Astronomers Despair as Starlink Train Ruins Observation of Nearby Galaxies(forbes.com)
forbes.com
Astronomers Despair as Starlink Train Ruins Observation of Nearby Galaxies
https://www.forbes.com/sites/jonathanocallaghan/2019/11/18/this-is-not-coolastronomers-despair-as-spacex-starlink-train-ruins-observation-of-nearby-galaxies/#4601f3666538
112 comments
> Personally, I think the benefit of truly global broadband internet from space is worth the cost of an hour of observing time per night.
SpaceX isn't the going to be the last company or nation state to put up a network of satellites like this.
SpaceX isn't the going to be the last company or nation state to put up a network of satellites like this.
Do you have any reason to believe that additional satellites would alter the geometry of the Earth so that they would be visible for longer after sunset?
Satellites at higher orbit will be visible longer after sunset, both because they'll be in sunlight for a larger part of their orbit and because they'll be visible (above the horizon) to observers further away. The train is currently at about half of the satellites' intended final altitude.
would larger objects, or ones at a larger orbit be visible longer?
admittedly, i dont know much about space stuffs. :)
admittedly, i dont know much about space stuffs. :)
at a higher orbit their brightness will be less, but they will be illuminated longer and visible from more of the planet. Assuming a constant average reflectivity, larger objects will be more visible.
This is what concerns me - either a tragedy of the commons as multiple companies and countries rush to be players in this market, or a monopoly for the first mover.
I would prefer some sort of global co-operative effort with standards and oversight so satellites are interchangeable, and supplied/deployed under a contract which shares the revenue.
I would prefer some sort of global co-operative effort with standards and oversight so satellites are interchangeable, and supplied/deployed under a contract which shares the revenue.
the satellites will be in Earth's shadow and not visible at all
They're not transparent, but they might as well be. They are small and very far away and most importantly moving at extremely high speed. I calculate that a satellite could obscure a small object of interest for at most a few microseconds. Considering that astronomy exposure times are often measured in minutes, this is absolutely a non-issue.
are them visible by naked eye? site indicates a good opportunity at a not too bad of a time
They may be, depending on their orientation and position relative to the sun. I haven't seen them yet myself, but there are plenty of reports and videos of people seeing them. I haven't yet figured out how to accurately calculate how bright they will be.
That website is very cool.
I understand that the astronomers are disappointed, but isn’t that because the period we are in right now is immediately before it becomes 10x cheaper to launch telescopes into space?
Won’t it be so much better to observe directly from space as opposed to from the earth?
Can anyone comment on this?
Can anyone comment on this?
Not since the advent of modern adaptive optics[1]. Ground-based telescopes now outperform space telescopes in the visible spectrum[2]. For as long as the cost per kilo to orbit is higher than the cost per kilo to the Atacama desert, ground-based astronomy is going to be superior.
The other great advantage of ground-based telescopes is that _they're easy to fix and improve_. The iteration loop is that you walk into the dome and you fiddle with things. You don't need multiple years of planning to polish a mirror. There's an excellent Twitter thread on this issue here[3].
[1] https://en.wikipedia.org/wiki/Adaptive_optics
[2] https://astronomynow.com/2018/07/19/adaptive-optics-tomograp...
[3] https://twitter.com/cynosurae/status/1196567663977230336
The other great advantage of ground-based telescopes is that _they're easy to fix and improve_. The iteration loop is that you walk into the dome and you fiddle with things. You don't need multiple years of planning to polish a mirror. There's an excellent Twitter thread on this issue here[3].
[1] https://en.wikipedia.org/wiki/Adaptive_optics
[2] https://astronomynow.com/2018/07/19/adaptive-optics-tomograp...
[3] https://twitter.com/cynosurae/status/1196567663977230336
Perhaps a deal could be worked out where the satellite companies also have to launch Atacama-scale telescopes, where Musk et al have to pay for the difference in cost between Atacama and orbit.
Telescopes are pretty big. It would take 5-10 Falcon 9 launches to put something with that mass into orbit (although in space you could probably have a lighter mechanism for orienting el/az). The telescope's mirror is also too big to physically fit into the F9's fairing.
Once you get it there, you need to assemble it and keep it running. Maintenance is a real doozy— building a telescope on Earth is expensive. Building a telescope in space is even harder, since it won't be regularly serviced and you have to overengineer it. A typical space telescope still costs an order of magnitude more than a recordbreakingly expensive earth-based one.
Once you get it there, you need to assemble it and keep it running. Maintenance is a real doozy— building a telescope on Earth is expensive. Building a telescope in space is even harder, since it won't be regularly serviced and you have to overengineer it. A typical space telescope still costs an order of magnitude more than a recordbreakingly expensive earth-based one.
Yes but the point of Starlink is to fund Starship, which is a lot bigger than Falcon 9. Its fairing is 9 meters in diameter[0], large enough for all but the top six land-based telescopes.[1] Its payload is 100+ tonnes, five times larger than Falcon 9's.
