An image of the Australian desert illuminates satellite pollution(thisiscolossal.com)
thisiscolossal.com
An image of the Australian desert illuminates satellite pollution
https://www.thisiscolossal.com/2025/04/a-stunning-image-of-the-australian-desert-illuminates-the-growing-problem-of-satellite-pollution/
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I think it runs off a .mov or other video file, you add black frames, etc.
I think it runs off a .mov or other video file, you add black frames, etc.
At no point does the article enlighten me of the actual ‘problem’. The photo is beautiful. The ability to even capture this signifies technological advancement, which I think wonderful.
In some way this reminds me of living in SF back in 2015, and all the arguments over the towers going up in soma. “No one wants the Manhattanization of the city” was accepted fact on both sides. Yet that wasn’t an obvious fact to me at all, and I could never find an argument in support of this ‘fact’.
Can someone enlighten me here?
In some way this reminds me of living in SF back in 2015, and all the arguments over the towers going up in soma. “No one wants the Manhattanization of the city” was accepted fact on both sides. Yet that wasn’t an obvious fact to me at all, and I could never find an argument in support of this ‘fact’.
Can someone enlighten me here?
You acknowledge the existence of things blocking <something>, and can't imagine that there are people who want to see <something>?
I feel like when <something> is the sky, potential counterpoints can't be that far. For a direct response to your question: the sky and the stars beyond have been present and visible to every human, throughout all of history- how might different people feel about it becoming obstructed? Philosophically? Emotionally? Pragmatically?
The following types of people might feel strongly about this for some reason or another- I feel like steelmaning hypothetical opinions they might have is a really enriching thing to do.
- Photographers / enthusiasts
- Astronomers / enthusiasts
- Those who enjoy nature
I personally have a mixed opinion, probably leaning towards alignment with the above groups, but I can also steelman the thought processes of those who'd think this is cool or fascinating (because of course, it is!)
I'm not trying to convince you of something about the post subject here; The rhetorical questions above are not intended to be read as "how don't you understand this and agree with me", but instead "how/why did these potential viewpoints not find you?" The lack of mention of any other viewpoint comes off as almost poor-faith or naivete.
In the SWE community, people place a lot of emphasis on attempting to find solutions to a problem yourself first, before asking a question (and detailing what you've tried/explored already) to a community. With that mentality, it irks me when I see comments that don't seem to apply the same rigor to rhetorical discussions.
At the risk of being overtly snarky, could you really not conjure anyone that might have an opposing viewpoint?
I feel like when <something> is the sky, potential counterpoints can't be that far. For a direct response to your question: the sky and the stars beyond have been present and visible to every human, throughout all of history- how might different people feel about it becoming obstructed? Philosophically? Emotionally? Pragmatically?
The following types of people might feel strongly about this for some reason or another- I feel like steelmaning hypothetical opinions they might have is a really enriching thing to do.
- Photographers / enthusiasts
- Astronomers / enthusiasts
- Those who enjoy nature
I personally have a mixed opinion, probably leaning towards alignment with the above groups, but I can also steelman the thought processes of those who'd think this is cool or fascinating (because of course, it is!)
I'm not trying to convince you of something about the post subject here; The rhetorical questions above are not intended to be read as "how don't you understand this and agree with me", but instead "how/why did these potential viewpoints not find you?" The lack of mention of any other viewpoint comes off as almost poor-faith or naivete.
In the SWE community, people place a lot of emphasis on attempting to find solutions to a problem yourself first, before asking a question (and detailing what you've tried/explored already) to a community. With that mentality, it irks me when I see comments that don't seem to apply the same rigor to rhetorical discussions.
At the risk of being overtly snarky, could you really not conjure anyone that might have an opposing viewpoint?
And fwiw, I also think the image is really cool. It's insane the world we've built, and imagining the context of all the math, physics, and human power of will that are behind those streaks of light is awesome.
But a negative viewpoint can't be that hard to see, right?
But a negative viewpoint can't be that hard to see, right?
> - Photographers / enthusiasts
Sorry, but the ship has sailed. Fix your problems in software maybe.
> - Astronomers / enthusiasts
Every Starship launch should offer ride-share for a space based observatory. Astronomy will only improve with space based telescopes. Yes, spacecraft are expensive but so are Earth based observatories, but how does it look with launch cost removed from the equation?
> - Those who enjoy nature
Generally can't see the satellites with the naked eye. Should probably concentrate on not walking into a hole / body of water / off a steep precipice.
This complaint about the aesthetics of the night sky is the wimpy enemy of progress. Imagine bronze / iron age people up in arms because suddenly the sea is full of fishing boats and merchant vessels. Or people up in arms because farmland has spoiled the view of forests.
Yes, I think this stuff looks nice without man-made things. I enjoy the night sky. I also enjoy being able to eat and utilize modern technology. There will come a day when spacecraft coming and going will be as routine as we see airplanes now, so our descendants will have that to complain about next, until it becomes as pointless to complain about as the asphalt roads that have lead to and from or houses.
Space based technology will make life better for all of humanity just like every technology that has come before it. The genie is out of the bottle and isn't going back in.
Sorry, but the ship has sailed. Fix your problems in software maybe.
