[HN Gopher] How bad are satellite megaconstellations for astronomy?
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How bad are satellite megaconstellations for astronomy?
Author : belter
Score : 40 points
Date : 2024-05-09 20:11 UTC (2 hours ago)
(HTM) web link (www.leonarddavid.com)
(TXT) w3m dump (www.leonarddavid.com)
| tetris11 wrote:
| I know it's a blessing for people who live out in the sticks to
| have internet.... but is that really such a large use-case to
| justify entire fleets of these things?
|
| How hard is it to run km of wire from the nearest town?
|
| To me, these were built for the sole purpose of surveillance, and
| internet is an afterthought.
|
| Edit: yes yes it's expensive, but the easiest solution the world
| came up with was for some guy to invest billions in a satellite
| program?
| philomath_mn wrote:
| > How hard is it to run km of wire from the nearest town?
|
| Very hard, especially when the towns are much more dispersed
| than a km apart.
| LeoPanthera wrote:
| > How hard is it to run km of wire from the nearest town?
|
| If it's not hard, why hasn't it happened already?
| oh_my_goodness wrote:
| To be fair, people are already using wire.
| digging wrote:
| (in the US) It may be hard for a new company but easy for
| existing telecom giants. But existing telecom giants don't
| give a shit about national internet infrastructure quality,
| so if connecting rural customers simply _appears less_
| profitable* than focusing on current operations[1], they won
| 't do it.
|
| [1] Current operations include the obviously profitable "send
| monthly marketing materials via mail, email, and live
| salespersons to homes who canceled your services the day they
| had an alternative," among other idiotic practices.
| FredPret wrote:
| Super hard.
|
| You have to dig a trench or span the wire. Either way you
| need to clear it with numerous property owners over a vast
| distance, get approval from dozens of authorities along the
| way, coordinate work crews, and then do maintenance on the
| whole thing for decades.
|
| And then you discover that the wire used 50 years ago
| contained lead and we don't like that anymore, so now you
| have to pay for massive lawsuits (look up AT&T & Verizon) and
| rip up all that wire. More coordinating work crews and
| property owners!
|
| And then they invent a new kind of wire and you have to do it
| all again.
|
| Launching 1000's of satellites isn't easy but I can see
| wanting to do that rather than wire up the whole planet.
| ajford wrote:
| Because telecoms keep pocketing the money instead of actually
| building out broadband. https://www.huffpost.com/entry/the-
| book-of-broken-promis_b_5...
| ericd wrote:
| Yeah, I'm not sure why trenching is so expensive, I think PG&E
| was quoting something silly like millions per kilometer. I'm
| planning on doing like a tenth of a kilometer in a day with a
| $400 trencher rental pretty soon. I'm sure it's not apples to
| apples, but the delta there seems pretty baffling.
|
| For me, the biggest hang up has just been that I'm required by
| the state to get it inspected before I put in the conduit, and
| that ramps up the complexity of coordinating things quite a
| bit, because I'd rather not leave it open too long. If they
| have to deal with a bunch of bureaucratic coordination, then I
| could see the actual labor becoming a relatively tiny part of
| the difficulty/cost.
| iwontberude wrote:
| It might cost money to figure out where to prioritize
| resources
| ericd wrote:
| Yeah, but if the planning that's meant to make things
| efficient is using up almost all the money, seems like
| maybe we need to rethink how we're doing things.
| oh_my_goodness wrote:
| Hard enough that some people are putting up satellites instead.
|
| EDIT: Say there's some way to put in fiber at $10k per km. Even
| then, ten million users at 1km per user makes $100 billion.
| bmitc wrote:
| To me, these are capitalistic solutions looking for problems.
| It's the whole startup mentality. Let's just throw a bunch of
| shit in space and see if it ends up being useful for
| anything. This idea of connecting the world is as false as
| the other hundred millions times that's been sold.
| oh_my_goodness wrote:
| Yeah, fair. Just because stuff is expensive doesn't mean
| it's worth anything.