Starship is also a lot cheaper per kilogram of payload; at scale, as low as $20/kg. Cheap launch also makes your satellites cheaper to build, since it's less of a disaster if you have to replace them.
Musk has already floated the idea of building a second-generation Starship with an 18-meter fairing.[2]
[0] https://www.spacex.com/starship
[1] https://en.wikipedia.org/wiki/List_of_largest_optical_reflec...
[2] https://www.teslarati.com/spacex-elon-musk-starship-the-next...
Starship is also a lot cheaper per kilogram of payload; at scale, as low as $20/kg. Cheap launch also makes your satellites cheaper to build, since it's less of a disaster if you have to replace them.
Musk has already floated the idea of building a second-generation Starship with an 18-meter fairing.[2]
[0] https://www.spacex.com/starship
[1] https://en.wikipedia.org/wiki/List_of_largest_optical_reflec...
[2] https://www.teslarati.com/spacex-elon-musk-starship-the-next...
Even if it becomes physically possible to launch them at some point in the future, I should have mentioned that launch costs are only a relatively small part of the cost of space based telescopes. As launch prices continue to go down, this will be more and more true in the future. For the upcoming JWST, the launch is only costing around 1-2% of the overall price. It will be a similar number for WFIRST if that gets built on budget. The expensive part is engineering a device that can assemble itself in outer space, and continue to run 24/7 for decades without regular maintainence.
This is outdated model regarding space telescopes.
With radically cheaper launches, it's becoming quite possible - not now, but somewhat soon - to actually service telescopes, with conditions superior to those under which the Hubble was serviced by Shuttle teams.
With radically cheaper launches, it's not necessary to ensure the 'scope runs 24/7 for decades without regular maintenance. It can even be replaced regularly; including by bringing it to Earth, servicing it and sending back.
Launch prices are going to drop, but so is the necessity to be extremely reliable for the space equipment, for the same two reasons: 1) it's comparatively easy to get to it for a service and 2) it's comparatively easy to just send a replacement if needed.
With space manufacturing advancements still ahead of us - we didn't really experimented with making telescopes in orbit - it's not clear if space telescopes won't outperform terran ones. Space telescopes are going to have advantages like "atmosphere doesn't block part of the spectrum" and "there is no need to make a big structure capable withstanding 1g gravity".
It's still crucially important to be able to do terran-based astronomy, and that's a problem, but there is no doubt that the astronomy revolution which started with Hubble still has major advancements to have in the near future.
With radically cheaper launches, it's becoming quite possible - not now, but somewhat soon - to actually service telescopes, with conditions superior to those under which the Hubble was serviced by Shuttle teams.
With radically cheaper launches, it's not necessary to ensure the 'scope runs 24/7 for decades without regular maintenance. It can even be replaced regularly; including by bringing it to Earth, servicing it and sending back.
Launch prices are going to drop, but so is the necessity to be extremely reliable for the space equipment, for the same two reasons: 1) it's comparatively easy to get to it for a service and 2) it's comparatively easy to just send a replacement if needed.
With space manufacturing advancements still ahead of us - we didn't really experimented with making telescopes in orbit - it's not clear if space telescopes won't outperform terran ones. Space telescopes are going to have advantages like "atmosphere doesn't block part of the spectrum" and "there is no need to make a big structure capable withstanding 1g gravity".
It's still crucially important to be able to do terran-based astronomy, and that's a problem, but there is no doubt that the astronomy revolution which started with Hubble still has major advancements to have in the near future.
Radically cheaper launches will still be significantly more expensive than current maintenance contracts. Even if we have infinitely reusable rockets in the future, you're still looking at millions of $ in fuel costs for a servicing trip. I am personally not as optimistic about "soon".
If you send a technician out to the Earth-Sun L2 point (where JWST will be) so that she can throw some grease on a gear or spray WD-40 on a reaction wheel, she'll be 4 times further from Earth than any human has ever gone. Although there may be some synergy with future Lunar/Martian missions, there's a lot of work that needs to be done to figure out how to do that safely. I think L2 is the safest Lagrange point w.r.t radiation, but it's still potentially deadly.
>"there is no need to make a big structure capable withstanding 1g gravity".
While the overall structure may not need to withstand 1g continuously, you still need to design it to as much as 6 Gs of acceleration during launch (as well as significant lateral acceleration, and occasional shocks in the dozens or hundreds of gs).
If you send a technician out to the Earth-Sun L2 point (where JWST will be) so that she can throw some grease on a gear or spray WD-40 on a reaction wheel, she'll be 4 times further from Earth than any human has ever gone. Although there may be some synergy with future Lunar/Martian missions, there's a lot of work that needs to be done to figure out how to do that safely. I think L2 is the safest Lagrange point w.r.t radiation, but it's still potentially deadly.
>"there is no need to make a big structure capable withstanding 1g gravity".
While the overall structure may not need to withstand 1g continuously, you still need to design it to as much as 6 Gs of acceleration during launch (as well as significant lateral acceleration, and occasional shocks in the dozens or hundreds of gs).