> - Astronomers / enthusiasts
Every Starship launch should offer ride-share for a space based observatory. Astronomy will only improve with space based telescopes. Yes, spacecraft are expensive but so are Earth based observatories, but how does it look with launch cost removed from the equation?
> - Those who enjoy nature
Generally can't see the satellites with the naked eye. Should probably concentrate on not walking into a hole / body of water / off a steep precipice.
This complaint about the aesthetics of the night sky is the wimpy enemy of progress. Imagine bronze / iron age people up in arms because suddenly the sea is full of fishing boats and merchant vessels. Or people up in arms because farmland has spoiled the view of forests.
Yes, I think this stuff looks nice without man-made things. I enjoy the night sky. I also enjoy being able to eat and utilize modern technology. There will come a day when spacecraft coming and going will be as routine as we see airplanes now, so our descendants will have that to complain about next, until it becomes as pointless to complain about as the asphalt roads that have lead to and from or houses.
Space based technology will make life better for all of humanity just like every technology that has come before it. The genie is out of the bottle and isn't going back in.
>how does it look with launch cost removed from the equation?
The Webb Space Telescope cost $10 billion, and has a 6.5 meter mirror. With the launch cost removed, it cost $9.5 billion.
The Extremely Large Telescope is located on Earth, costs a little over $1 billion, and has a 39 meter mirror.
The idea of completely replacing ground observatories with orbital ones is so infeasible it's not really worth discussing. If satellite pollution grows so extreme they can no longer function, those capabilities will simply be lost.
The Webb Space Telescope cost $10 billion, and has a 6.5 meter mirror. With the launch cost removed, it cost $9.5 billion.
The Extremely Large Telescope is located on Earth, costs a little over $1 billion, and has a 39 meter mirror.
The idea of completely replacing ground observatories with orbital ones is so infeasible it's not really worth discussing. If satellite pollution grows so extreme they can no longer function, those capabilities will simply be lost.
The article mentions the problem ....
"....Rozells’ composite visually echoes pleas from astronomers, who warn that although satellites collect essential data, the staggering amount filling our skies will only worsen light pollution and our ability to study what lies beyond. Because this industry has little regulation, the problem could go unchecked....."
"....Rozells’ composite visually echoes pleas from astronomers, who warn that although satellites collect essential data, the staggering amount filling our skies will only worsen light pollution and our ability to study what lies beyond. Because this industry has little regulation, the problem could go unchecked....."
I realize it's a nit-pick, but that is not at all the common definition of light pollution as it relates to night skies.
It falls under clause three:
Reflected sunlight from a human object spilling light into an environment that would otherwise not have that reflected sunlight is very much in the spirit of light pollution.
It's certainly seen as such by astronomers.
What is light pollution \* Glare is the bright and uncomfortable light shining directly to the observer that interferes with your vision.
\* Light trespass is the unintended spill of artificial light into other people’s property or space and often becomes a source of conflict.
\* Skyglow is the brightening of the night sky from human-caused light scattered in the atmosphere.
Reflected sunlight from a human object spilling light into an environment that would otherwise not have that reflected sunlight is very much in the spirit of light pollution.
It's certainly seen as such by astronomers.
Skyglow is when you see the horizon light up in the direction of a city, not the light reflecting from a satellite. Look at the photo in your own link.
Let's assume I've read the link and have had discussions with both visual and radio spectrum astronomers and astrophysicists.
Starlink satellites pollute the night sky with both reflected sunlight and intended and unintended radio spectrum noise.
Manmade objects that inject light into an otherwise dark sky fit the category of skyglow, reflected sunlight tends to be sharper and less diffuse than atmospherically scattered ground lighting .. it's all extraneous human caused pollution from the PoV of telescopes.
Starlink satellites pollute the night sky with both reflected sunlight and intended and unintended radio spectrum noise.
Manmade objects that inject light into an otherwise dark sky fit the category of skyglow, reflected sunlight tends to be sharper and less diffuse than atmospherically scattered ground lighting .. it's all extraneous human caused pollution from the PoV of telescopes.
I do find the juxtaposition of “look at this image of satellites” and “the image is a composition of 360 photographs” to require a certain leap of logic that hasn’t been established. On the one hand, it shows that a lot of satellites are visible throughout the night. On the other hand it’s harder to understand what the broader implications of this are.
imagine if one of those blows up.
Now imagine the probability of the debris hitting other satellites and causing even more debris.
Finally, compare how many satellites have been launched in the past 5 years versus the rest of history.
Now imagine the probability of the debris hitting other satellites and causing even more debris.
Finally, compare how many satellites have been launched in the past 5 years versus the rest of history.
The clear grid patterns are really fantastic.
(I realise that it's bad and all that - but still, those grids are amazing to see)
Had the same thought. In a way, that photo is absolutely stunning and beautiful in its own way. But I do understand how this is a huge problem for the astronomers.
"Stitching together 343 distinct photos,"
I don't doubt that this is a real problem for astronomers and photographers, but I feel like if you had to work that hard, it doesn't really make your case.
I don't doubt that this is a real problem for astronomers and photographers, but I feel like if you had to work that hard, it doesn't really make your case.
