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Space Science

Does SpaceX's Starlink Project Pose an Existential Threat to Astronomy? (digitaltrends.com) 132

Posted by EditorDavid from the lots-in-space dept.
Earlier this week Forbes reported on two Chilean astronomers "expecting to see images of distant stars and galaxies. Instead, they saw a train of SpaceX satellites crossing the night sky, a worrying sign of what might be to come for astronomy."

Now Digital Trends decries SpaceX's "proposed launch of tens of thousands of satellites into low-Earth orbit where they will form a mega-constellation, making much of our present astronomical efforts impossible." Earlier this month, SpaceX launched another 60 of its Starlink satellites as part of its plan to provide high-speed internet to every part of the planet. However, as useful as this may sound, an astronomer who spoke to Digital Trends said that there are plenty of potential negative ramifications. "Even as professional astronomers, we've only just woken up to the fact that [this had the potential to be] a serious problem in the near future," said Jonathan McDowell, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics.

McDowell has long been an enthusiastic proponent of satellite launches. Since 1989, he has written and edited Jonathan's Space Report, a free internet newsletter which documents technical details of satellite launches. "I'm a little sad to be on the other side of the coin, but I think it's an important issue that needs to be talked about," he said.

McDowell's fear -- shared by others in his field -- is that the sheer number of satellite launches set to take place in the coming years will make it virtually impossible to carry out particular types of ground-based astronomy. Already astrophysicists carrying out long exposures, lasting around 15 seconds, frequently have their images ruined by a satellite trail passing overhead. Many times brighter than the "super faint galaxy" an astronomer might be looking for, this essentially ruins the image. "That's an annoyance, but you work around it," McDowell said. "You take multiple images , trusting that at least one of them will not have the trail. But when we get to the point where there are tens of thousands of very bright satellites in low orbit, the worry is that almost every image you take will have these trails on it... At some point certain types of astronomical observation will just not be feasible any more...."

With Starlink as currently envisaged, when it's fully deployed there will be more naked eye-visible satellites in the sky than there are stars," McDowell continued.... "The sky will be seething instead of static. That is a [major] change to our environment."
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Does SpaceX's Starlink Project Pose an Existential Threat to Astronomy? More

Does SpaceX's Starlink Project Pose an Existential Threat to Astronomy?

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  • Huh? (Score:2)

    by Rei ( 128717 )

    "With Starlink as currently envisaged, when it's fully deployed there will be more naked eye-visible satellites in the sky than there are stars,"

    Visible to the naked eye? What is he, a hawk? Starlink's initial launch was only visible near sunrise / sunset at their initial 280km altitude, but have now dimmed to a level that you need binoculars or a telescope to see them. This before any albedo reductions in the design [twitter.com].

    • We have yet another case of proverbial hand ringing to the tune of not in my back yard!

    • Re: (Score:2)

      by Rei ( 128717 )

      ED: Changed my latitude to one in the US. Looks like about 1 in 4 passes would still be bright enough to be visible (dimly) to the naked eye on the first (non-albedo-dimmed) Starlink satellites. But with some albedo reduction, they should be easily invisible to the naked eye. I'm curious as to whether they've done that with the new batch November batch already, or whether that's yet-to-come. n2yo doesn't have magnitude data for them yet.

      As for astronomy: it's 3x'ing the number of catalogued objects in s

      • Re: (Score:3)

        by Rei ( 128717 )

        To be more explicit: that's 1 in 4 passes "visible" to a person with excellent seeing conditions (mag. 6 limiting). A person living in the suburb of a major city could never spot a Starlink satellite, even if they knew exactly where to look.

    • I think the definition of "naked eye visible" is magnitude 6.5 here, so yeah that's pretty damned eagle eyed with optimal viewing conditions, but it is something at least some people can see with a naked eye. And looking at Heavens Above the first batch sats do sometimes come in as bright an in magnitude 3-4, though most of the time they are more like 5-6. And besides, the problem is what you can see with a telescope, the number of satellites vs stars is just for comparison.

  • Not just astronomy (Score:4, Interesting)

    by Immerman ( 2627577 ) on Saturday November 23, 2019 @12:44PM (#59446052)

    As bad as this will be for astronomy, it could be even worse for the environment. A whole lot of migratory species with very important environmental footprints seem to rely at least partially on stellar navigation, and if most of the "stars" are moving that's likely to become much more difficult - especially to a creature navigating on instinct rather than intellect.

    And the thought of what it will do to those magical night skies alive with stars is just heartbreaking.

    • It's not even bad for astronomy. It's potentially bad for ground-based astronomy, but we resort to that because it's historically been too expensive to put a bunch of telescopes in orbit.

      SpaceX has changed that dynamic. Hubble is great, but a half-dozen half-sized ones would likely be better, if operated as a virtual telescope. We've never considered that, because it's always been cost-prohibitive to do it. The problem described here is also the solution to the problem.

      • It's not even bad for astronomy. It's potentially bad for ground-based astronomy, but we resort to that because it's historically been too expensive to put a bunch of telescopes in orbit.

        Also, the ground-based astronomy can adapt to using a smaller field a view, which would actually improve their light collection ("faster") if their telescopes aperture doesnt also shrink with it.

        I suspect that many of these astronomers dont understand optics. Sure, some do (the ones that build telescopes), but many don't.

        • Re: (Score:3)

          by starless ( 60879 )

          Also, the ground-based astronomy can adapt to using a smaller field a view, which would actually improve their light collection ("faster") if their telescopes aperture doesnt also shrink with it.

          I suspect that many of these astronomers dont understand optics. Sure, some do (the ones that build telescopes), but many don't.

