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SATCON1 Report on Impact of Satellite Constellations on Astronomy
- ISL 6y agoThe document has an executive summary and clear images denoting the impact of these satellites on humanity's view of the stars. It does a great job of highlighting the collision between high-sensitivity wide-field imaging of both deep fields and transients with the nascent satellite constellations. Direct link to the PDF: https://noirlab.edu/public/media/archives/techdocs/pdf/techdoc003.pdf https://noirlab.edu/public/media/archives/techdocs/pdf/techd... Astronomers have been working for decades toward the Vera Rudin Observatory (nee LSST). It has been the big thing on the horizon for my entire career as a professional scientist. It sees first light in 2021. Images like that seen on page 7 of the PDF will be what they see. https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory https://en.wikipedia.org/wiki/Vera_C._Rubin_Observatory
- nsilvestri 6y agoLSST/Vera is probably the project most impacted by these satellites. Per my contacts, smaller scopes like LBT/Keck/MMT aren't as drastically affected yet. But if we start approaching 100k+ satellites, even they will be having some major issues to deal with.
- ISL 6y agoThe real tragedy, from a scientific standpoint in the optical, is that we're entering a new world of wide-field and sensitive time-domain astronomy due to huge improvements in computing power and sensors at the same time that humanity is about to generate thousands of bright transients. The only practical approach I can think of for combating the constellations is distributed arrays of wide-field transient-hunters. As long as the transient is common-mode across telescopes, then it is real. If there are three LSSTs, and not too many constellation-satellites, that might work. I just noted, in passing, that the term for the satellite arrays appears to be "constellation"; that is a bummer in this context.
- spenczar5 6y agoThis is an area of very active work by the Rubin/LSST team. Some documents that might be of interest, pretty hot off the press: - "Mitigation of LEO Satellite Brightness and Trail Effects on the Rubin Observatory LSST" https://arxiv.org/abs/2006.12417 https://arxiv.org/abs/2006.12417 - "Mitigation of Satellite Tracks in LSST Data Processing" - https://aas.org/sites/default/files/2020-07/MitigationWG_Present5_bySaunders.pdf https://aas.org/sites/default/files/2020-07/MitigationWG_Pre... There are some good techniques available, and the very smartest experts on image processing are working on this task, so I think we'll manage.
- nsilvestri 6y agocorrection to above (can't edit anymore): I meant smaller scopes, as in "smaller field of view" or immediate area of concern, not smaller in aperture
- hinkley 6y agoI thought this was going to be about collisions between satellites from two constellations. As someone loudly lamented a long time ago: please stop using the word “impact” as a substitute for figuring out effect/affect.
- reaperducer 6y agoAs someone loudly lamented a long time ago: please stop using the word “impact” as a substitute for figuring out effect/affect. "A long time ago" might be the 1700's, because it's been in use that way for several hundred years. So don't hold your breath.
- hinkley 6y agoI’m this case it was within this century, which is quickly becoming a time before some participants here had learned to read. The older you get, the more the line between “long enough” and “a long time ago” begins to blur.
- ziddoap 6y agoThe title of the article is unambiguously not talking about collisions between satellites: "Impact of Satellite Constellations on Optical Astronomy[...]". Many words have multiple definitions which require you to use context clues to figure out which definition applies.
- hinkley 6y agoExcept our title is SATCON1 Report on Impact of Satellite Constellations on Astronomy and orbital debris does have serious consequences for astronomy. So I'm still going to say: Phrasing!
- dvaun 6y agoThe technical report is quite large (105MB). Here is a compressed version (6MB): https://www.dvaun.com/files/satcon1-compressed.pdf https://www.dvaun.com/files/satcon1-compressed.pdf I'm a bit confused by why they included such high-res images in the PDF in the first place. Edit: After taking a look at the original I see that they embedded some of the files they created with Photoshop and After Effects directly into the document. They forgot to resize the images, hence the huge object streams in the file.
- ISL 6y agoAgreed that they could have downsampled it for expedience, though the point is that systems spanning the gamut from the human eyeball to cryogenically-cooled 3.2 gigapixel imaging sensors are impacted by these constellations. Those sensors are 3.2 gigapixels at 16-bit depth, so each image alone is 6.4 gigabytes. 108 MB seems small by comparison; that is only one telescope out of all the sky-imaging (optical and radio) systems on the planet.