In his defense, he was shooting a star trail. @10s per exposure, 6 per minute, becomes 360 per hour.
I believe 30s might be more appropriate for star trails which makes satellite trails oh so much more obvious. But that means a 2-3 hour session of 2 exposures per minute.
I also used to take hundreds of photos in meteor season - and having to diff between meteors and satellites was quite time consuming.
I believe 30s might be more appropriate for star trails which makes satellite trails oh so much more obvious. But that means a 2-3 hour session of 2 exposures per minute.
I also used to take hundreds of photos in meteor season - and having to diff between meteors and satellites was quite time consuming.
in photos, meteors and satellites do not look the same. satellite trails are consistent lines. meteors start small, flare in the middle, and then ends small again. they are easy for humans to distinguish, so i'd assume some software could do it as well
These photos are taken in pitch-black darkness.
You need to take a lot of exposures in order to get the data necessary to even see anything.
You need to take a lot of exposures in order to get the data necessary to even see anything.
This is a single 10sec exposure in the Aussie outback on old consumer gear ( Sony a7iii )
https://www.instagram.com/p/CersLuLBfCz
You don’t need multiples, and you don’t need an overly long exposure.
https://www.instagram.com/p/CersLuLBfCz
You don’t need multiples, and you don’t need an overly long exposure.
It sounds like you know what you're talking about until one realizes the earth is spinning. Wide field photos can be shot up to thirty seconds depending on the back and lens.
Anything more zoomy than 50mm uncropped you're getting streaks in < dozen seconds. There's a rule of thumb but I don't remember it.
Best course of action is to take a video and let a stacking program deal with it, especially if you use a real telescope.
Also the Sony a7r have like "150,000 ISO " and iirc cost like $3500 with a kit lens. That's a bit above consumer, but I may have mixed up models.
Anything more zoomy than 50mm uncropped you're getting streaks in < dozen seconds. There's a rule of thumb but I don't remember it.
Best course of action is to take a video and let a stacking program deal with it, especially if you use a real telescope.
Also the Sony a7r have like "150,000 ISO " and iirc cost like $3500 with a kit lens. That's a bit above consumer, but I may have mixed up models.
My camera is not an a7r. I paid $1200 for it used.
The exposure was 10 seconds, so by your own explanation, the spinning of the earth is not a problem ( as you can clearly see in the photo I linked )
The exposure was 10 seconds, so by your own explanation, the spinning of the earth is not a problem ( as you can clearly see in the photo I linked )
An astronomy photo can commonly require hours or even tens of hours of exposure time.
The noise from a single image of that duration would be unworkable. Even if there were no planes or satellites, nobody would take that as a single exposure.
Signal scales with exposure time, noise scales with the root of exposure time. So although the noise increases with time, the signal-noise ratio increases faster. When dealing with astronomy photos, you want to maximise SNR.
(This is a simplification, there are many types of noise including shot noise and thermal noise, but in general this is the rule of thumb you use)
(This is a simplification, there are many types of noise including shot noise and thermal noise, but in general this is the rule of thumb you use)
your method of shooting the stars with a single long exposure is called a "wide-field" image. They're cool, but if you want to get any details of anything other than the milky way you either have to track or you have to stack. that's all there is to it.
I was going off memory, and with 50mm, it looks like 10 seconds is about when you start to get streaks, assuming no cropping. I have cropped sensors so even with a 10mm lens i can only do 12-15 seconds. I have a barn door tracker, and i know how to use https://www.autostakkert.com/
you need to have black frames for it to work, and ideally a lot of them (iirc at least a half dozen if not more) - because this is how the stacker knows which pixels are noisier than other ones, and also what the thermal noise of the sensor "looks like", at least the smarter stackers use it that way. you take a bunch of pictures with the lens cap on in a dark room at around the temperature you're gunna use it at.
real amateur astrophotography is done with CCD cameras, usually monochrome with filters (or a filter wheel), done in video mode, and the frames are processed after the fact. It takes hours with clear skies to make a decent deep field astrophotograph.
I was going off memory, and with 50mm, it looks like 10 seconds is about when you start to get streaks, assuming no cropping. I have cropped sensors so even with a 10mm lens i can only do 12-15 seconds. I have a barn door tracker, and i know how to use https://www.autostakkert.com/
you need to have black frames for it to work, and ideally a lot of them (iirc at least a half dozen if not more) - because this is how the stacker knows which pixels are noisier than other ones, and also what the thermal noise of the sensor "looks like", at least the smarter stackers use it that way. you take a bunch of pictures with the lens cap on in a dark room at around the temperature you're gunna use it at.
real amateur astrophotography is done with CCD cameras, usually monochrome with filters (or a filter wheel), done in video mode, and the frames are processed after the fact. It takes hours with clear skies to make a decent deep field astrophotograph.
Tens of seconds is about right. It's something like 500/f(mm) in seconds, but you get a feel for what will blur and what won't. Here's an example I shot with a Nikkor 50mm f/1.4 @ 20s: https://www.instagram.com/p/C-mU6iIp0re/?igsh=cm16bWx1cGp3OG...
Rule of 500. Divide your lens focal length into 500. That's the longest exposure to avoid trails. 500 / 24mm = ~21s so your example would be 500 / 50mm = 10s.
