Impacts of Large Satellite Constellations on Astronomy

[sebk]

To be fair Lee Jay the writing was on the wall for uninterrupted visible light telescope viewing since aeroplanes became a thing and sputnik 1 was launched. Good luck with telling China that they can't do what Russia and the west have been doing for 70 years with increased numbers of orbital objects. LEO is becoming a cheap place to place a satellite even poor countries are having them built. Ground based astronomy will have to learn to live with it.

"Good luck telling Brazil it cant chop down and burn the Amazon, so those ivory tower biologists and botanists might as well learn to live with savage deforestation anywhere else on the planet. Cannot deny people worldwide wood to heat up their homes".

"Good luck telling Japan not to kill whales or release tritiated water from Fukushima into the Pacific, so those pesky oceanographers might as well learn to live with industrial drag fishing worldwide and radioactive barrel dumping in the high seas, 50s-style. Can't deny people of healthy food, for Pete's sake are you a monster? Plus the economy needs cheap nuclear, are you a luddite?"

Enough. Please stop this disingenuous argumentation. Satellites mostly invisible to human eye are not even in the same category as deforestation of Amazon.

And releasing tritiated water is problematic or not depending on the amount of tritium actually released.  If the amount is below safe threshold it's not problematic.

[su27k]

https://twitter.com/jeff_foust/status/1536442584696070148

In a satellite constellations session at #AAS240, Pat Seitzer notes that newer (v1.5) Starlink satellites, which lack visors, are about half a magnitude brighter than earlier VisorSats. “In a real sense, we’re going backwards here.”


Seitzer adds that the proposed Starlink Gen 2 satellites, designed for launch on Starship, are far larger than existing Starlink satellites. “It’s anyone’s guess what their brightness will be.” #AAS240


However, NRAO’s Tony Beasley says that Starlink is minimizing interference in radio astronomy, with observed impacts (including testing with Starlink user terminals near observatories like the VLA) consistent with models. #AAS240


Julie Davis of the American Astronomical Society notes that astronomers’ concerns about effects of satellite constellations clash with growing demand for broadband. “We’re not against the internet, we just don’t want it to be super-reflective.” #AAS240


Seitzer: previously, outside the classified world brightness was not a design constraint for satellites. “That knowledge exists on the dark side.” #AAS240

Astronomers renew concerns about Starlink satellite brightness

Other panelists at the AAS event acknowledged that SpaceX and other companies were making efforts to reduce the brightness of their satellites. “SpaceX has put in a lot of money and person-power into solving this problem,” said Connie Walker, co-director of the International Astronomical Union’s Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference. “They’re trying again to create a mitigation strategy to lower the brightness of their satellites.”

Besides technical solutions, astronomers are also considering policy approaches. Julie Davis, an AAS public policy fellow, said that includes potential language in a wide-ranging competitiveness bill currently being negotiated by a House-Senate conference committee that would fund studies to measure the impact of satellite constellations on astronomy.

She said there was not a lot of awareness of the issue among policymakers, and that astronomers had to balance their concerns with the demand for broadband access that satellites can offer. “We need to be explicit in explaining what our problem is here. We are not against the internet, we just want it to not be super-reflective.”

[Alvian@IDN]

As Eric Ralph noted, there's going to be a better coating than Visor, at least it's the hope. Hope someone here or SpaceX can make a clarification

[su27k]

As Eric Ralph noted, there's going to be a better coating than Visor, at least it's the hope. Hope someone here or SpaceX can make a clarification

I wouldn't worry too much about this, if I'm not mistaken the "half a magnitude brighter" thing comes from unpublished result by a Russian observatory, and it's not clear what is Starlink's operational phase when they did the measurement. Also this is probably an early attempt at the new specular nadir mirror method, remember SpaceX is all about iterative development.

[Alvian@IDN]

As Eric Ralph noted, there's going to be a better coating than Visor, at least it's the hope. Hope someone here or SpaceX can make a clarification

I wouldn't worry too much about this, if I'm not mistaken the "half a magnitude brighter" thing comes from unpublished result by a Russian observatory, and it's not clear what is Starlink's operational phase when they did the measurement. Also this is probably an early attempt at the new specular nadir mirror method, remember SpaceX is all about iterative development.