Also we are gone move into types of systems where its not one thing anymore. We increasingly telescopes that are consistent of multiple parts sometimes including things like a sun shade that operates far away from the rest of the parts.
All of these things are only gone be possible once launch prices are cheaper and Starlink (or something like it) is a major part of how that can happen.
All of these things are only gone be possible once launch prices are cheaper and Starlink (or something like it) is a major part of how that can happen.
You don't need much orbital assembly if you can launch something with a 9-meter or 18-meter diameter. And again, cheaper launch cost also makes space hardware cheaper; you can afford to make it heavier, and you can afford to replace it if necessary.
Adaptive optics should be able to adapt to any number of satellites traveling, quite predictably and diminutively through their frame of capture.
That is not remotely what "adaptive optics" means. Word arguments like that degrade the quality of debate.
In case the commenter isn't aware, adaptive optics compensate for the shimmer of the atmosphere, not the presence of light-scattering objects between the telescope and a dim object part-way across the universe.
Relevant light scattering occurs in the atmosphere between the satellite and the telescope. It also occurs between every other light source, across the universe, and the telescope. Thats why the satellites contribution to light scattering is tiny. Even in the morning where one might catch the sun - the sky is already lightened.
Hard or soft optical adaptations to remove atmospheric distortions are far more demanding than processing required to remove low magnitude satellite trails, which is already developed and required on occasion.
Hard or soft optical adaptations to remove atmospheric distortions are far more demanding than processing required to remove low magnitude satellite trails, which is already developed and required on occasion.
Im broadly aware of a range of techniques which can be involved in adaptive optics. The quality of debate seems very low to me and not worth laboring words on when people are imagining low power satellite trails represent a big challenge to astronomical image clarity.
Signal to noise ratio is the limiting factor in these observations. Decrease the signal and suddenly whole sets of galaxies fall below the noise floor.
I have not seen any information that light from these satellites could scatter and brighten the night sky a significant amount. This article just shows their paths are visible on a sensitive image, but the paths themselves amount to tiny fraction of the image. There is no claim they added significantly to the overall exposure. With their being bright planets and stars already present in the sky, I don't expect they could.
How much do you think all the sunk infrastructure costs of existing telescopes cost, and how many years did it take to build them?
The bigger telescopes today have primary reflectors that are vastly bigger than the James Webb Space Telescope: for example the Large Binocular Telescope with its 8.4 metre mirrors, or the Extremely Large Telescope (currently under construction: first light due in 2024) with its 39.2 metre segmented priary. Even the segmented designs weigh hundreds of tons; these instruments are too big and heavy to put in orbit even with SpaceX's Superheavy/Starship.
If the light pollution from Starlink can't be mitigated, it'll be necessary to replace dozens of hundred million dollar to billion dollar instruments which took years or decades to build, at a post potentially greater than the entire consat cluster.
The bigger telescopes today have primary reflectors that are vastly bigger than the James Webb Space Telescope: for example the Large Binocular Telescope with its 8.4 metre mirrors, or the Extremely Large Telescope (currently under construction: first light due in 2024) with its 39.2 metre segmented priary. Even the segmented designs weigh hundreds of tons; these instruments are too big and heavy to put in orbit even with SpaceX's Superheavy/Starship.
If the light pollution from Starlink can't be mitigated, it'll be necessary to replace dozens of hundred million dollar to billion dollar instruments which took years or decades to build, at a post potentially greater than the entire consat cluster.
However, sunk costs are sunk costs. There's a reason we have that term in economics in the first place.
It is hard to estimate the cost of replacing LSST with something off-planet. As it, alone, costs ~billions, putting a similar instrument in space costs far, far more.
Furthermore, dark skies are a resource for all of humanity, not just astronomers.
Furthermore, dark skies are a resource for all of humanity, not just astronomers.
The Starlink project doesn't actually threaten dark skies. The satellites spend most of their night-side transit in Earth's shadow.
Indeed, a lack of dark shy makes the Starlink constellation harder to see from the ground.
Indeed, a lack of dark shy makes the Starlink constellation harder to see from the ground.
That's like saying arson is no problem, the cost of the building was a sunk cost anyway.
Arson adds no value. The value trade-off of slightly decreased telescope efficiency and ubiquitous internet access is a lot more positive.
What's more important? Global internet access for the rest of the world population or a few dozen telescopes? Imo internet access is going to have immediate positive impact for billions of global disconnected poor.
I'm sure I could make better use of your home by demolishing it and erecting a homeless hostel. Isn't that more important than your prior claim to live there?
(This is a m-e-t-a-p-h-o-r, not a literal proposal, but what Starlink is doing to astronomy on a global scale is pretty much equivalent. The onus should be on Starlink to (a) not do that, or (b) pay for complete relocation or replacement of the telescopes they've just wrecked. Yes, that's a lot of money. Boo hoo ...)