Some random search result:
https://astrobackyard.com/the-500-rule/
Some random search result:
https://astrobackyard.com/the-500-rule/
No, you need to take a long exposure. Multiple exposures may improve the quality but isn’t necessary at all.
If the camera is stationary you must stack multiple short exposures to avoid star trails. You can only take long exposures with an equatorial mount.
Not if your “long” exposure is just 10s long, which is enough to get those annoying starlink trails.
Sure, 10s is certainly long enough to capture Starlink trails, though 10s exposure is not especially long for an astro photo and you would typically want to take longer exposures or stack multiple shorter ones.
For example, my Seestar S50 takes many 10-second photos to form one exposure. I would normally expect to take 1500 10-second exposures or more for a good picture, perhaps over mutiple nights (although this is very different to a wide-field image like this). A Starlink trail would be very visible in any individual frame, often brighter than stars, and I would expect to capture many individual frames containing starlink trails.
For example, my Seestar S50 takes many 10-second photos to form one exposure. I would normally expect to take 1500 10-second exposures or more for a good picture, perhaps over mutiple nights (although this is very different to a wide-field image like this). A Starlink trail would be very visible in any individual frame, often brighter than stars, and I would expect to capture many individual frames containing starlink trails.
This is not true. Image in article is taken (and stack from many images) during sunset/sunrise when satellites are lighted by sun while photographer is in dark. It's not that visible at night.
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You know those airplanes with a banner at the beach?
I can imagine a constellation of satellites writing ads (live) in space using mirrors and other nifty tech.
Unless regulation stops it.
I can imagine a constellation of satellites writing ads (live) in space using mirrors and other nifty tech.
Unless regulation stops it.
There was a Russian start up planning to do this a few years back. They had actually reached a deal with Pepsi’s Russian operations until the public backlash convinced them to find a different public relations strategy.
https://phys.org/news/2019-01-astronomers-russian-billboards...
> Unless regulation stops it.
Or a ground-based megawatt IR laser with steerable optics.
Or a ground-based megawatt IR laser with steerable optics.
Somehow, this sounds quite appealing.
I'm waiting for the dystopian SciFi novel now where earth's last survivors blast the escape route through that cloud of satellite rubbish for their Starship (TM), by use of an array of those.
One can always dream.
I'm waiting for the dystopian SciFi novel now where earth's last survivors blast the escape route through that cloud of satellite rubbish for their Starship (TM), by use of an array of those.
One can always dream.
That’s so true. I can see it too. The technology to make that must be super fun to work on but please I hope this will never happen. Can you imagine turning the whole sky as a giant pixelated screen to constantly show us ads? That’s as dystopian as it gets. Add to that the probable less than secure software to run it and hackers trying to show stuff up there. That’s something out of a Douglas Adams book. xD
earliest sci-fi antecedent i know off: https://en.wikipedia.org/wiki/The_Man_Who_Sold_the_Moon
Anyone attempting such a thing needs to be instantly put to death.
I’m fine with putting dots in the sky as a necessary side effect of providing some sort of useful service. Worldwide connectivity seems worth making astronomical observations a bit harder. But visual pollution for its own sake should be harshly discouraged.
I’m fine with putting dots in the sky as a necessary side effect of providing some sort of useful service. Worldwide connectivity seems worth making astronomical observations a bit harder. But visual pollution for its own sake should be harshly discouraged.
I don't think such a thing could hold together very long, unless it was just a string in a line. Maybe in Morse code?
With multiple launches you could probably get several parallel strings, and use it like a dot matrix printer. It would be a heck of a stunt. But I wouldn't expect it to last for more than one orbit, and only part of the planet could see it.
With multiple launches you could probably get several parallel strings, and use it like a dot matrix printer. It would be a heck of a stunt. But I wouldn't expect it to last for more than one orbit, and only part of the planet could see it.
You can change brightness and color of individual satellites as they move, so they would match the "pixel" they are in now. Just imagine swarm of very small emitting light bugs moving chaotically behind your screen and changing colors as they move from one pixel to an other. The only issue is to make sure that at every moment each pixel has enough bugs to get the required brightness.
Like regulation stopped trawling the ocean floor?
I wonder what uncontacted tribes think about starlink
If I hadn’t known what starlink was the first time I saw it, I would have assumed it was something artificial - the spacing and trajectory is far too regular to be a comet breaking up or something like that.
well, if you could observe these things with the naked eye, they might imagine it's similar to a passing meteor.
I’d be more concerned about the light pollution from the city (Perth?) on the horizon.
I'd be more concerned about both. One evil doesn't cancel the other.
I'm not. I don't regard satellites as evil. While outside last night looking at the Milky Way I spotted 2 satellites and 3 aircraft. I like seeing the satellites; I dislike that I can't see the Milky Way at home in the city due to the light pollution.
Would that be from Perth? Perth is around 180km away. Cervantes and Jurien Bay are nearby towns that could account for that light pollution.
Whataboutism.
> Rozells’ composite visually echoes pleas from astronomers, who warn that although satellites collect essential data, the staggering amount filling our skies will only worsen light pollution and our ability to study what lies beyond. Because this industry has little regulation, the problem could go unchecked.