- dvaun 6y agoI appreciate the sense of scale that your explanation brings. I understand that. The size of the PDF is not a symbol for the work being done here, though. Reducing it makes it cheaper to distribute and easier for viewers to read their findings. That is my reasoning for putting up another version.
- mlindner 6y agoHuman eyeball is not impacted. These satellites are below the limits of human observation generally, even in dark skies.
- tekstar 6y agoI'm generally a technologist however I am completely appalled at a private company getting the right to significantly impact humanity's view of the night sky, the original source of wonder.
- avmich 6y agoYes, this is a kind of Wild West situation. We should figure out the best way out, ideally with all interested parties getting something good.
- leeoniya 6y agoexcept you as an individual could opt out of the original Wild West; this one, not so much. perhaps it's exactly like the Wild West from the viewpoint of Native Americans: we're taking your skys.
- avmich 6y agoYes, that's very unfortunate. I hesitate, however, concluding that we should ban satellite constellations on these grounds. Do you think that would be a good approach?
- tekstar 6y agoYes, unless they are invisible in the sky. Put a barrier in place to force innovation.
- avmich 6y agoAnything in the sky is something which at least obstructs the view. If we have too many even black body satellites - which have zero reflection or emission in interesting spectral parts - we're still can't see through them. If we have too many of them, we still have a problem. So - theoretically - it's a choice between space flights and astronomy. Maybe there can be a more optimal solution than what we have today.
- avmich 6y agoDense satellite groups are a real game-changer in how we observe the sky from the surface of Earth. We're at the choosing point right now, what's better for us - a good uniform global communications or the pristine sky. The sky was always the norm; but it ceases to be so. In order to have some compensation to astronomical society - that is, the whole population of Earth, as even looking to bight sky is getting be different - it would be good for SpaceX to create a program of high-orbit astronomical observatories. Working together with Earth astronomers, the company can participate in changes to observation possibilities in a way which has some upside as well, in addition to anticipated degradation. Hubble space telescope was launched some 30 years ago; an observatory of similar class or better can be significantly more affordable today, there can be several - or many - of them and that could be a worthy trade-off to the degradation of Earth-visible sky. I'm sure astronomical society would be very interested in participating and helping with building such a group of space observatories.
- pueblito 6y agoOf course astronomical societies would be interested in someone gifting them some wildly expensive equipment.
- avmich 6y agoTo get better - much better sometimes - view of the sky, yes. And not only gifting - working together with world-class practical space engineers on building space observatories with potential benefits not expected before this issue becoming significant. I'm serious here - seeing Elon Musk traditions, it would be not ridiculous to test such an approach.
- shadowgovt 6y agoI think the key part here is "how we observe the sky from the surface of Earth." The same economics that is putting cheap satellites in orbit should be usable to put cheap telescopes in orbit. What is needed to do that? Because I'm imagining an array telescope with the diameter of an Earth orbit.
- avmich 6y ago
- tectonic 6y agoWe've been covering this issue frequently in Orbital Index (https://orbitalindex.com https://orbitalindex.com). With around 10,000 stars visible with the naked eye, there will be significantly more satellites than stars, even from a single constellation like Starlink or Project Kuiper. Granted, most of those satellites won't be visible at any given time, but I do worry about the ability of LSST and other wide-field observatories to do their (very expensive & important) jobs—one of those jobs is spotting near Earth asteroids with a collision potential. Here's a recording of the recent 'Impacts of Satellite Constellations on Optical Astronomy' webinar that discussed this and had someone from SpaceX: https://www.youtube.com/watch?v=LaR6v0p6pB4 https://www.youtube.com/watch?v=LaR6v0p6pB4
- leoedin 6y ago> one of those jobs is spotting near Earth asteroids with a collision potential What actually happens if they spot an asteroid with collision potential? Is there anything we can do about it?
- 46Bit 6y agoIf it's a week away and massive? Not much. If it's years or decades away, we could try.
- shadowgovt 6y agoIf only there were some way to lift a bunch of cheap kill vehicles into orbit that could be used for both detection and interdiction of incoming rocks with little notice... (I know, it's not exactly that simple. But still.... ;) )
- ceejayoz 6y agoAny rock you can tackle on little notice is a rock that wouldn't have done much anyways. Anything with the size to have significant impact on Earth is gonna require years of lead time to tackle; you'd need to start changing its orbit well in advance.
