isnt Elon helping to advance human knowledge as well?
Starlink satellites are only visible at dusk and dawn, they are in the earths shadow during prime viewing hours.
And SoaceX has already added visors to make new Starlink satellites nearly invisible.
In what wavelengths?
I also recall last year looking up and seeing a string of about 20 bright lights moving quickly across the sky and wondering if it was the start of WW3. Turns out it was a SpaceX launch.
Like pollution, I think this is another perfect example of a negative externality. A few companies stand to benefit quite a lot by incurring costs and risks onto others. Maybe these its possible for astronomy and other endeavours to work around this but it doesn't seem fair that they should have to be the ones to pay for it. If it isn't possible to work around then I think we have a bigger problem here.
Personally, I'd like to see these orbits like realestate which are commomly owned and democratically managed by all of humanity. Then companies could, if people are willing, temporarily rent them with proceeds equally distributed. Like in pollution, I don't think market demand for wireless Internet really suffices as a vote here and we need to make it more explicit to really gather consent.
Wouldn't it be neat if the net result is that capturing the negative externality actually funded the launching of better space based telescopes?
The telescopes from space can't do what the Earth based can, so the premise is false.
I thought Hubble, JWST etc could do basically everything a ground based one could do only better? Excluding radio telescopes which are huge but not effected by satellites anyway.
Absolutely.
> What are they missing?
Everything. Whatever one can do on Earth which requires big optics and maintenance is many millions times more expensive to do in the orbit. And the many million times higher expenses of all astronomical projects in the world are certainly not going to be covered by the operators of the "cheap and small" satellites.
Optics, for the purposes we talk about, just doesn't work small. One needs big telescopes, big telescopes just can't be simply launched like the "cheap and small" can -- there are no scalable technologies for that.
Imagine it like this: there is a technology to launch "ant" satellites. But on Earth, one has "elephant" observatories everywhere. No rocket can even launch a single one. And the maintenance of an elephant in the orbit is insanely complicated.
So those who dismiss the problem with "ha ha we can send ants for them too" just show that they don't even understand what the problem is. But to uninformed people, it sounds "plausible."
No, not everything we've discovered was made by Hubble, and also won't be made with JWST.
And the demonstrated complexity of JWST should just give you pause, if you read about it. It's still not launched. The direct development of it started in 1996, the current plan is to launch it "just" 25 years later(!) You know all the problems to "get it right" to unfold? Exactly because the limitations of what can be launched and how.
More specifically, at one moment in time it was believed that the atmosphere limits what can be done from Earth. But then these problems were solved: for almost all purposes, Earth based observatories remain millions of time cheaper and better ways to make observations (as in, when something gets expensive enough, it won't even be done at all).
From 2019:
"This Is Why We Can't Just Do All Of Our Astronomy From Space" by Ethan Siegel
https://www.forbes.com/sites/startswithabang/2019/11/27/this...
Moreover, you can also read in other articles that even the approaches that were suggested by the astronomers to mitigate the problems were completely ignored by the satellite operators.
https://www.forbes.com/sites/startswithabang/2019/11/20/this...
https://www.forbes.com/sites/startswithabang/2020/01/30/dang...
Putting it into a 9 meter diameter Starship, possibly in multiple pieces that would be assembled and periodically serviced by crew flights would make it all much easier, cheaper and more performant.
space is the last realm of mystery. to me, a glance toward the sky and the stars has always been the fastest way to feel the presence of God. it won't lose that for me, even if the daytime sky fills up with blinkenlights. but it might not provide that for anyone else, anymore, if it stays—forgive me—on this trajectory.
> The planets are all long gone. The inkblot finally closes overhead and the last star winks out. The gibbous Moon remains shining balefully down on the world for a tense and hopeful minute, but then, in an eyeblink, is swallowed up by one final event horizon, and spirited away.
> Left in utter darkness, the former astronomer tries and fails to deal rationally with his loss, and his isolation from the human race who, as the voice rightly tried to tell him, has really lost nothing.
This is not a real thing that will happen.
The whole astronomy problem could be solved if FCC had teeth and forced us to get the fiber connections we already paid for
If the FCC had teeth the US would have internet going up to the "edge" of nowhere (for some definitions of the boundary), but there are always limits. Satellites nicely complement that by working best in non-dense areas.