(This is a m-e-t-a-p-h-o-r, not a literal proposal, but what Starlink is doing to astronomy on a global scale is pretty much equivalent. The onus should be on Starlink to (a) not do that, or (b) pay for complete relocation or replacement of the telescopes they've just wrecked. Yes, that's a lot of money. Boo hoo ...)
019djen2lsls(1)
> The onus should be on Starlink to (a) not do that
Why? Astronomers have no more claim to ownership of the sky than Starlink does.
Why? Astronomers have no more claim to ownership of the sky than Starlink does.
Astronomers are not changing anything IN the sky, Starlink does?
The sky changes all the time. Astronomers are observers, and it seems the onus should be on the observer to change the way they interpret the observation if the observable changes. We didn't kill radio stations (or microwave ovens) to make sure that radio telescopes can do their jobs [https://xkcd.com/2226/].
Isn't there a "security-zone" around the large radio-telescopes where usage of most electronic devices is forbidden?
> Imo internet access is going to have immediate positive impact for billions of global disconnected poor.
do you really think that? is that why companies like facebook are so interested in third-world markets? or is it because they want to elevate their ability to siphon user data and hack human emotions to become addicted for more and more money, and also that facebook wants there to be little distinction between them and and the internet in these markets?
i don't think the internet has had as big of a positive impact on society as people think it has. in no other time in history has there existed such a powerful medium for control and manipulation.
and this is ignoring the fact that most of elon's projects are born out of narcissism and hubris.
do you really think that? is that why companies like facebook are so interested in third-world markets? or is it because they want to elevate their ability to siphon user data and hack human emotions to become addicted for more and more money, and also that facebook wants there to be little distinction between them and and the internet in these markets?
i don't think the internet has had as big of a positive impact on society as people think it has. in no other time in history has there existed such a powerful medium for control and manipulation.
and this is ignoring the fact that most of elon's projects are born out of narcissism and hubris.
Why not have both?
Space telescopes are objectively superior in every single way. It's like a photograph under clear conditions vs a photograph in fog. Look at Hubble vs much larger terrestrial scopes. Starship's booster could launch something much larger than Hubble at a fraction of the cost.
That's not really true anymore. In the last few years adaptive optics has closed the gap.
source: https://www.popularmechanics.com/space/a22240382/neptune-gro...
source: https://www.popularmechanics.com/space/a22240382/neptune-gro...
1) Atmosphere blocks parts of the electromagnetic spectrum, so not all telescopes on Earth will be on the level field with space-based ones.
2) Earth-based telescopes have to withstand gravity of 1g, while in space you can have some bigger structures.
2) Earth-based telescopes have to withstand gravity of 1g, while in space you can have some bigger structures.
And if Starlink inconveniences astronomy, it probably won't take but so many further years before adaptive signal correction algorithms close the gap again.
I can't comment on that specifically (telescopes in orbit, I invite others to). My two cents though are this: I frequently go on multi-day backpacking trips just to get away from it all. I can get so far out when the only human-made anything that I see are the occasional aircraft and the occasional satellite. It's a great disconnect -- I can pretend that the modern world doesn't exist. It would be a great disappointment to me if the evening/morning sky were to become so populated that there were constant reminders of the modern & interconnected world. I would be resentful of whoever ruined that for me, everyone else, and generations to come.
On these trips, do you bring an emergency radio or GPS?
Typically, no, but sometimes yes . It depends on how well I know the area (if at all), how far from the road, how many people are coming with, etc...I have a Yaseu FT-60, but (a) Don't have HAM license and (b) It's too heavy. I never take a GPS map, but sometimes I take an emergency GPS emergency locator (e.g. SPOT).
On one hand, yes, you're entirely right about the eventual outcome, but on the other hand, let's get there gracefully. The article describes an event akin to commercial light pollution or commercial aviation, with the similar cause of private industry charging ahead of regulation and standards. It could be that the only solution is to quickly act to regulate space more completely, but we don't have a healthy international political climate for such regulation right now.
Also, in terms of quality of evidence, there is sadly a relatively strong pseudoscientific strain of thought that denies any astronomy done from space. If we stop taking high-quality photos from the surface of the Earth using relatively mundane methods, then the flat-Earthers win.
Finally, what if Kessler Syndrome sets in? In that case, it would not be cheaper to launch a telescope into space, even if the telescope is destined for a relatively distant place like a Lagrange point, since it first must run a gauntlet of debris. Meanwhile, observations from the ground would certainly be twinklier and noisier but not especially more expensive.
Also, in terms of quality of evidence, there is sadly a relatively strong pseudoscientific strain of thought that denies any astronomy done from space. If we stop taking high-quality photos from the surface of the Earth using relatively mundane methods, then the flat-Earthers win.
Finally, what if Kessler Syndrome sets in? In that case, it would not be cheaper to launch a telescope into space, even if the telescope is destined for a relatively distant place like a Lagrange point, since it first must run a gauntlet of debris. Meanwhile, observations from the ground would certainly be twinklier and noisier but not especially more expensive.