- jankotek 6y agoCheap rockets will make space telescopes way more accessible. Ground survey telescopes have serious limitations. So for science this could be a positive thing. I am more worried about monopolies and accessibility of this new internet. If it ruins sky for everyone, but only a few can afford it, that would be a terrible deal.
- Rebelgecko 6y ago>Cheap rockets will make space telescopes way more accessible. I'm not convinced that's true. If you look at past space telescopes, launch costs are not a large part of the budget. Even if SpaceX gave everyone free launches as a goodwill measure, you'd only make space telescopes maybe 2-5% cheaper. There's very real challenges that space based telescopes have that Earth based ones don't (how do you make a cryocooler that doesn't vibrate your optics? How do you make a machine that can run for years without maintenance? How do you get precise enough positioning to interferometry?). My understanding is that due to adaptive optics, being ground based isn't much of a problem for visual telescopes. And for large radio telescope arrays, I don't see how it's possible at all to move to space
- mlindner 6y ago> If you look at past space telescopes, launch costs are not a large part of the budget. Satellites are built to narrow margin to reduce weight because of the weight restrictions on satellites. Right now we have reusable rockets but the rockets aren't any bigger so while the cost of launch has come down the volume/mass that can be launched in one go has not gone up. If laser interferometry gets better then large telescopes can be launched as constellations. Larger reusable rockets are also being worked on. When that happens they can care less about mass margin and make cheaper lower margin telescopes. Telescopes are also generally built as a one-off which also increases cost. I hope the technology for telescope constellations will improve.
- Rebelgecko 6y agoEven if there's room for additional weight, that doesn't help with the other aspects of SWAP. Size: There's still a finite fairing size. Even the biggest upcoming rockets can't fit a 30m mirror in one piece. Weight: say you want to put something like ALMA in space, which weighs over ten million pounds. Even with platforms like starship,you're not going to be able to do that in one go. Maybe one launch for each of the 66 antennas,but even that is iffy. Power: Hubble's power consumption is around 2Kw. Using ALMA as an example again, each individual antenna uses about 10x more electricity than that on average. More electricity means you need RTGs or nuclear reactors (not politically popular, complicates thermal regulation, potential for spreading radioactive waste across orbit and earth a la RORSAT), or massive arrays of solar panels. Massive solar panels means even more weight and space required For interferometry, knowing your location to the nanometer is just the first of many challenges. You have to station keep across the constellation (tricky to do continuously while you're in orbit!), it becomes even more important to minimize vibrations, etc
- ideals 6y agoWhat are going to be the cultural effects of having a constant stream of satellites wizzing around the night sky? I've sat here for a few minutes thinking selfishly about never being able to experience Alaska wilderness on a clear night. Or late night stroll on a beach looking up, etc, etc forever about all kinds of personal moments that will never be the same. However there's billions of people who have no idea what Starlink or Kuiper are that are going to find out the hard way when they no longer have that same night sky either. I hadn't really thought about it much before because it was always framed as an astronomy problem, but it's really a whole Earth's peoples problem.
- ideals 6y agoFollow on comment, what are indigenous tribes who aren't part of our connected world going to interpret this change as? I'm thinking about groups of people like the Sentinelese.
- mlindner 6y agoThe indigenous tribes won't be able to see them so it has zero effect on them.
- mlindner 6y agoPeople appear to be downvoting my other comment so much that I can't even edit it so reposting again. Indigenous tribes won't have an issue with it as they don't have superhuman eyes to see 7th magnitude objects in the night sky. The satellites are not generally visible to the naked eye after changes SpaceX has made to the operations of the satellites and physical modifications to the satellites themselves. https://www.spacex.com/updates/starlink-update-04-28-2020/ https://www.spacex.com/updates/starlink-update-04-28-2020/
- mlindner 6y ago> I've sat here for a few minutes thinking selfishly about never being able to experience Alaska wilderness on a clear night. Or late night stroll on a beach looking up, etc, etc forever about all kinds of personal moments that will never be the same. You can't see them on a clear night. They're not a problem for human observation, only telescopes.
- jacquesm 6y agoIt's littering on the largest scale imaginable.
- kome 6y agoPeople, let's get real for a minute. Why are we allowing a private company to ruin the night sky for everybody, and by everybody, I mean literally everybody on this planet? This should be discussed in a democratic and international way. It’s nor going to be easy, but it is necessary. I can't believe future generations won't see a pristine night sky anymore...