| FredPret wrote:
| If you paid attention, "this time" and also the "other
| hundred million times" are true, not false.
|
| We're massively more connected than ever before.
|
| Homeless people in the third world have phones now. They
| should be able to get on the internet too.
| ggreer wrote:
| Useful for anything? Starlink useful to its 2.7 million
| subscribers. And it's already profitable. As of last year,
| SpaceX makes more in subscription fees than it costs to
| build and launch the satellites. The economics will only
| become more favorable when SpaceX improves their launch
| capabilities with Starship.
| Starlevel004 wrote:
| As far as I'm concerned, those people should either live in
| civilisation like the rest of us or live out there and get zero
| utilities at all.
| a2l3aQ wrote:
| Not a great point of view when the cities don't grow all that
| much food.
| Starlevel004 wrote:
| Neither do most ruraloids and especially not the ones
| actually paying for the satellites.
| downWidOutaFite wrote:
| ISPs were paid billions to do this in the US and then stole the
| money and didn't do it thanks to regulatory capture.
| shadowgovt wrote:
| In many cases, the issue isn't cost to run but cost to
| maintain.
|
| Consider South Africa, where the largest threat to installation
| deployment is inability to police the entire deployment coupled
| with massive wealth inequality... People just dig the cables
| out of the ground for the copper. Cellular radio has
| ameliorated the issue some (harder to steal the repeater
| antenna out of the back yard of a shotgun-owning resident), but
| Internet can still be a challenge.
| pfdietz wrote:
| It's getting to the point it's not even worthwhile to run power
| lines to remote locations.
| delichon wrote:
| On the one hand the constellations are doing considerable damage
| to surface based astronomy. On the other hand they are funding an
| enormously lower cost of access to orbit and beyond for astronomy
| up in the sky.
| marcosdumay wrote:
| Yes, the future of astronomy is in space.
|
| If the satellites don't disrupt it, light pollution will
| anyway, or best case, it will be disrupted by atmospheric
| pollution.
|
| There's no lack of clear skies in space.
| DiogenesKynikos wrote:
| The future of astronomy is both on the ground and in space.
|
| There are so many things that you can only conceivably do
| from the ground. You can build vastly larger telescopes on
| the ground, you can install far heavier instruments (like
| cameras and spectrographs) on them, you can upgrade and
| repair components much more easily. You can build massive
| arrays of radio telescopes. You get the point.
|
| There are some things you can only do from space, or that are
| better in space, but saying that everything will be done in
| space is like saying we only need laptops and don't need
| datacenters. You need both.
| mercutio2 wrote:
| Are there really a lot of ground based telescope components
| larger than Starship's fairing?
|
| I'm just not seeing the argument for there being any
| telescope function that wouldn't be better done in orbit,
| at Starship payload prices.
| Retric wrote:
| Yes, though I guess it depends on what you mean by lots:
| https://en.wikipedia.org/wiki/List_of_largest_optical_ref
| lec.... Critically the 30+m monsters under construction
| have only recently become feasible on the Earh let alone
| in space, and much smaller instruments still provide
| significant value today.
|
| There's a much longer list of large radio based
| telescopes which have minimal advantages in space to the
| point where we haven't launched any, and they are also
| negatively impacted by constellations. Also, several
| types of observations don't really benefit from being in
| space. If you want to track killer asteroids space
| doesn't provide much advantage even if you could get
| there for 100$/kg.
|
| IMO the issue here isn't satellites, it's that they can
| harm multi billion dollar investments at zero cost to
| themselves. If you're very clearly causing 10's of
| millions in damages you really should be compensating the
| people affected.
| petsfed wrote:
| I count 13 on wikipedia's list of the largest telescopes.
| There are 3 more currently under construction. The
| evocatively named "Extremely Large Telescope" is
| estimated to cost about $1 billion USD. Who knows how
| much it will _actually_ cost, but for comparison, that 's
| about $400 million less (adjusted for inflation) than the
| _budgeted cost of the_ Webb telescope, which is about 1
| /6 the planned size (and therefore 1/36 the light
| collecting capability).