What about the confirmation by Jonathan McDowell on the replies?

[su27k]

What about the confirmation by Jonathan McDowell on the replies?

See this conversation:

https://twitter.com/richard_e_cole/status/1528846125351985152

Are the observations that show the 0.5mag increase referenced in the conference?


Jonathan McDowell: No, that's based on recent MMT9 data


Thanks. Is that analysis on-line somewhere else?


Jonathan McDowell: Not yet published

MMT9 is Mini-MegaTORTORA: http://mmt9.ru

[eeergo]

Since apparently this discussion is not allowed in the General OneWeb thread, I will post it in this admittedly conflictual thread:

OneWeb backs up Starlink 5G interference warning..

Cry me a river. Now interference IS a concern.

The tune megaconstellation proponents were chiming went something like: can't hold up progress and space development for projects bringing internet to the masses, especially those most in need of it having poor or non-existent access, for the petty complaints of arrogant, entitled élites in their ivory tower (such as those travelling on the upper classes of high performance airplanes, millenials in their luxury RVs or yachts, or military corporations). After all, here they're complaining about *radio* interference, when there are other also very entitled, very out-of-touch élites whose problems were trivial, but at least complained about visible, infrared AND radio interference! Can't be that bad... surely some quick and cheap SoFtWaRe and aLgOrItHmS can do the trick and minimize or even make the interference disappear. Don't forget they're great, big private corporations, much nimbler and efficient than the fossilized big-government mammoths with their endless pessimistic analyses and regulations.

Given where 5G is going, how many people it will serve in a capillar fashion by connecting them to reliable, ultra-fast networks, using already-sold equipment that has already a huge market penetration, megaconstellation operators can only get used to it. Can't stop progress.

[SpaceCadet1980]

Since apparently this discussion is not allowed in the General OneWeb thread, I will post it in this admittedly conflictual thread:

OneWeb backs up Starlink 5G interference warning..

Cry me a river. Now interference IS a concern.

The tune megaconstellation proponents were chiming went something like: can't hold up progress and space development for projects bringing internet to the masses, especially those most in need of it having poor or non-existent access, for the petty complaints of arrogant, entitled élites in their ivory tower (such as those travelling on the upper classes of high performance airplanes, millenials in their luxury RVs or yachts, or military corporations). After all, here they're complaining about *radio* interference, when there are other also very entitled, very out-of-touch élites whose problems were trivial, but at least complained about visible, infrared AND radio interference! Can't be that bad... surely some quick and cheap SoFtWaRe and aLgOrItHmS can do the trick and minimize or even make the interference disappear. Don't forget they're great, big private corporations, much nimbler and efficient than the fossilized big-government mammoths with their endless pessimistic analyses and regulations.

Given where 5G is going, how many people it will serve in a capillar fashion by connecting them to reliable, ultra-fast networks, using already-sold equipment that has already a huge market penetration, megaconstellation operators can only get used to it. Can't stop progress.

What you are doing can't even be called comparing apples and oranges. Ignoring all of the name-calling about "elites" which is the same disparagement you have been doing all over this thread, you are also making up arguments by putting words in other people's mouths. You are equating effects that multiple scientists and organizations have described mitigation methods for with this latest stuff that there have not been suggestions of actual specific mitigations.

Contrary to your claims, 5G does not have existing sold devices that use these frequencies. What does have existing devices being used by consumers is Starlink, so your argument is entirely backwards. 5G also won't be providing service to the underserved regions like the satellite constellations. It literally is the way they tried to claim low interference levels is by not claiming service in low population areas, and while they are probably deliberately understating the areas to understate interference, there is no real reason to expect 5G to service underserved areas any more than all of the previous terrestrial systems that failed to do so. 5G has plenty of spectrum rights anyway, so it won't be blocked by not using these frequencies. This is just one company trying to repurpose their rights of a satellite band to make up for their old business model becoming obsolete, and doing this would harm other satellite applications as well.

Your continued blatantly false statements on this topic point to you just looking for excuses to match your bias.