We have the technology to put observatories in orbit, where satellite "pollution", light pollution, atmospheric effects, etc. all become significantly less problematic. Maybe that should be our focus, rather than on shaming satellite constellations for doing essential work?
We have the technology to put observatories in orbit, where satellite "pollution", light pollution, atmospheric effects, etc. all become significantly less problematic. Maybe that should be our focus, rather than on shaming satellite constellations for doing essential work?
Article with misleading conclusions.
Image is stacked from multiple images during sunset/sunrise when satellites are most visible because of sun position to observer. Photographer is in dark while satellites are lighted by direct sunlight.
During night, its barely visible.
Image is stacked from multiple images during sunset/sunrise when satellites are most visible because of sun position to observer. Photographer is in dark while satellites are lighted by direct sunlight.
During night, its barely visible.
Just paint the satellites black?
Can't tell if you're joking or not, but SpaceX has indeed been collaborating with astronomical observatories to reduce the apparent magnitude (brightness) to ground for Starlink satellites. It's not as if the potential issues weren't apparent and reported on pretty early on, ie, [0] in summer 2020 before the network entered beta. It's not perfect and the period during orbit raising before the satellites enter operational orbits is more challenging, but very significant reductions have been achieved per recs, see for example "Starlink Gen 2 Mini Satellites Photometric Characterization" [1] in 2023 and "The Brightness of Starlink Mini Satellites During Orbit-Raising" [2] in 2024:
>When magnitudes are adjusted to a uniform distance of 1000 km the means are 4.58 and 7.52, respectively. The difference of 2.94 between distance-adjusted magnitudes above and below threshold implies that mitigation is 93% effective in reducing the brightness of orbit-raising spacecraft.
So there has been progress, though more may be possible particularly as Starship gives them more mass to work with for less money. That may bring new possibilities to spend mass on "cosmetic" purposes to shade and further reduce magnitude even if it contributes nothing to the core functionality. Same as more mass may allow regulators to feasibly require higher levels of redundancy and more margin for deorbiting in case of issues or at EOL.
Of course, that does leave older unmitigated working sats contributing to light pollution for the rest of their operational lifetimes, though worth noting that one of many major advantages for low-LEO/VLEO operation is that by design such lifetimes are much shorter, and in turn generation refresh will happen more quickly. Perhaps more importantly long term, there aren't as far as I know any actual international standards and agreements towards responsible brightness mitigation (or other issues like disposing of expended upper stages responsibly, standardized end-of-life deorbiting, etc). SpaceX has, for both PR and simple corporate self-interest reasons, been a pretty good actor so far even if they get a lot of attention for being the leading first mega constellation. But I really hope follow on efforts from other players can hit the ground running with magnitude reductions at least as good, and that SpaceX itself continues to improve (or at a bare minimum not backslide).
High bandwidth fully global comms is simply too valuable a capability to really imagine going back at this point. But that's no reason not to pursue reasonable compromise mitigations, and potentially some sort of funds to ultimately create far more orbital telescopes as well as part of the package taking full advantage of what upcoming cheap megalift will make possible.
----
0: "Impact of Satellite Constellations on Optical Astronomy and Recommendations Toward Mitigations" | https://aas.org/sites/default/files/2020-08/SATCON1-Report.p...
1: https://arxiv.org/pdf/2306.06657
2: https://arxiv.org/pdf/2405.12007
>When magnitudes are adjusted to a uniform distance of 1000 km the means are 4.58 and 7.52, respectively. The difference of 2.94 between distance-adjusted magnitudes above and below threshold implies that mitigation is 93% effective in reducing the brightness of orbit-raising spacecraft.
So there has been progress, though more may be possible particularly as Starship gives them more mass to work with for less money. That may bring new possibilities to spend mass on "cosmetic" purposes to shade and further reduce magnitude even if it contributes nothing to the core functionality. Same as more mass may allow regulators to feasibly require higher levels of redundancy and more margin for deorbiting in case of issues or at EOL.
Of course, that does leave older unmitigated working sats contributing to light pollution for the rest of their operational lifetimes, though worth noting that one of many major advantages for low-LEO/VLEO operation is that by design such lifetimes are much shorter, and in turn generation refresh will happen more quickly. Perhaps more importantly long term, there aren't as far as I know any actual international standards and agreements towards responsible brightness mitigation (or other issues like disposing of expended upper stages responsibly, standardized end-of-life deorbiting, etc). SpaceX has, for both PR and simple corporate self-interest reasons, been a pretty good actor so far even if they get a lot of attention for being the leading first mega constellation. But I really hope follow on efforts from other players can hit the ground running with magnitude reductions at least as good, and that SpaceX itself continues to improve (or at a bare minimum not backslide).
High bandwidth fully global comms is simply too valuable a capability to really imagine going back at this point. But that's no reason not to pursue reasonable compromise mitigations, and potentially some sort of funds to ultimately create far more orbital telescopes as well as part of the package taking full advantage of what upcoming cheap megalift will make possible.
----
0: "Impact of Satellite Constellations on Optical Astronomy and Recommendations Toward Mitigations" | https://aas.org/sites/default/files/2020-08/SATCON1-Report.p...