- deleted 6y ago[deleted]
- mlindner 6y ago> Why are we allowing a private company to ruin the night sky for everybody, and by everybody, I mean literally everybody on this planet? They're not being ruined for everybody. There's so many misinformed comments in this thread. These satellites aren't visible to the human eye generally.
- kome 6y ago"generally" is the key: not long ago in northern Italy everybody was freaking out because of this: https://cdn.dmove.it/images/18547/StarMain.jpg https://cdn.dmove.it/images/18547/StarMain.jpg Those are the ones by Starlinks. That's not acceptable. They are so invisible to the naked eye, that the weather website gives you the exact time and date of their passage in the sky: http://www.meteoweb.eu/2020/05/passaggio-satelliti-starlink-14/1433303/ http://www.meteoweb.eu/2020/05/passaggio-satelliti-starlink-... (in Italian)
- mlindner 6y ago1. That is only in the roughly week following launch, which doesn't harm anyone. 2. They changed operations immediately after launch and so you generally can't see this anymore. They are indeed invisible after launch. Your article is from March, before changes were made. Try to find anyone taking pictures of them in that chain of pearls form in the last few months.
- mchusma 6y agoThis NIMOP ("Not In My Orbital Plane") movement is very concerning and I feel the need to speak out against the dangers of this "luddite movement" type thinking. First, of course its good for companies to reduce the negative externalities of things in space (paint, shades, etc). I think there is near universal agreement here, including from SpaceX. However, there is no way to become a space faring civilization without putting lots of things in space, period. I want to see 1,000,000x more objects in space, including much larger ones. If we truly become space faring, we have the matter and resources to have a quadrillion humans living in comfort (likely in large rotating space habitats like"O Neil Cylinders"). This is the kind of dream we could have, imagine over 100,000x the humans, artists, friendship, science, and love. We can simultaneously make earth an ecological paradise, with most of the planet reserved for nature. This "anti-satellite" movement seems to generally have 4 kinds of attacks against the satellites: 1) The satellites "impede my rights to view the sky". The implication is that anyone who attempts to build in their "view to infinity" violates their rights. This seems like an extremely presumptuous statement, like they own trillions of miles. This also doesn't match the current legal framework of any country (nobody needs your permission to fly over your house in aircraft or space). 2) The usecase of these satellites is bad because they are "like cell towers". Getting low cost internet access for the planet is IMO an extremely good thing, one of the best things for the poor. 3) The satellites will kill astronomy. This is absurd, we will have much better astronomy if we are a space fairing species with cheap space access and many things/expertise in space and giant telescopes outside our atmosphere. It may kill amateur astronomy from earth eventually, but I just don't think that as society a relatively fringe hobby should stop the progress of humanity. Many hobbies have been killed over time. I personally think this will inspire more people to look to space, and have the opposite effect. 4) We should not put things into space, and we should look to reduce our impact on the universe. This also manifests itself in those that want to see population reduction on Earth. I believe consciousness is better than lifeless rock. I say this as a human and a parent who has brought consciousness into the world. Lets upgrade our dreams, take to the stars, and make the universe a more interesting place.
- jacquesm 6y agoRight. The problem is not that it is 'in my orbital plane', the problem is that it is in everybody's orbital plane whether or not they - or their government - has a say in the matter. You can't escape it. There is no backyard where this isn't an issue. This is now presented as a fact we will have to live with and if you are against 10's of thousands of orbital satellites you are now - according to you - immediately against progress. This obviously isn't the case. So, let's stop the clock for a bit until we have a much better idea of what the impact of all this littering will be and whether or not there is something that can be done about it before we end up with a situation that is out of control. SpaceX is not the world, LEO is not US property and whether or not low cost satellite access is such a good thing that we should give up easy access to visible light astronomy is not a given. This has nothing to do with 'taking to the stars', 'making the universe a more interesting place' or 'upgrading our dreams'. It is a simple commercial proposition.
- 4gotunameagain 6y agoWhether you agree or disagree with huge sat constrellations, I think that a matter that clearly impacts the entire world should not be decided by a handful of people from a single country.
- sschueller 6y agoNor a single billionaire. If China or Russia was the one building starlink the reception in the US would be a lot different.