|
| edit: italicized above. The Webb ended up costing $10
| billion, so the savings could be even larger
| ketralnis wrote:
| A: yeah we're hurting you but if we didn't, B & C would
|
| B: yeah we're hurting you but if we didn't, A & C would
|
| C: yeah we're hurting you but if we didn't, A & B would
|
| I guess it's nobody's fault then
| marcosdumay wrote:
| A lot of people really want A & B. Way more than how many
| want your work.
|
| But well, any one is free to go fight the tide.
| bmitc wrote:
| That needs some citations. The James Webb Telescope's mirror
| is 6.5m in diameter. It took decades and billions of dollars
| of overruns and a prayer to launch and work correctly. There
| is no hope of most hardware repairs.
|
| That mirror size pails in comparison to what can be
| accomplished via ground based observatories for much, much
| cheaper.
|
| And the available modes of operation are completely different
| between space and ground. For example, space observatories
| are using decades old instrumentation techniques, hardware,
| and software. And that's just for starters.
|
| We cannot do astronomy via space exclusively.
|
| For me personally, I never wanted to see something like
| Starlink with my bare eyes, and I have several times. It's
| beyond annoying to me that a company has been able to
| unilaterally pollute the Earth's sky.
| _dain_ wrote:
| _> That needs some citations. The James Webb Telescope 's
| mirror is 6.5m in diameter. It took decades and billions of
| dollars of overruns and a prayer to launch and work
| correctly. There is no hope of most hardware repairs._
|
| Because it had to get launched folded up, because the
| launch vehicles were so space- and mass-constrained. The
| unfolding mechanism was enormously complicated and added to
| much of the cost.
|
| Now we can send up bigger, heavier objects for much less
| money. The 6.5m mirror fits comfortably inside Starship's
| cargo bay, unfolded. JWST is a one-off clockwork
| masterpiece; future space telescopes will come off an
| assembly line. There will be thousands in orbit, pointed at
| every part of the heavens simultaneously.
| lumost wrote:
| Back of the envelope math would suggest that 8-10 JWTs
| could be launched in a single starship flight making for
| an impressive telescope array.
| stevage wrote:
| Did you factor in the fuel to get to where it needs to
| be?
| pfdietz wrote:
| Propellant is very cheap.
| stevage wrote:
| Yeah but it is still mass and volume that might reduce
| available payload?
| rickydroll wrote:
| https://en.wikipedia.org/wiki/Extremely_Large_Telescope
|
| The 39-meter primary mirror has 798 1.4-meter segments,
| each individually adjustable. The scaffolding required to
| hold all the segments is "significant" and must be
| assembled in orbit. We would stick this out next to the
| James Webb at L2, which means we would need the ability
| to travel to L2 to construct this mythical orbital
| extremely large telescope.
|
| With our current technology, we can build ELT on Earth
| for a fraction of the cost of putting it in orbit.
| feoren wrote:
| Why would you assemble it at L2 instead of assembling it
| in LEO and then sending it out on its own?
| _dain_ wrote:
| For one thing, before this decade is out we will have the
| lift capacity to get an ELT-worth of mass to L2. And the
| lack of need to correct for atmospheric distortion would
| simplify the design considerably.
|
| But it's beside the point. Such a singular mega-telescope
| would no longer be the only way to do astronomy in space.
| A world of radically lower launch costs gives more
| possibilities. We could have a fleet of _thousands_ of
| independent small /medium sized space telescopes. That
| way, we wouldn't have to carefully ration imaging time
| between competing astronomy projects anymore. High
| quality data would become cheap and abundant, procured
| on-demand.
| hagbard_c wrote:
| If the promises made for new launch systems like SpaceX'
| Starship (and maybe even, one day, in some unknown future,
| Bezos' Blue Origin manages to launch something larger than
| a phallic pond hopper?) it should become radically less
| expensive to launch larger telescopes into orbit and/or to
| e.g. the moon.