1: https://arxiv.org/pdf/2306.06657
2: https://arxiv.org/pdf/2405.12007
It's not just optical pollution, the same satellites visible in the article photo over the Pinnacles are leaking radio spectrum noise into the ostensibly "Radio Quiet Zone" of the nearby Murchison that's home to cosmic microwave sensors and one regional part of the developing global SKA radio telescope platform.
This would be real simple to prove, Starlink Satelites downlink on the same band as Satelite TV so you can use the receiver from a dish that downconverts it to something a cheap dongle can handle and put that all inside a grounded, metal box in the bed of a diesel and just record spectrum.
I was under the impression that actual space business people had ways of not leaking RF when flying over.
I was under the impression that actual space business people had ways of not leaking RF when flying over.
It's been proven by several teams already, eg:
referencing: Detection of intended and unintended emissions from Starlink satellites in the SKA-Low frequency range, at the SKA-Low site, with an SKA-Low station analog (Sep. 2023)
https://arxiv.org/abs/2309.15672
It's an ongoing issue in that Starlink v1.0 leaked and as I recall promises were made that the next generation of satellites would leak less and turn off when over radio quiet zones .. that second gen group have (IIRC) more noise and continuing transmitting over RQZ's.
In new research accepted for publication in Astronomy and Astrophysics Letters, we discovered Starlink satellites are also “leaking” radio signals that interfere with radio astronomy. Even in a “radio quiet zone” in outback Western Australia, we found the satellite emissions were far brighter than any natural source in the sky.
referencing: Detection of intended and unintended emissions from Starlink satellites in the SKA-Low frequency range, at the SKA-Low site, with an SKA-Low station analog (Sep. 2023)
https://arxiv.org/abs/2309.15672
It's an ongoing issue in that Starlink v1.0 leaked and as I recall promises were made that the next generation of satellites would leak less and turn off when over radio quiet zones .. that second gen group have (IIRC) more noise and continuing transmitting over RQZ's.
> Although this IEMR abides by ITU-R guidelines, these intensities are large compared to the strongest astronomical radio sources in the sky and will therefore have the potential to disrupt astronomical observations at SKA-Low frequencies;
Sounds like the ITU-R messed up, regardless of why. starlink is 28% of the EIRP the ITU specified. And the "newer generation are a factor of 12 fainter".
We're talking micro. watts. of Effective Isotropic Radiating Power. with 0dBi antennas (unity gain).
I don't understand why they're using those oddball frequencies, but i haven't paid attention to band allocations in a long time. 159.4MHz is Land Mobile band plan - "business band 2 meters", and oh, 137.5 is "SPACE OPERATIONS". I almost want to guess that the 159.4 is a spur of something down around 39.9MHz, fourth harmonic or something. I don't see anything that would let starlink radiate there, unless they change frequencies over countries. Furthermore, it doesn't seem like the 159.4MHz signals will be a detriment to the facility in question, but merely possibly impinge on radio-astronomers.
I understand that these arrays are so sensitive that the RF they collect and process in the career of a scientist there is roughly equal to a cricket chirping once. or something. But microwatts are real tiny, too. Should be possible to put a notch filter at 137.5, or request space businesspeople to do intra-satellite on some other frequency.|
in fact, business idea: aim a yagi array where the satellites are as they pass over, can be done programmatically, or reactively - at least 4 sensors however far from the facility monitor the starlink downlink frequencies (not 137.5 and 159.4, but the ku band ones) - and then aim at the satellite.
I'll build it out with crap i have in my shed to prove it works if anyone is interested. If you know a satellite is in your second of sky, and you monitor, specifically, the 137.5 frequency with a separate, real sensitive antenna array, you can just drop the IQ/whatever from the radios for that timeframe.
This isn't rocket science, QRM and QRN will plague us forever. Thanks, Marconi.
Sounds like the ITU-R messed up, regardless of why. starlink is 28% of the EIRP the ITU specified. And the "newer generation are a factor of 12 fainter".
We're talking micro. watts. of Effective Isotropic Radiating Power. with 0dBi antennas (unity gain).
I don't understand why they're using those oddball frequencies, but i haven't paid attention to band allocations in a long time. 159.4MHz is Land Mobile band plan - "business band 2 meters", and oh, 137.5 is "SPACE OPERATIONS". I almost want to guess that the 159.4 is a spur of something down around 39.9MHz, fourth harmonic or something. I don't see anything that would let starlink radiate there, unless they change frequencies over countries. Furthermore, it doesn't seem like the 159.4MHz signals will be a detriment to the facility in question, but merely possibly impinge on radio-astronomers.
I understand that these arrays are so sensitive that the RF they collect and process in the career of a scientist there is roughly equal to a cricket chirping once. or something. But microwatts are real tiny, too. Should be possible to put a notch filter at 137.5, or request space businesspeople to do intra-satellite on some other frequency.|
in fact, business idea: aim a yagi array where the satellites are as they pass over, can be done programmatically, or reactively - at least 4 sensors however far from the facility monitor the starlink downlink frequencies (not 137.5 and 159.4, but the ku band ones) - and then aim at the satellite.