> On one hand, yes, you're entirely right about the eventual outcome, but on the other hand, let's get there gracefully.
The problem with a "get there gradually" approach (at least as I understand it, and I may not have understood you correctly) is that it pretty much precludes a useful LEO constellation.
A LEO constellation is not really useful unless it has a significant number of satellites. Putting up 1% of the satellites doesn't really get you 1% of the functionality of the system. There's a minimum threshold you have to hit for the system to really be viable at all.
Which means at _some_ point (if we have LEO constellations at all) we're going to have to really rapidly go from very few LEO satellites to a large number.
The problem with a "get there gradually" approach (at least as I understand it, and I may not have understood you correctly) is that it pretty much precludes a useful LEO constellation.
A LEO constellation is not really useful unless it has a significant number of satellites. Putting up 1% of the satellites doesn't really get you 1% of the functionality of the system. There's a minimum threshold you have to hit for the system to really be viable at all.
Which means at _some_ point (if we have LEO constellations at all) we're going to have to really rapidly go from very few LEO satellites to a large number.
> in terms of quality of evidence, there is sadly a relatively strong pseudoscientific strain of thought that denies any astronomy done from space. If we stop taking high-quality photos from the surface of the Earth using relatively mundane methods, then the flat-Earthers win.
This isn't a real problem with the quality of the photos. Such people should be kept out of power and otherwise ignored.
> what if Kessler Syndrome sets in?
Starlink can't result in Kessler Syndrome. The time it takes orbits to decay from that altitude is measured in single-digit years.
This isn't a real problem with the quality of the photos. Such people should be kept out of power and otherwise ignored.
> what if Kessler Syndrome sets in?
Starlink can't result in Kessler Syndrome. The time it takes orbits to decay from that altitude is measured in single-digit years.
Of all the political groups that we should be worried about catering to regarding best course of action for deployment of space communication tools, the flat-Earthers should be at the absolute bottom of the concern pile.
Launch costs are not the dominant cost of building space telescopes, which are ~10x more expensive than equivalent ground-based systems (when they exist).
Ground-based telescopes built in the 1940s are still being used for cutting-edge science today because it's simple and cheap to upgrade their instruments. That's not possible in space--when JWST runs out of propellant, it becomes just a $10B piece of space junk.
Ground-based telescopes built in the 1940s are still being used for cutting-edge science today because it's simple and cheap to upgrade their instruments. That's not possible in space--when JWST runs out of propellant, it becomes just a $10B piece of space junk.
Moon based telescopes then. Let's do it!
Putting a person on the moon cost a significant fraction of the US GDP.
The tax burden required to move Earth's level of free dark-sky accessibility to space (step outside at night, buy binoculars, a Celestron, or LSST, and just look up) would be crippling for any nation.
The tax burden required to move Earth's level of free dark-sky accessibility to space (step outside at night, buy binoculars, a Celestron, or LSST, and just look up) would be crippling for any nation.
But think of the return on the investment of cool.
Observations are being ruined now. Those cheap space telescopes will be available when ecactly?
Is there even any project in the works besides JWT?
Projects like these take a lot of time.
Improve observation data post processing. Lasers are used as artificial stars [1] to subtract atmospheric distortion, use stacking [2] to remove StarLink tracks. Those observations aren't being "ruined", they simply have some noise to remove.
Long term, we should be lifting observatories (both optical and RF) into orbit, Lagrange points, or the Moon. Observing from the ground sucks comparatively, and there's a lot of space out there.
[1] https://en.wikipedia.org/wiki/Laser_guide_star
[2] https://www.skyandtelescope.com/astronomy-blogs/imaging-foun... (Satellites, Begone! Remove Trails from Your Astrophotography)
Long term, we should be lifting observatories (both optical and RF) into orbit, Lagrange points, or the Moon. Observing from the ground sucks comparatively, and there's a lot of space out there.
[1] https://en.wikipedia.org/wiki/Laser_guide_star
[2] https://www.skyandtelescope.com/astronomy-blogs/imaging-foun... (Satellites, Begone! Remove Trails from Your Astrophotography)
That might work for imaging, but what's your fix for spectroscopy?
Yes WFIRST[0] is currently in the works.
JPLRMA[1] is investigating low cost mirror for space observation although they are primarily focused on the outer planets of our solar system.
[0]https://wfirst.gsfc.nasa.gov/ [1]https://www.nap.edu/resource/13117/App G 19_Enceladus-RMA.pdf
JPLRMA[1] is investigating low cost mirror for space observation although they are primarily focused on the outer planets of our solar system.
[0]https://wfirst.gsfc.nasa.gov/ [1]https://www.nap.edu/resource/13117/App G 19_Enceladus-RMA.pdf
So I'm confused, because according to https://caseyhandmer.wordpress.com/2019/11/02/starlink-is-a-...
"Based on the Starlink website, that all satellites will be deployed below 600km. In this case, satellites may be visible during twilight but not after nightfall, greatly reducing the potential impact to astronomy."