[meekGee]

Since apparently this discussion is not allowed in the General OneWeb thread, I will post it in this admittedly conflictual thread:

OneWeb backs up Starlink 5G interference warning..

Cry me a river. Now interference IS a concern.

The tune megaconstellation proponents were chiming went something like: can't hold up progress and space development for projects bringing internet to the masses, especially those most in need of it having poor or non-existent access, for the petty complaints of arrogant, entitled élites in their ivory tower (such as those travelling on the upper classes of high performance airplanes, millenials in their luxury RVs or yachts, or military corporations). After all, here they're complaining about *radio* interference, when there are other also very entitled, very out-of-touch élites whose problems were trivial, but at least complained about visible, infrared AND radio interference! Can't be that bad... surely some quick and cheap SoFtWaRe and aLgOrItHmS can do the trick and minimize or even make the interference disappear. Don't forget they're great, big private corporations, much nimbler and efficient than the fossilized big-government mammoths with their endless pessimistic analyses and regulations.

Given where 5G is going, how many people it will serve in a capillar fashion by connecting them to reliable, ultra-fast networks, using already-sold equipment that has already a huge market penetration, megaconstellation operators can only get used to it. Can't stop progress.

What you are doing can't even be called comparing apples and oranges. Ignoring all of the name-calling about "elites" which is the same disparagement you have been doing all over this thread, you are also making up arguments by putting words in other people's mouths. You are equating effects that multiple scientists and organizations have described mitigation methods for with this latest stuff that there have not been suggestions of actual specific mitigations.

Contrary to your claims, 5G does not have existing sold devices that use these frequencies. What does have existing devices being used by consumers is Starlink, so your argument is entirely backwards. 5G also won't be providing service to the underserved regions like the satellite constellations. It literally is the way they tried to claim low interference levels is by not claiming service in low population areas, and while they are probably deliberately understating the areas to understate interference, there is no real reason to expect 5G to service underserved areas any more than all of the previous terrestrial systems that failed to do so. 5G has plenty of spectrum rights anyway, so it won't be blocked by not using these frequencies. This is just one company trying to repurpose their rights of a satellite band to make up for their old business model becoming obsolete, and doing this would harm other satellite applications as well.

Your continued blatantly false statements on this topic point to you just looking for excuses to match your bias.

Even as argumentative as I tend to be, I could not find the wherewithal to respond to eeergo's PoS comment...  Thanks for making the effort.

I sometimes can't tell if comments of that type are trolls (intended to gaslight), misleading (intended to misinform) or just plain dumb.

I'm going with door #2 on this one.

[eeergo]

Since apparently this discussion is not allowed in the General OneWeb thread, I will post it in this admittedly conflictual thread:

OneWeb backs up Starlink 5G interference warning..

Cry me a river. Now interference IS a concern.

The tune megaconstellation proponents were chiming went something like: can't hold up progress and space development for projects bringing internet to the masses, especially those most in need of it having poor or non-existent access, for the petty complaints of arrogant, entitled élites in their ivory tower (such as those travelling on the upper classes of high performance airplanes, millenials in their luxury RVs or yachts, or military corporations). After all, here they're complaining about *radio* interference, when there are other also very entitled, very out-of-touch élites whose problems were trivial, but at least complained about visible, infrared AND radio interference! Can't be that bad... surely some quick and cheap SoFtWaRe and aLgOrItHmS can do the trick and minimize or even make the interference disappear. Don't forget they're great, big private corporations, much nimbler and efficient than the fossilized big-government mammoths with their endless pessimistic analyses and regulations.

Given where 5G is going, how many people it will serve in a capillar fashion by connecting them to reliable, ultra-fast networks, using already-sold equipment that has already a huge market penetration, megaconstellation operators can only get used to it. Can't stop progress.

What you are doing can't even be called comparing apples and oranges. Ignoring all of the name-calling about "elites" which is the same disparagement you have been doing all over this thread, you are also making up arguments by putting words in other people's mouths. You are equating effects that multiple scientists and organizations have described mitigation methods for with this latest stuff that there have not been suggestions of actual specific mitigations.