I'll build it out with crap i have in my shed to prove it works if anyone is interested. If you know a satellite is in your second of sky, and you monitor, specifically, the 137.5 frequency with a separate, real sensitive antenna array, you can just drop the IQ/whatever from the radios for that timeframe.
This isn't rocket science, QRM and QRN will plague us forever. Thanks, Marconi.
> Can't tell if you're joking or not
Not. Often obvious simple solutions are overlooked. For example, NASA spent huge sums of money trying to design a gas gauge that will work in weightless conditions. Until an engineer suggested just having a "reserve" tank that has enough to bring the spacecraft out of orbit.
Another one was NASA spend a lot of money trying to figure out how to not have the Apollo capsule overheat from the sun. The trivial solution was to make it a rotisserie, i.e. slowly rotate it.
Not. Often obvious simple solutions are overlooked. For example, NASA spent huge sums of money trying to design a gas gauge that will work in weightless conditions. Until an engineer suggested just having a "reserve" tank that has enough to bring the spacecraft out of orbit.
Another one was NASA spend a lot of money trying to figure out how to not have the Apollo capsule overheat from the sun. The trivial solution was to make it a rotisserie, i.e. slowly rotate it.
>Not. Often obvious simple solutions are overlooked.
I'm not sure I'd say "often" has something like what you offered up been overlooked by SpaceX. We're long, long past the early eras when everything was first getting figured out, and the timescales and costs are totally different. Talking of "obvious", painting something black in orbit has clear enormous thermal implications, and there are aspects of the system that seem necessarily reflective as well (solar panels, optical links and so on) and in turn mitigation requires cascading design decisions. These aren't platinum plated Apollo era programs either. Like, gut check here: do you see ANY space stations or satellites in space, at all, where they "just painted them black"? I don't think it's actually trivial at all.
Anyway main point is yes, it's recognized and yes, it's getting worked on (successfully!), and I hope that will ultimately help pave the road for any other future megaconstellation efforts by showing what's possible.
I'm not sure I'd say "often" has something like what you offered up been overlooked by SpaceX. We're long, long past the early eras when everything was first getting figured out, and the timescales and costs are totally different. Talking of "obvious", painting something black in orbit has clear enormous thermal implications, and there are aspects of the system that seem necessarily reflective as well (solar panels, optical links and so on) and in turn mitigation requires cascading design decisions. These aren't platinum plated Apollo era programs either. Like, gut check here: do you see ANY space stations or satellites in space, at all, where they "just painted them black"? I don't think it's actually trivial at all.
Anyway main point is yes, it's recognized and yes, it's getting worked on (successfully!), and I hope that will ultimately help pave the road for any other future megaconstellation efforts by showing what's possible.
I've been designing things my entire professional life, and yes, engineers overlook the obvious all the time (me too!).
I always look for simpler ways, and often enough find them.
I always look for simpler ways, and often enough find them.
That would seem to remediate one problem, but they still block the view of cameras and telescopes - worse, in a way, that they might block the view without the viewer realizing they missed the occulded star.
Even better, paint it vantablack
https://en.wikipedia.org/wiki/Vantablack
https://en.wikipedia.org/wiki/Vantablack
It should also be possible to de-orbit obsolete satellites faster if they can at end-of-life deploy a "sail" that will cause more drag.
Eddy-current-generating tethers seem a more practical option:
<https://www.colorado.edu/faculty/kantha/sites/default/files/...>
(A plot point in Neal Stephenson's Seveneves.)
<https://www.colorado.edu/faculty/kantha/sites/default/files/...>
(A plot point in Neal Stephenson's Seveneves.)
And then we have to consider what’s the effect of all those vapourised metals on the atmosphere
Probably not much. There’s already an estimated 48 tons of material falling into the atmosphere every day.
https://science.nasa.gov/solar-system/meteors-meteorites/fac...
https://science.nasa.gov/solar-system/meteors-meteorites/fac...
Might then have a lot of overheating satellites :)
Put the black surface an inch away from the satellite, supported by standoffs. That'll keep the heat away from the satellite.
Also, the black surface only needs to be on the Earth facing side.
Also, the black surface only needs to be on the Earth facing side.
It isn't that simple, is it? Even if you place the black surface on a spacer (adding mass, might I add), the black surface itself is going to radiate heat back onto the satellite via blackbody radiation. This is always going to create a worse thermal situation unless you can somehow radiate away as much heat as you could with reflections. To see what I mean, check out JWST's thermal shield.
How about something like this?
| __
| |_/\_| |
| | \/ |__|
E 1 2 3
You should check the JWST thermal shield. It addresses exactly this problem. Also keep in mind the additional cost it incurs.
Consider a shaped charge. It seems wild to me that you can direct an explosion with various shapes of the explosive. Perhaps a similar idea can apply to the blackbody radiation - get it to radiate mostly away from the satellite.
Also, the black part will be pointed at the Earth, not the Sun.
Also, the black part will be pointed at the Earth, not the Sun.
Not sure what geometry you're thinking of. Whatever idea it is, you're stuck dealing with Kirchoff's law, which says optical emissivity and absorptivity are the same number at any given wavelength. I.e., you can't create "one-way trap doors" for heat flow—that would be a Maxwell's demon. Stacking multiple surfaces isn't a way to circumvent this.