From "Survey of cost models for space telescopes"
Now the Falcon Heavy can lift over double the payload mass of the Space Shuttle to orbit, for less than 1/40th the cost per pound.
On the ground, $1 billion or less buys you an extraordinarily large telescope such as a 40 metre mirror or a distributed array. These are needed to study very distant objects in detail and impossible to build in space.
And space telescopes don’t suffer from atmospheric distortion, can focus on the same spots for days straight to collect more light, etc. those are huge advantages.
And _yet_, despite launch cost supposedly being suuuuper large, weight played no clear role in total cost. Not sure how that is a counter argument?
On top of that SpaceX has also not proven to be real friendly towards space telescopes, so that just "moves" the problem. See for example: https://www.forbes.com/sites/jonathanocallaghan/2019/09/02/s...
It seems unfair to paint SpaceX as anti-space telescope on that basis.
I'm not saying they are anti-space telescope. I'm saying I'm seeing little evidence they want to play nice with other people who have a stake in space. I have seen mostly evidence to the contrary.
Regarding that particular incident; ESA's (way larger) satellite had that orbit / trajectory for quite a while before SpaceX decided to enter it's path. SpaceX should never have created that situation to begin with. And when the situation was created (for whatever reason) SpaceX should have manoeuvred their satellite out of the way without requiring ESA intervention to begin with. And then when ESA had to ask they should have responded. That can't all be blamed on a faulty ticket system...
And SpaceX has designed and is implementing shade visors on all new Starlink satellites at their own expense, for the sole reason of reducing their reflection and brightness for astronomers.
No one made Elon do that, he chose to significantly increase the cost and complexity of his satellites to help astronomers.
Size matters for telescopes and there's a limit to what can be launched. Whilst Hubble provided amazing insights it can't replace all ground telescopes. Additionally ground based telescopes can be fixed and upgraded without the need for an astronaut to be flow to repair it, a capability that doesn't currently exist.
> But the black paint made the satellite thermally ‘hot’, harming its internet operations, said Patricia Cooper, SpaceX’s vice-president of satellite government affairs, at a recent webinar.
Would still be bad for astronomy but at least the impact for naked eye would be less.
In conversational English what I said is != blocks ALL light without absorbing ANY heat.
Visors block enough light to greatly reduce reflected light, and do it without substantially increasing satellite temperature. There is a thing called an insulator, which I hear can efficiently reduce the transfer of heat from things like visor to satellite.
It is also possible to absorb the heat somewhere else if you do just absorb the light.
The OIR report, if you bother to actually read it, also details that a) astronomers agree that providing world-wide broadband is a worthy cause, and b) that there is close cooperation between astronomers and at least SpaceX to work out mitigations.
What will the impact be when there are 500k+ satellites in LEO, who decides who can launch more?
On the surface this seems a wee bit absurd, but I wonder if a case could be made that it's time for more space-based telescopes.
Compared to space telescopes, ground telescopes were limited by atmospheric interference. This has improved much lately with adaptive optics. Space telescopes are better, but it's too costly. You will never see a mega telescope constellation, because there is no money to be made. Ground telescopes still generate considerable valuable data (in scientific terms. corporates wouldn't care any less). Even individuals have ground telescopes that do this. Some projects like Sloan Digital Sky Survey (https://www.sdss.org/) puts massive amounts of data in the public domain. SDSS also does observations that are impossible with space telescopes.
Space telescopes are good, but are complementary to ground telescopes - not a replacement. When (some) people say that we should simply forget ground telescopes in favor of space telescopes, they are actually asking to throw away cheap, accessible, democratic, inclusive and sometimes unique way of astronomical observations in favour of an incredibly costly, elitist and closed methods which is viable only to big corps who have little interest in it because of lack of short term profits.