Can anybody verify this?
"Based on the Starlink website, that all satellites will be deployed below 600km. In this case, satellites may be visible during twilight but not after nightfall, greatly reducing the potential impact to astronomy."
Can anybody verify this?
It's the physics of the arrangement of satellite, sun, and Earth. The satellites are only visible due to reflected sunlight, and they're flying quite low for satellites, i.e. near to Earth. The nearer an orbital object is to Earth, the larger percentage of the arc of its orbit is occluded by the Earth's shadow.
Given their close proximity to Earth, they can reflect sunlight at dawn and dusk (when the sun is shining "along" the surface relative to the observer) but when an observer is in nighttime (i.e. within Earth's shadow), Earth blocks the path of light to reflect off the satellites and they won't shine. Hypothetically, they could still pass in front of distant objects and occlude them, but I'm assuming based on the way the problem is described that flooding a telescope with reflected light is more of a problem than occluding a distant object for a few moments.
Given their close proximity to Earth, they can reflect sunlight at dawn and dusk (when the sun is shining "along" the surface relative to the observer) but when an observer is in nighttime (i.e. within Earth's shadow), Earth blocks the path of light to reflect off the satellites and they won't shine. Hypothetically, they could still pass in front of distant objects and occlude them, but I'm assuming based on the way the problem is described that flooding a telescope with reflected light is more of a problem than occluding a distant object for a few moments.
[deleted]
Laws to protect astronomy? Really? Talk about the strong needs of the few outweighing the weak-moderate needs of the many. If I was an astronomer I would be pissed, but let’s have some perspective here: vastly more people are going to be helped by this than hurt.
Moreover, this sky pollution has already happened with light and eventually will become a problem with satellites. There’s just no stopping it and we should recognize that things change, sometimes for better or for worse. But mostly, better for some and worse for others.
Moreover, this sky pollution has already happened with light and eventually will become a problem with satellites. There’s just no stopping it and we should recognize that things change, sometimes for better or for worse. But mostly, better for some and worse for others.
I worry about the precedents being created. There is little in the way of other companies or governments adding more to Earth’s orbit. Eventually there could be enough objects there that one single incident could cause a chain reaction and blanket Earth on debris making launches dangerous or impossible.
Note that although this sort of event would make LEO unusable, which isn't good - it would _not_ actually do several things commonly portrayed in fiction alongside that.
It wouldn't prevent leaving the Earth, passing through LEO after a Kessler event wouldn't be unreasonably dangerous because you're not there for long. This means you could still go to the Moon, or to Mars, if you've got any reason to do so.
It wouldn't prevent us putting satellites into higher orbits, in particular the GEO communications satellites are so ludicrously much further up than LEO that to say Kessler would inhibit GEO is as if you imagined that a blocked storm drain in your street might lead to Mount Everest being covered by the rising water.
It wouldn't prevent leaving the Earth, passing through LEO after a Kessler event wouldn't be unreasonably dangerous because you're not there for long. This means you could still go to the Moon, or to Mars, if you've got any reason to do so.
It wouldn't prevent us putting satellites into higher orbits, in particular the GEO communications satellites are so ludicrously much further up than LEO that to say Kessler would inhibit GEO is as if you imagined that a blocked storm drain in your street might lead to Mount Everest being covered by the rising water.
Fiction may have imagined doomsday scenarios, but it has also envisioned the solution to them
https://en.wikipedia.org/wiki/Planetes
https://en.wikipedia.org/wiki/Planetes
All the SpaceX satellites are in LEO, low enough that even in the absolute worst case scenario (which, FWIW, is not realistic), they will all de-orbit in a couple years.
That is technically true for this batch of satellites. However at the next shell out that they're planning on using (1150km) it can take a really long time for an orbit to decay (decades or centuries depending on the size of the thing). There's still radioactive crap in orbit from Soviet satellites that were orbiting at 900km more than 40 years ago.
All of these automatically fly themselves to destruction. So we are really only talking about a few defect ones.
Once we are launch 1000s of satellites we are defiantly going to have servicing satellites out there. Refueling, orbital maneuvers and so on.
Even in the worst case, decades is still not that crazy. The locations are known and can be avoid.
This is a problem, but really not any kind of gigantic issue that should stop progress.
Once we are launch 1000s of satellites we are defiantly going to have servicing satellites out there. Refueling, orbital maneuvers and so on.
Even in the worst case, decades is still not that crazy. The locations are known and can be avoid.
This is a problem, but really not any kind of gigantic issue that should stop progress.
and they will be replaced after that
This has a name!
https://en.wikipedia.org/wiki/Kessler_syndrome
https://en.wikipedia.org/wiki/Kessler_syndrome
Light pollution is probably a bigger problem, except on the tallest mountains, or ironically, in orbit.
These astronomers seem to be obsessed with one guy, when there are way more than just his satellites up there. It makes me think it's more of a lobbying effort than a clear-sky thing.