| Almondsetat wrote:
| Exactly my thoughts. Scientists drool at the few telescopes we
| have in orbit. If we could launch more of them for less money
| at the expense of a busier night sky I don't think they would
| want to miss on that
| hehdhdjehehegwv wrote:
| Yes but the issue is how many of those scientist began as
| children using a cheap telescope their parents bought them?
|
| The sky has belong to us all since the dawn of our species
| and has inspired some our most profound art, music, and
| discoveries.
|
| I'm not informed enough to have an opinion, but I do find the
| idea that somehow this is a net win for astronomy is
| misguided.
| stouset wrote:
| Megaconstellations are not a problem for kids looking
| through telescopes. If anything it's _additional_ things to
| wonder at in amazement.
| pfdietz wrote:
| Indeed. The big obstacle for kids is when the entire sky
| is washed out with sodium vapor light and maybe you can
| see Vega.
| throwaway11460 wrote:
| SpaceX single handedly made my whole family excited about
| space exploration. My _mother_ watches every launch and
| landing, keeps track of Starlink satellites passing by and
| runs out with her phone camera every time they are visible.
|
| She even started to learn English because she wanted to
| understand what they're saying on the live streams. I am
| fixing some production bug at 4 AM and suddenly she's
| texting me like "you're watching the launch too???". And
| last time I forgot to send her the link to the latest
| Starship test she nearly grounded me.
|
| She is a seamstress who never cared about any of this until
| she saw the first landing of Falcon Heavy, proclaimed that
| we live in a fucking scifi and became the biggest Elon Musk
| fangirl I know.
| Cacti wrote:
| Is this something we have evidence for, or is this just in
| theory?
| delichon wrote:
| SpaceX built the biggest constellation to date, and is using
| the profits to build Falcons while designing Starships. Check
| out the resulting cost per kilo to orbit:
|
| https://ourworldindata.org/grapher/cost-space-launches-
| low-e...
|
| That's pretty good for theory.
| bmitc wrote:
| The theoretical part is whether that's actually useful for
| not. Cost per kilo to orbit doesn't magically solve
| astronomical observation problems.
| delichon wrote:
| Don't Chandra, Webb and Hubble, et. al. sufficiently
| prove the usefulness?
| harimau777 wrote:
| It seems to me that one problem is that regular people who are
| interested in astronomy don't have access to space based
| telescopes. I'm not sure I'd want to live in a world where
| there's that degree of class divide between astronomers who do
| and do not have access to that kind of funding.
| sandworm101 wrote:
| From the paper:
|
| >> Astronomy is also engaged in the search for extraterrestrial
| intelligence, a classic example of a program that might proceed
| for many years with little or nothing of interest to report, but
| that might someday provide one of the most profound discoveries
| in human history
|
| That is all well and good. Most HN readers are probably well
| aware of that project. But if you want to alter policy at a
| national or international level, don't talk about
| extraterrestrial intelligence. It stirs the hornets next of
| faith, politics and cultural conflict. It opens the door to
| ridicule. Talk about the search for life, the search for a second
| life-supporting world. And maybe some of that life runs a radio
| station. Just avoid mentioning ET by name.
| jonplackett wrote:
| Is this a bit of a temporary problem, in the the very technology
| causing the issue - substantially cheaper access to space - will
| presumable ultimately put a frikkin massive telescope, or many
| massive telescopes into orbit where they'll also not have to deal
| with the many other issues ground telescopes have to deal with.
|
| I get that this still sucks for any individual with a Telescope
| though.
| runeofdoom wrote:
| It's not just "any individual with a telescope" though. It's
| stuff like the Simonyi Survey Telescope, a set to map the
| southern sky down to below 27th magnitude that's in trouble.
| jonplackett wrote:
| How would a telescope like that compare to Webb or Hubble in
| its capability? Eg, if we had to trade the loss of that for
| many Webb scale telescopes, or presumably something much much
| bigger once starship can start launching - is that worth the
| trade?