An aside, there are some people in this thread asking astronomers to stop complaining and just remove the streaks from the image. I would say that's incredibly philistine stance - science has long term benefits that is underrated compared to commercially motivated projects with perceived short-term social benefits. An approach suggested is to statistically remove the streaks from image. That's against the whole purpose of these observations - astronomers are interested in the details that cannot yet be statistically predicted. Another approach is to use multiple exposures and combine them. Again - the signals they are interested in often takes night long exposure before signal is sufficiently amplified above and noise. This can't be solved with multiple exposure. The third approach is to close the sensor (usually CCD) with a shutter when a satellite is in the vicinity. This is more viable. However, this is going to be hard and is going to waste a lot of exposure time.
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.
In a comment by vilhelm_s in the previous thread has a link to a site that explain that the usual software can select correct the parts of the images and create a nice image https://skyandtelescope.org/astronomy-blogs/imaging-foundati...
It only transits the earth into a position where the sun lights it up every three years - I'm still working on finding a university to aim a spectrometer / laser at it so I can identify it's mineral composition and decide how much to charge asteroid miners for it ;)
I also hope we tax companies that launch and own satellites to fund a clean up service that de-orbits all the junk before they cause the Kessler syndrome.
That's exactly what they're doing. Starlink exists to fund Starship R&D, which will translate to much cheaper launch costs for everyone, not just astronomers.
These are low-orbit satellites and they will eventually "fly over" every point on the Earth up to their maximum inclination. Only geo-stationary satellites are "hanging above an area" and suffer from high latency because of the speed of light.
Legally speaking "airspace" does not extend beyond the atmosphere. There are treaties for this, otherwise almost all satellites would need approvals from almost all governments.
However it is supposed to work and however it does work at sea, is the situation similar for space?
> What if countries decide to extend the airspace to the aerospace?
I imagine the US would consider it an attack and retaliate (maybe economically, militarily, or covertly) against the "attacking" country.
You can find out more here: https://en.wikipedia.org/wiki/Space_law
This is basically unthinkable.
Attempting to knock down all the satellites that ever fly above your country would mean knocking down every non-geostationary satellite that ever reaches your latitude (or any latitude farther from the equator than you).
Satellites are a key part of how we all know if anyone else is launching nuclear bombs or doing anything else so stupid. In the event that a country tried this I would expect that the foreign reaction would be very extreme. In the event that a country succeeded I would put the odds of nuclear war at above 50% and of conventional war at near 100%.
On the flipside you might almost get away with knocking down a few satellites with relatively minor reactions (at least compared to war, and if you had some good justification), as long as you don't try and knock them all out...
Of course, this logic doesn't apply to suborbital flights. Any country with the means will probably just shoot down unauthorized objects on suborbital trajectory into their airspace.
Ground-based telescopes deal with objects in the sky all the time.
What makes a higher number of satellites any more problematic than those?
The sky is a noisy place. And we've had satellites up for decades. How are "megaconstellations" any different?
Can I assume that these are satellites?
It gets more interesting though. Most satellites have brightness that changes slowly as moves - due to change in illumination. But occasionally, you would find ones which dim and brighten in cycles. This indicates that the object has no attitude control and is tumbling in space. That could be a dead satellite or a rocket body. Rocket bodies are spent rocket stages which loiter in space for a while after completing its mission. Then there are flares. Some satellites (like the old Iridium constellation) occasionally reflect sunlight right at you (unlike diffuse reflections in normal sats). This is a very local event. Some flares can get brighter than any planet or stars.
It's also possible to identify what you are seeing. That used to be my hobby. You would record the time it appears, how high it gets, the direction in which it flies, how bright it gets and when it disappears. With experience, you can get a good enough estimate of the brightness (magnitude) and angles even without instruments. You would then compare it against satellite predictions like Heavens Above to identify the exact object. The one I was thrilled about was a Russian satellite powered by a nuclear reactor (a fission reactor, not a decay battery like RTG). Some of them are still in LEO (https://en.wikipedia.org/wiki/List_of_nuclear_power_systems_...).
If you google starlink satellites you can see more images
A decade ago I think my opinion would have been different, because technology didn't make offering gigabit bandwidth via wire/fiber and fixed wireless pretty straightforward. So, back then you could have argued everything was temporary. Nowadays, I suspect gigabit fiber/fixed wireless will last a very, very long time before being outmoded (if it ever is).
So, I'm asking myself whether it isn't just more sensible to put up the fixed investment to connect remote areas using existing technologies rather than blasting off satellites again and again to do it.