Contrary to your claims, 5G does not have existing sold devices that use these frequencies. What does have existing devices being used by consumers is Starlink, so your argument is entirely backwards. 5G also won't be providing service to the underserved regions like the satellite constellations. It literally is the way they tried to claim low interference levels is by not claiming service in low population areas, and while they are probably deliberately understating the areas to understate interference, there is no real reason to expect 5G to service underserved areas any more than all of the previous terrestrial systems that failed to do so. 5G has plenty of spectrum rights anyway, so it won't be blocked by not using these frequencies. This is just one company trying to repurpose their rights of a satellite band to make up for their old business model becoming obsolete, and doing this would harm other satellite applications as well.

Your continued blatantly false statements on this topic point to you just looking for excuses to match your bias.

Strangely, my bias is shared by plenty of knowledgeable opinions in the industry (and certainly academic circles), while the *opposite bias* is usually promoted by spokesmen of a strong agenda, or is just capitalizing on lack of immediate real-world data and litigiousness spirit on the part bearing the damages.

Regarding my language: "élites" is name-calling now? Wow I must be getting old, or maybe it's the acute accent that's too posh? I'm mirroring the many comments on this thread calling astronomers "entitled group who had it good for too long" and similar. You can look them up, it's not difficult to find them in practically every page of this thread, even if a fair number of the most out-there posts, by users who anyway still keep merrily posting abundantly, were deleted. Instead, the nth message by people like meekGee (^^hi there, won't even bother answering) do use pretty straightforward swear words like *piece of shit*. Not very corageous of him to use the acronym though, must be to protect the children.

5G at those frequencies might not have existing sold devices *in the US*, but there are also other countries which use nearby frequencies within Starlink's or OneWeb's bandwidth (10.7 - 12.7 GHz) and have sold equipment with huge market penetration. I know the complaint I alluded to refers to a US spectrum litigation, but what makes it different in other parts of the planet for a service that aspires to be global from day 1 like megaconstellations, apart from not being able to influence the outcome as much there?

5G will conceivably be serving a larger amount of people who might otherwise not have access to reliable internet, regardless of them living in crowded areas, because they might not be able to afford good quality, high-speed service with current networks, or they might get saturated by top users otherwise. If we're gauging a system as preferential by the size of its user base, megaconstellations serving a few million people should yield way hard to 5G serving hundreds of millions of them, if not billions. Moreover, with 5G being short-range and intended for high-density areas, as you point out, remote underserved areas should get minimal interference by definition! Are you sure I'm the one with the backwards argument?

As for the need to change out the satellites if the 5G proponents get their way, I thought one of the strongest selling points for megaconstellations was that they were cheaper than less damaging terrestrial alternatives, hardware was inexpensive and easily upgradable (some may say demisable). Now their business model becomes obsolete if someone else dares as much as touch the fringe of their spectrum in areas where they don't intend their main business to lie.

[meekGee]

Since apparently this discussion is not allowed in the General OneWeb thread, I will post it in this admittedly conflictual thread:

OneWeb backs up Starlink 5G interference warning..

Cry me a river. Now interference IS a concern.

The tune megaconstellation proponents were chiming went something like: can't hold up progress and space development for projects bringing internet to the masses, especially those most in need of it having poor or non-existent access, for the petty complaints of arrogant, entitled élites in their ivory tower (such as those travelling on the upper classes of high performance airplanes, millenials in their luxury RVs or yachts, or military corporations). After all, here they're complaining about *radio* interference, when there are other also very entitled, very out-of-touch élites whose problems were trivial, but at least complained about visible, infrared AND radio interference! Can't be that bad... surely some quick and cheap SoFtWaRe and aLgOrItHmS can do the trick and minimize or even make the interference disappear. Don't forget they're great, big private corporations, much nimbler and efficient than the fossilized big-government mammoths with their endless pessimistic analyses and regulations.

Given where 5G is going, how many people it will serve in a capillar fashion by connecting them to reliable, ultra-fast networks, using already-sold equipment that has already a huge market penetration, megaconstellation operators can only get used to it. Can't stop progress.