| ajford wrote:
| Ok, who funds it? National Science Foundation doesn't
| allocate nearly enough money as it is, let alone enough to
| replace the tens to hundreds of active telescopes producing
| scientific data every night. And those telescopes are
| already oversubscribed with people waiting in line for
| available time. So unless we're slowing astronomy to a
| halt, we'd need similar numbers of telescopes.
|
| And none of that takes into account that many of these
| telescopes are used specifically as experimenter telescopes
| where a given scientist can use their own equipment to
| perform unique observations that cannot be easily done with
| space-based telescopes.
|
| It took over a decade to produce the Webb telescope and get
| it into space, and still is a massive feat of engineering
| not easily reproduced. We're not nearly to a point where we
| can just write off ground-based observatories in place of
| space-based ones.
| runeofdoom wrote:
| My understanding (as a very amateur astrononer) is that
| it's an entirely different sort of scope - very wide field,
| with the ability to track extermely faint objects, rather
| than magnification of a much smaller field. I.e. we'd need
| to build and launch another immense scope to get the same
| sky-mapping ability.
| Havoc wrote:
| As much as I sympathize this feels like a necessary evil to me in
| a sense vaguely accerlationism like.
|
| I do think starlink can do more to help the situation though.
| Sure they tweaked some of the satellites to minimise it, but they
| could do more. Presumably the know the precise location and
| orientation of each sat. Surely that can be packaged into a data
| stream that helps unfk the images? Maybe with a sprinkling of
| that AI musk has going? Astronomers is a pretty small
| crowd...can't be that hard for someone like musk to throw them a
| bone that acknowledges that they're getting the short end here
| LeoPanthera wrote:
| There's no need to predict them in advance. Astronomy photos
| taken from the ground aren't one long exposure. They're lots -
| hundreds even - of short ones, which are then "stacked" to
| reduce noise and increase dynamic range of the final image.
|
| It should be trivial to identify streaks in the stack and just
| throw out those images. I'd be surprised if they're not already
| doing that for the older satellites up there, and things like
| planes flying across the shot.
| throw_pm23 wrote:
| When you are driving towards a wall or a cliff you don't
| necessarily want to accelerate.
| trothamel wrote:
| 30 years ago, it was possible to be lost - not because you wanted
| to be, but because you had no way of figuring out where we are.
| GPS and other GNSS networks have solved that problem.
|
| It used to be possible to not have high-speed internet, and now
| high-speed Internet is available everywhere in the world that has
| an amenable government.
|
| Right now, it's possible to be in a location where it's
| impossible to call for help. In a few years, when LTE-in-space is
| available and the 911 mandate applies to it, anyone with a
| charged phone will be able to get contact.
|
| SpaceX has been working to mitigate how its satellites affect
| astronomy - see https://api.starlink.com/public-
| files/BrightnessMitigationBe... and
| https://new.nsf.gov/news/statement-nsf-astronomy-coordinatio... .
|
| But fundamentally, to limit space to astronomy will be to limit
| the benefits it can give all mankind. a
| shadowgovt wrote:
| Including, notably, better astronomy.
|
| Imagine a radio telescope as a satellite constellation, with an
| aperture the diameter of the orbit if you can synchronize the
| incoming signal with the right math...
| StellarScience wrote:
| There certainly is a real concern for astronomers, but the photo
| illustrations used in the article are selected to make things
| seem worse than they really are. They're wide field of view,
| long-duration exposures. That _used_ to be the way astronomers
| imaged space, with film systems a century ago. But these days
| astronomical telescopes tend to have much narrower fields of view
| (like tiny soda straws peering into one particular spot in space)
| and use image stacking, a technique where many individual images
| are processed to form the final image (very simplistic overview:
| https://www.skyatnightmagazine.com/astrophotography/astropho...