These astronomers seem to be obsessed with one guy, when there are way more than just his satellites up there. It makes me think it's more of a lobbying effort than a clear-sky thing.
The noise looks very predictable, should be super simple to filter out
Super simple == many people-centuries sapped from funding-strapped research.
Furthermore, astronomy is just entering a paradigm where the entire sky can be imaged multiple times per night with great optical depth. Transients are going to be the next frontier, and that is precisely what these constellations will create. A few lost satellites with improperly-documented orbits can fake optical transients.
Furthermore, radio astronomers have moved to the outback of Australia to get away from rare radio transients. A zoo of satellites is precisely something they don't need.
Furthermore, astronomy is just entering a paradigm where the entire sky can be imaged multiple times per night with great optical depth. Transients are going to be the next frontier, and that is precisely what these constellations will create. A few lost satellites with improperly-documented orbits can fake optical transients.
Furthermore, radio astronomers have moved to the outback of Australia to get away from rare radio transients. A zoo of satellites is precisely something they don't need.
Essentially. It's an inconvenience for individual astronomers who time-share on telescopes that sometimes a blob of Starlink passes and sometimes it doesn't. If the full constellation is launched and disbursed, everyone will be inconvenienced about equally, so the fairness issue goes away. And the degraded signal can be cleaned up with digital processing factoring in knowledge of the Starlink node positions.
Once we have that man things in space we will have the launch capacity to launch gigantic/multi satellite space overvaluation platform for gravitational and 'normal' astronomy. Astronmy will benefit from this overall.
And what the alternative, for the rest of time not using this capability?
I understand that they are sad, but since this doesn't even effect the majority of astronomers, I really think this is kind of a non-issue.
And what the alternative, for the rest of time not using this capability?
I understand that they are sad, but since this doesn't even effect the majority of astronomers, I really think this is kind of a non-issue.
It will affect the majority of earth-based astronomers -- science these days comes from the concordance of experiments.
I'm extremely pro-space research, but if I had to weigh the benefits of some astronomers observations being obscured sometimes versus getting hundreds of millions of people onto the internet, I think the choice is pretty clear.
there are other ways to deliver internet
there are other ways to do astronomy
from Earth there's only one way: telescopes
Starlink hasn't rendered telescopes inoperative, nor will it. They still work for 99+% of viewing time, and the satellites in question are invisible on most of the radiation band telescopes can operate on.
This is a tempest in a teapot complaint. Ground-based telescopes already need to account for the existence of satellites, airplanes, birds, the ISS, etc. The Starlink constellation is just increasing the number of the things; it's not changing the nature of the challenge.
Or would you recommend we ban microwave ovens because they deliver noise near the radio spectra we use for Internet communication?
This is a tempest in a teapot complaint. Ground-based telescopes already need to account for the existence of satellites, airplanes, birds, the ISS, etc. The Starlink constellation is just increasing the number of the things; it's not changing the nature of the challenge.
Or would you recommend we ban microwave ovens because they deliver noise near the radio spectra we use for Internet communication?
Banning microwave ovens (and RF transmission in general) is precisely what is done near radio-astronomy sites (see Green Bank, the SKA, etc.)
... but not throughout the whole town housing the telescope.
Including the town housing the telescope: https://greenbankobservatory.org/the-land-where-the-internet...
Do you propose to pass laws to turn the world into Green Bank, W.Va?
Because I, for one, kinda enjoy being able to have the conversation we're having right now.
Because I, for one, kinda enjoy being able to have the conversation we're having right now.
We are having this conversation now without significantly impeding the work of astronomers.
Is there anything that trumps the needs of astronomers in your book? If we could go to 100% carbon free energy, but severely reduce ground based astronomical observations, would you be against that?
Astronomers are way behind on this -- it has never been a problem before -- but launching a huge constellation of satellites before considering the potentially irreversible impact on a branch of science seems unwise to me.
Global internet sounds awesome, and has undeniable benefit to humankind. Uncoordinated launches of large constellations will have some detriment to humankind. The thing I'd like to see is a clear-eyed assessment of the impacts and mitigation strategies before there are billions more in sunk costs deployed in launching these constellations. Once they're up, they're up, and large companies will lose huge if the constellations have to come back down.
Motorola's bankruptcy came from insufficient monetization of Iridium. SpaceX will be in the same boat, if they aren't already.
I'm an experimental physicist, not an astronomer. Limiting systematic uncertainty is what I do all day. When I see these constellations, what I see is a zoo of uncontrolled systematics and a shrinking opportunity to address them before they become permanent.
As someone who looks at the stars, I want generations in the future to look at the stars and have their imaginations captured by distant pinpricks of burning hydrogen, not a visual screen of our own construction. Our children's understanding of our place in the universe may depend upon it.
Global internet sounds awesome, and has undeniable benefit to humankind. Uncoordinated launches of large constellations will have some detriment to humankind. The thing I'd like to see is a clear-eyed assessment of the impacts and mitigation strategies before there are billions more in sunk costs deployed in launching these constellations. Once they're up, they're up, and large companies will lose huge if the constellations have to come back down.