What you are doing can't even be called comparing apples and oranges. Ignoring all of the name-calling about "elites" which is the same disparagement you have been doing all over this thread, you are also making up arguments by putting words in other people's mouths. You are equating effects that multiple scientists and organizations have described mitigation methods for with this latest stuff that there have not been suggestions of actual specific mitigations.

Contrary to your claims, 5G does not have existing sold devices that use these frequencies. What does have existing devices being used by consumers is Starlink, so your argument is entirely backwards. 5G also won't be providing service to the underserved regions like the satellite constellations. It literally is the way they tried to claim low interference levels is by not claiming service in low population areas, and while they are probably deliberately understating the areas to understate interference, there is no real reason to expect 5G to service underserved areas any more than all of the previous terrestrial systems that failed to do so. 5G has plenty of spectrum rights anyway, so it won't be blocked by not using these frequencies. This is just one company trying to repurpose their rights of a satellite band to make up for their old business model becoming obsolete, and doing this would harm other satellite applications as well.

Your continued blatantly false statements on this topic point to you just looking for excuses to match your bias.

Strangely, my bias is shared by plenty of knowledgeable opinions in the industry (and certainly academic circles), while the *opposite bias* is usually promoted by spokesmen of a strong agenda, or is just capitalizing on lack of immediate real-world data and litigiousness spirit on the part bearing the damages.

Regarding my language: "élites" is name-calling now? Wow I must be getting old, or maybe it's the acute accent that's too posh? I'm mirroring the many comments on this thread calling astronomers "entitled group who had it good for too long" and similar. You can look them up, it's not difficult to find them in practically every page of this thread, even if a fair number of the most out-there posts, by users who anyway still keep merrily posting abundantly, were deleted. Instead, the nth message by people like meekGee (^^hi there, won't even bother answering) do use pretty straightforward swear words like *piece of shit*. Not very corageous of him to use the acronym though, must be to protect the children.

5G at those frequencies might not have existing sold devices *in the US*, but there are also other countries which use nearby frequencies within Starlink's or OneWeb's bandwidth (10.7 - 12.7 GHz) and have sold equipment with huge market penetration. I know the complaint I alluded to refers to a US spectrum litigation, but what makes it different in other parts of the planet for a service that aspires to be global from day 1 like megaconstellations, apart from not being able to influence the outcome as much there?

5G will conceivably be serving a larger amount of people who might otherwise not have access to reliable internet, regardless of them living in crowded areas, because they might not be able to afford good quality, high-speed service with current networks, or they might get saturated by top users otherwise. If we're gauging a system as preferential by the size of its user base, megaconstellations serving a few million people should yield way hard to 5G serving hundreds of millions of them, if not billions. Moreover, with 5G being short-range and intended for high-density areas, as you point out, remote underserved areas should get minimal interference by definition! Are you sure I'm the one with the backwards argument?

As for the need to change out the satellites if the 5G proponents get their way, I thought one of the strongest selling points for megaconstellations was that they were cheaper than less damaging terrestrial alternatives, hardware was inexpensive and easily upgradable (some may say demisable). Now their business model becomes obsolete if someone else dares as much as touch the fringe of their spectrum in areas where they don't intend their main business to lie.

Based on the first paragraph, definitely door #2 now.   (I'd argue on the merits of your post but I just can't find any.)

[spacenut]

Space satellites such as Hubble and Webb are much better than any terrestrial telescopes.  I say put more space telescopes up for all to use.  Put them on the back side of the moon. 

I would also think a person using a telescope can distinguish between a fast moving satellite and what they are looking at that is mostly stationary. 

More satellites are going up, not only by SpaceX and OneWeb, but other foreign countries will be putting more up.  Near earth space is going to get crowded.

[Lee Jay]

Space satellites such as Hubble and Webb are much better than any terrestrial telescopes.

Not at everything, and they tend to cost orders of magnitude more than terrestrial scopes of the same size.

[Robotbeat]

Space satellites such as Hubble and Webb are much better than any terrestrial telescopes.

Not at everything, and they tend to cost orders of magnitude more than terrestrial scopes of the same size.

For the same size, yes at everything. True about the last part. …for now.