A few thousand satellites sounds like a lot, but the amount of ground installations that would have to be done to give the same area of access is staggering.
Oh well. Too bad nobody’s ever researched that.
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.
Maybe could be designed to act as a heat exchanger also or be used as a system to mitigate the improbable impact of a small debris
Throwing out an image or two that had a satellite or cosmic ray pass through out of a few dozen isn't so bad. But if every single one of the images has a satellite trail you may be out of luck.
If you do 500 exposures you get 500x read noise of the sensor mixed with signal. Modern CCD and CMOS sensor have low read noise (compared to thermal and shot noise) but not zero.
For scientific observations of faint objects long exposure times on order of hours are necessary, for amateur astrophotography you can just go with multiple exposures.
So instead of "How satellite ‘megaconstellations’ will photobomb astronomy images" it would be better with "Starlink satellites might interfere with space observations from Earth" or similar
This is very much not true and a remarkably narrow utilitarian view.
I understand US folks are poorly served in terms of ISP infrastructure and competition but please don't try to project those issues as a 'global' problem.
Internet service is a solved problem, you have transoceanic cables and distribution networks which garantee reliable, high bandwith, _wired_ internet service.
Wireless service is a solved problem in densely populated areas, again the issue in the US is the ludicrious pricing of mobile data plans.
The only use-cases that this serves are high-income people that want to go off-grid but are unwilling to sacrifice high-bandwith, and military deployments (Which SpaceX does not hide as an objective). To me these are very poor gains for all the negative impact it brings to science and the 'global' public.
Even in rural parts of Scandinavia where I spent my vacation, 4G signal was too weak and ISP's refuse to lay fiber unless the whole neighborhood commits to subscribe.
This may concern millions of people who need basic or better internet access, meanwhile there are only a few thousand astronomers in the world.
A satellite based internet provider is inneficiently duplicating the existing fiber/copper/cellular infrastructure but more importantly cannot scale to serve the billions of people you mention in your comment.
Do the maths you cannot keep up this alleged 50Mbps link if you add more than a few million users, there is a finite amount of satellites they can add in contiguous trajectories.
The capacity issue means this will never be affordable but to a few select few or state/defense actors.
I agree with your problem statement but this unfortunately is just not the solution.
We need to do something about millionaires. Urgently. But also global governance: space is not US's backyard.
Rich people aren't the problem themselves, a lack of regulation and taxation is. In this case, the FTC (iirc) can just approve spacex launching tens of thousands of satellites. This is weird because space is either international - so should be regulated internationally - or sovereign, the bits passing over other countries.
But the world is busy with other shit than space legislation right now so eh.
Can you elaborate what premise this conclusion follows from? And what do you want to do about them?
And going out on a limb, I would assume you have a problem with the satellites, but Amazon, SpaceX and OneWeb are companies, not a Millionaires. So maybe you meant to say we should do something about companies?
Elon Musk is CEO of SpaceX and owns > 50% of the shares. As for Blue Origin (aka Bezos / Amazon); Bezos is the owner of the company. That means these people can make decisions on their own without consulting anyone else. They appoint the board, they appoint the CEO, etc.
And sure, there are outside investors. However these investors can only marginally influence anything because they can not get a majority of share holder votes (since Bezos, Musk have > 50% shares). Maybe they got a seat on the board if their investment is large enough. But then what? They still can't get a majority in the board. Besides the only reason these investors want to participate is because the whole thing is controlled (and partially bankrolled) by Musk and Bezos.
And I'm not sure by what mechanism this will function. What will prevent a company where no individual shareholder owns >50% of shares from making a similar choice?
Not a thing I said.
> How did Amazon the company, or SpaceX the company come up with this?
Companies have employees, employees are humans with brains, they come up with ideas.
> Nothing to do with Bezos and Musk for sure?
I'm sure the normal company structures were involved in approving strategy. I doubt the idea originated with either Bezos or Musk, and not sure why their net worth has much to do with it.
If you have a problem with ambition, ambition is something many people who are not millionaires have.
The sky will probably be screwed for a while until we have a global standard.
Providing satellite internet access is a very good thing, and imposing costs on astronomy is acceptable.