Motorola's bankruptcy came from insufficient monetization of Iridium. SpaceX will be in the same boat, if they aren't already.
I'm an experimental physicist, not an astronomer. Limiting systematic uncertainty is what I do all day. When I see these constellations, what I see is a zoo of uncontrolled systematics and a shrinking opportunity to address them before they become permanent.
As someone who looks at the stars, I want generations in the future to look at the stars and have their imaginations captured by distant pinpricks of burning hydrogen, not a visual screen of our own construction. Our children's understanding of our place in the universe may depend upon it.
The article you linked to specifcally noted not only microwaves but also cellular towers and wifi were banned in Green Bank. I have no doubt that banning microwaves, cell towers, and wifi globally would make radio astronomy easier.
... but we also wouldn't be having this conversation, as I lack a land-line connection to the Internet right now.
... but we also wouldn't be having this conversation, as I lack a land-line connection to the Internet right now.
Could something like Starship carry a large mirror?
Or could it ever be feasible to manufacture a large mirror on the moon, if a large enough one can't be flown?
Or could it ever be feasible to manufacture a large mirror on the moon, if a large enough one can't be flown?
Starlink is the way SpaceX is funding exploration to Mars. Please stop complaining about your minor inconvenience. Someone in the government might listen and cause needless regulation halting space exploration progress.
the view of the night sky is about to be destroyed by companies
Not really. The satellites will be too small to see unaided in general, and their proximity to Earth means that outside of twilight hours, they're generally invisible.
(Also, "destroyed" is a matter of perspective. I think it'd look kind of cool if every twilight you could look up and see a web of satellites drifting quietly overhead ;) ).
(Also, "destroyed" is a matter of perspective. I think it'd look kind of cool if every twilight you could look up and see a web of satellites drifting quietly overhead ;) ).
What SpaceX should do is equip every satellite with a camera and lens specialized for astrophotography pointed away from Earth to the sky. Then give every one of them a unique ip address and interface that astronomers and anyone else can connect to and take pictures and videos. Some of them could even get equipped with bigger telescopes.
A ton of cheap low-quality instruments does not always equal a single expensive instrument. For optical astronomy the only currently reliable way to get higher resolution is to get larger mirrors. And we are not even mentioning the importance of a well calibrated cooled sensor.
The telescope in the OP whose observations were interrupted has a 4m primary mirror. Hubble has a 2.4m primary mirror.
The optical corrector lens -- just the corrector lens alone -- that is part of the camera instrument of OP has a diameter of 1m, with a mass of about 200kg. (https://www.darkenergysurvey.org/the-des-project/instrument/). The entire Starlink satellite mass is 227kg.
I don't think SpaceX is going to be putting instruments of this class on its satellites.
The optical corrector lens -- just the corrector lens alone -- that is part of the camera instrument of OP has a diameter of 1m, with a mass of about 200kg. (https://www.darkenergysurvey.org/the-des-project/instrument/). The entire Starlink satellite mass is 227kg.
I don't think SpaceX is going to be putting instruments of this class on its satellites.
That is not what I am suggesting either. Smaller telescopes and cameras but on every satellite which can then be combined computationally as well. Tons of possibilities. Of course, like I said, they could also equip some of them with more powerful and larger hardware. But the smaller ones would already provide lots of capabilities for very little extra cost relatively.
OK, but that's not addressing the problem raised in the OP.
Dedicated CubeSats have largely filled the smallsat niche. I would expect the Starlink mass has been carefully optimized already.
There are interesting mission concepts (telescope + star shade; NEO detection [1]) that are in the works with dedicated CubeSat constellations, but yoking them to another spacecraft bus with its own constraints doesn't sound likely to succeed.
[1] https://www.aanda.org/articles/aa/full_html/2017/07/aa29809-...
Dedicated CubeSats have largely filled the smallsat niche. I would expect the Starlink mass has been carefully optimized already.
There are interesting mission concepts (telescope + star shade; NEO detection [1]) that are in the works with dedicated CubeSat constellations, but yoking them to another spacecraft bus with its own constraints doesn't sound likely to succeed.
[1] https://www.aanda.org/articles/aa/full_html/2017/07/aa29809-...
As this comment implies, the worst case impact to astronomy is only going to be about 30 to 60 minutes lost per night right after dusk and before dawn. There will still be uninterrupted viewing time in the middle of the night because the satellites will be in Earth's shadow and not visible at all.
Personally, I think the benefit of truly global broadband internet from space is worth the cost of an hour of observing time per night. Even in the worst case, ground based astronomy can still happen. "Despair" is not warranted.
On a related note, I made a website to predict when the Starlink satellites will be visible for you. They look pretty cool if you can catch them, but viewing opportunities are limited because of that limited time window before they enter Earth's shadow. https://james.darpinian.com/satellites/?special=starlink-201...