| .) Using image stacking and armed with accurate catalogs that
| predict precisely where every satellite will be at any time,
| enables the removal of satellites during the image stacking
| process. Or they can just use that information for better
| scheduling: wait a minute or two to image a particular spot, so
| there won't be satellites in the field of view.
|
| The article definitely gets this part right:
|
| > "Some astronomers see this as a true 'hair on fire' emergency,
| heralding irretrievable losses to space science; others present a
| more sanguine face, depicting this as yet another challenge to be
| surmounted in surveying a decreasingly pristine sky," Koplow
| remarks.
|
| Being involved in both space and astronomy plants me squarely in
| the latter camp. It takes a bit more work and software, but
| having so many satellites in space is a surmountable challenge
| for terrestrial astronomers. (Not to mention, these days some of
| the best astronomy is performed by telescopes in space, so
| astronomy overall benefits by having easier access to space.)
| shadowgovt wrote:
| Forget satellites; you can't do raw long-exposure for "serious"
| terrestrial-based astronomy anymore because you'll get planes
| in the way.
| gammarator wrote:
| > They're wide field of view, long-duration exposures. That
| used to be the way astronomers imaged space,
|
| Sorry, but one of the two example images
| (https://noirlab.edu/public/images/iotw1946a/) is a single
| 333-second exposure with a modern survey camera, the Dark
| Energy Camera. This is not particularly long nor does it
| represent some outmoded observational strategy. Large, wide-
| field imaging sky surveys (such as the upcoming Rubin
| Observatory) are among the highest-profile ground-based
| astronomy projects today.
|
| Masking and stacking can mitigate the problem but it does not
| of course compensate for the lost area and sensitivity. And the
| brightest satellites (like BlueWalker) saturate the readout
| electronics and spoil the whole exposure.
|
| Narrow field instruments (such as spectrographs) have less
| geometric chance of seeing a satellite but tend to take longer
| exposures (tens of minutes), so there is a greater loss of
| telescope time when a streak does happen.
|
| Even space telescopes are affected by streaks
| (https://www.space.com/hubble-images-spoiled-starlink-
| satelli...).
|
| > It takes a bit more work and software
|
| Equivalently, it takes more money and time. That just means
| less science, given flat to declining funding from Congress.
| shadowgovt wrote:
| I'm sure it's inconvenient, but it's hard for me to believe that
| this isn't a solvable problem.
|
| Satellites have _extremely_ predictable paths and are very well-
| tracked by every government with a space program. If you can know
| a source of noise is there, you can trim the noise out of the
| signal. Sure, this impacts the fidelity of your signal for the
| three-dimensional coordinates of image where the noise was
| present, but "We're getting less science per day" isn't a reason
| to stop the low-orbit satellite boom.
|
| What am I missing here? Can we not do the signal-subtraction? Is
| the problem unsolved or unsolvable? And if it's unsolved... Where
| are the grants to solve it?
| FredPret wrote:
| It'd be so cool if we can put up a huge antenna / scope on the
| far side of the moon. You'd be completely shielded from all human
| noise
| amelius wrote:
| Until we put satellites around the Moon.
| rickydroll wrote:
| 1) Most research is performed on the thousands of smaller
| telescopes (0.5-2 m.) scattered worldwide at private and public
| institutions. Even with the multitude of telescopes in the size
| range, there is still significant contention for scope time.
|
| 2) Space telescopes will never be disposable and will always
| require some form of service, even with high-reliability
| construction.
|
| 3) low Earth orbit is a limited resource and should be managed as
| a worldwide Commons. Allowing private corporations to occupy
| space is another way to privatize profit and push losses onto the
| public purse. Do you think any of these private companies will
| clean up the orbital messes they create, or will they act like
| they have to date?
|
| 4) Satellite Internet solves the billionaire's problem of
| extracting more money from users. Terrestrial methods for
| Internet access are good enough in all but the most remote
| communities. The main problem with terrestrial Internet is
| funding buildout Via private companies in a natural monopoly
| environment.
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