If it's just an asymmetric shape, with different material surfaces pointed in different directions, than that of course is permitted.
https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_r...
If it's just an asymmetric shape, with different material surfaces pointed in different directions, than that of course is permitted.
https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_r...
Kirchoff's law doesn't say which direction it emits in. As shaped charges can alter the direction of where the blast wave goes, I suspect an analogous behavior of a heat shield can direct where the emissions go. I.e. as you say, an asymmetric shape.
PS I haven't done thermo in nearly 50 years!
PS I haven't done thermo in nearly 50 years!
V-groove radiators are a really neat, unintuitive design, which gets strong directionality out of thermal radiation. It's the thermal design SPHEREX went with—the space telescope that went up a few weeks ago, that was all over HN.
That's: a cavity that's a thin wedge in between two slightly angled plates, where the interior surface coating is partly emissive, and partly infrared-reflective—it can reflect the thermal radiation it emits. That means specular reflections, following geometric optics, so it works like a horn for light—beams it out the sides in a narrow cone.
(.pdf) https://ttu-ir.tdl.org/server/api/core/bitstreams/71aee1e9-3...
That's: a cavity that's a thin wedge in between two slightly angled plates, where the interior surface coating is partly emissive, and partly infrared-reflective—it can reflect the thermal radiation it emits. That means specular reflections, following geometric optics, so it works like a horn for light—beams it out the sides in a narrow cone.
(.pdf) https://ttu-ir.tdl.org/server/api/core/bitstreams/71aee1e9-3...
To complicate it further I thought that some of the military sats had rotating black panels to shield them from ground visibility?
It's likely that military satellites used a bunch of tricks to hide itself. But I don't know how useful they are these days. All major space powers have radars powerful enough to easily pick them out. They're needed for satellite collision avoidance analysis.
You have to crack a few eggs to make an omelette. The benefits of satellites seem worth the cost, at least in the foreseeable future.
It is so polluted you need professional camera gear and processing of hundreds of photos together in order to show it. Get real. Internet access for poor, remote rural areas across the global is more important than convenient timelapse photography.
a) You can take these photos with a smart phone.
b) In Australia we are rolling out fibre to rural areas and are testing 10Gb plans. Starlink will never come close to those speeds.
b) In Australia we are rolling out fibre to rural areas and are testing 10Gb plans. Starlink will never come close to those speeds.
And you can see them with the naked eye. You don't even need to go anywhere terribly remote; there's sufficient darkness a 20 minute drive south of Canberra (population ~470,000, for those not familiar.)
I thought that the Australia National Broadband Network mostly services rural areas with microwave dishes (shortwave radio)? Are they changing their strategy? The original point of microwaves was to reduce cost of laying (fibre) cable. I tried to Google for any recent news about this roll-out that you speak of. Do you have a link that you can share?
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Poor, remote rural people need influencers to tell them which lambo to buy too.
The poor can't afford it. Military use is the only way Starlink will stay afloat.
You are so far from the mark out is staggering. Starlink is priced differently in different countries, and is wildly popular in developing and undeveloped countries.
A startup idea: launch satellites to capture clean night sky photos, with tiered subscription model of course.
Startup idea: launch anti-satellite satellites to de-orbit other satellites littering your airspace.
There's no concept of airspace in space. You have very few avenues to keep a sat restricted to a geographic region. Orbits like geostationary and molniya exist - but they come with their own limitations for many applications.
The concept of “airspace” is purely a legal one and exits only if your country has an air force able to enforce it (see how Israel has absolute control over Lebanese airspace), any country with anti-sattelite technology could at its disposal could declare that their airspace goes up to the geostationary orbit or even above.
Of course it would complicate the use of satellites a lot, but given their military importance it's likely that this will happen at some point when the tech is ready (by tech I mean a way to stop foreign satellites from operating without causing Kessler syndrome)
Of course it would complicate the use of satellites a lot, but given their military importance it's likely that this will happen at some point when the tech is ready (by tech I mean a way to stop foreign satellites from operating without causing Kessler syndrome)
There are soft kill mechanisms that can avoid the Kessler syndrome, at least in the beginning. But that isn't the reason why territories aren't defined beyond the atmosphere. It's easy for a plane to avoid flying over another country. But it isn't as simple for satellites to avoid flying over another nation. Orbital mechanics doesn't give you much freedom to do that. Satellites overfly hostile territories thousands of times on a daily basis. If even the countries with soft kill ASAT starts prohibiting that, then spaceflight will become untenable in less than a day. The lack of territorial claims in space is just the world nations being reasonable.
If you rely on nations being reasonable, prepare to be disappointed on a regular basis…
HN Startup idea: train a gen. AI on NASA photos and sell custom photos /s
Now (and even in 2021 it was getting hard to do that) it's impossible to do that, even with 10 second exposures.
What's needed now is multiple exposures, and merging/integrating them in something like Siril (https://siril.org/) to remove the obvious satellite trails.
However, arguably, integrating multiple exposures, while annoying and time-consuming workflow-wise (i.e. can't just look at images directly from camera, and currently need to convert to TIFF first) is often the better way to get slightly-less-noisy images anyway, and integrate effectively longer exposures without star-trails, so it's a tricky one.