[Lee Jay]

Space satellites such as Hubble and Webb are much better than any terrestrial telescopes.

Not at everything, and they tend to cost orders of magnitude more than terrestrial scopes of the same size.

For the same size, yes at everything. True about the last part. …for now.

Okay, but how many 8.2m telescopes are in space?  Zero.  How many 20-30m space telescopes are under construction?  Also zero.  This multitude of large terrestrial scopes - which all together cost around the same as JWST - can combine to scan and map orders of magnitude more sky in the same period of time.  Further, with adaptive optics they can almost match the narrow-field resolving power of space telescopes and with far larger apertures, they can exceed that resolving power. So, for the same money, you get a lot more capability in areas other than wavelengths that don't make it through the atmosphere.

And don't kid yourself.  Telescopes like the Subaru, VLT, GMT and EELT aren't going to space anytime soon.

[jebbo]

Okay, but how many 8.2m telescopes are in space? 

Don't forget the 10m class instruments like Hobby-Eberly and GTC 

Snippety, snip

And don't kid yourself.  Telescopes like the Subaru, VLT, GMT and EELT aren't going to space anytime soon.

Indeed.

I'm not keen on the entire "space telescopes are much better" argument. They aren't wavelength and seeing limited by the atmosphere but aside from that, ground instruments have many advantages in cost, construction, maintenance, upgrades, repair, flexibility, etc.

As you say, there are also *LOTS* of them and - given costs (which aren't launch price driven) - it is hard to envision replacing the gamut of 8m+ instruments with similar space-based instruments; let alone the huge numbers of smaller instruments (most RV planet hunters are <4m).

Personally, I'm a fan of lunar instruments but these don't really garner any advantage until there are enough people there to replicate the stuff we can do here.

I've attached a summary of some of the differences between environments ... but it's way more complex that this but hard to express succinctly in powerpoint 

--- Tony

[Lee Jay]

Okay, but how many 8.2m telescopes are in space? 

Don't forget the 10m class instruments like Hobby-Eberly and GTC 

And Keck!

Snippety, snip

And don't kid yourself.  Telescopes like the Subaru, VLT, GMT and EELT aren't going to space anytime soon.

Indeed.

I'm not keen on the entire "space telescopes are much better" argument. They aren't wavelength and seeing limited by the atmosphere but aside from that, ...

Okay, but the wavelength thing is kind of massive.  You can't do JWST on the ground.

[Robotbeat]

Space satellites such as Hubble and Webb are much better than any terrestrial telescopes.

Not at everything, and they tend to cost orders of magnitude more than terrestrial scopes of the same size.

For the same size, yes at everything. True about the last part. …for now.

Okay, but how many 8.2m telescopes are in space?  Zero.  How many 20-30m space telescopes are under construction?  Also zero.  This multitude of large terrestrial scopes - which all together cost around the same as JWST - can combine to scan and map orders of magnitude more sky in the same period of time.  Further, with adaptive optics they can almost match the narrow-field resolving power of space telescopes and with far larger apertures, they can exceed that resolving power. So, for the same money, you get a lot more capability in areas other than wavelengths that don't make it through the atmosphere.

And don't kid yourself.  Telescopes like the Subaru, VLT, GMT and EELT aren't going to space anytime soon.

They certainly won’t without vehicles like Starship, which depend on Starlink for viability.

[Robotbeat]

People used to say the whole “don’t kid yourself” line about megaconstellations (“Teledesic failed! Just not viable.”) And then Starlink/OneWeb happened.

Patronizing defeatism.

[edkyle99]

People used to say the whole “don’t kid yourself” line about megaconstellations (“Teledesic failed! Just not viable.”) And then Starlink/OneWeb happened.

Patronizing defeatism.

OneWeb went bankrupt and is now living on bailout funding, so skepticism seems warranted.  Is Starlink profitable yet?  Probably not given this start up cost phases (they have 400,000 customers but want 40 million).  It must have a good chance at future profitability or SpaceX wouldn't be so committed.  In addition, the satellite mass production line is winning the company other, DoD work, which may pay off bigger.

 - Ed Kyle