          If there's somebody in this who doesn't understand optics it's you, a "random guy on the internet" rather than professional astronomers.

          • Why assume I am not educated in optics?

            I know why... because when I talked about aperture.. you had no fucking idea what I was talking about, are too lazy to look up why aperture is important in optics, and worst of all you are so ignorant that "all astronomers are equal" in your tiny little uneducated twat brain.

            No, all astronomers are not equal, dipshit. Most could not build a working telescope without following a guide. Full stop.
            • Don't you have it backwards, though? Smaller field of view = longer focal length = slower (higher f-number) for the same physical aperture and sensor size. If this is not what you meant, please elaborate, because the way you worded it sounds like you don't have even a camera shopper's level of understanding of optics yourself.

      • Re: (Score:2)

        by AmiMoJo ( 196126 )

        Problem is you mean "we' as in "the human race". Individual astronomers, individual institutions still can't afford it.

        Also there are types of telescope you can't easily put in orbit due to size, need for maintenance etc.

        • Problem is you mean "we' as in "the human race". Individual astronomers, individual institutions still can't afford it.

          Start a gofundme, pool your money, get a satellite built and launched.

          Also there are types of telescope you can't easily put in orbit due to size, need for maintenance etc.

          Sounds like it's time for some new designs.

      • Re: (Score:2)

        by Strider- ( 39683 )

        Astronomy is one of the few natural sciences where a significant amount of work is done by amateurs in their backyards. It’s not just about the huge telescopes like those in Hawaii or the Atacama... A lot of really good, solid, science has been done by dedicated amateurs with say a 12” reflector in their back yard.

    • Once in their proper orbit they are very dim. I have tried to take a look, and couldn't even see them in a fairly dark area.

      • Re: (Score:2)

        by ngc5194 ( 847747 )

        You have a research grade telescope to test this with? Starlink probably doesn't pose a threat to visual amateurs with small scopes, but these are quite different than the big scopes, you know.

        • Actually, I have access to fairly large scopes. And yes, it impacts the astrophotography and astrometrics we do. But migratory species do not have access to large scopes, so it has little chance of impacting them. Light pollution in general is far worse.

    • Re: (Score:3, Informative)

      by Aighearach ( 97333 )

      especially to a creature navigating on instinct rather than intellect.

      You're not saying that based on intellect, you're saying that because you instinctively place magical capabilities of being Different and Important upon your species.

      Birds fucking know they're migrating. Duh. That's why birds of a species that normally migrate sometimes don't bother when they're living in a city park. They know what migration is. They know why they're migrating. If life is easy they might not bother. They stop along the way, too, and they know why they stop and they know what sort of places

      • No, I'm saying that because intellect makes it easier to separate slow-moving objects from non-moving.

        They, like human navigators of old, almost certainly look up at the bright lights in the sky and follow them as vast stationary landmarks that move only with latitude, season, and time of day.

        Now - double the number of stars, with half of them moving, but slowly enough that you really have to pay attention to notice the motion, but still plenty fast enough that the sky is a constantly shifting swarm of ligh

        • Remember that satellites are only visible at dawn and dusk, when the sky is dark from the ground but you're still near the terminator, and can still see reflected sunlight if it's high enough. Later at night, any satellites will be fully within the Earth's shadow cone and will be practically invisible.

          With that many satellites you might spot the occasional occultation, and telescopes still have real problems, but for you and I and migratory animals the night sky will be unchanged for nearly the entire night

          • For very low orbits true.
            But not for higher orbits or GSO over the equator.
            And looking at lunar eclipses you should know that the core shadow of the earth is rather small as the sun is so big it shines left and right around the earth.
            And finally, there might be interesting targets for observation just during dawn and dusk.

        • with half of them moving, but slowly enough that you really have to pay attention to notice the motion

          This is the part that isn't true, that would need to be true for the whole claim to hold up. If in fact it is obvious that they're moving and the others are stationary, then this problem isn't really a thing.

          You're guessing and waving your hands, and that's enough to as "is this true?" But it isn't enough to say, "This is a real problem that exists."

          • I'm basing it on looking at things like the ISS - easy to spot in the sky, and in a nice low orbit where it's moving about as fast as anything without a highly elliptical orbit can. It's moving - and it's obvious if you sit and stare at it for a few minutes, but you can't tell the difference between it and an bright star or planet with just a glance.

            • Right, exactly, that's worse that being merely ignorant; you suppose it is actually just like whatever popped in your head! Except, it isn't.

              And whatever you thought was the ISS, you were looking at something else. It doesn't sit there in the sky for minutes, it zooms past and is quite obviously moving.

              These are way dimmer than most of the existing satellites that are visible, which are also much dimmer than the ISS.

              • You're out of your league.

                The ISS is easy to recognize with a very modest telescope, nothing else looks remotely like it. And it's very nearly as low and fast as anything can be without air resistance from the upper atmosphere rapidly de-orbitting it.

                It takes roughly 90 minutes to circle the Earth - that's 5,400 seconds to traverse 360 degrees of sky, 15 seconds to traverse 1 degree of sky, or about 7.5 seconds to cross the disc of the sun or full moon. It's moving, but it's not "zipping", and you'll have

      • Re:Not just astronomy (Score:4, Informative)

        by angel'o'sphere ( 80593 ) <angelo,schneider&oomentor,de> on Sunday November 24, 2019 @05:24AM (#59447934) Journal

        Why bother writing such a long post when half of your assumptions are simply wrong?
        https://www.allaboutbirds.org/... [allaboutbirds.org]
        https://web.colby.edu/mainebir... [colby.edu]
        https://www.nytimes.com/1993/0... [nytimes.com]

        • Because I'm not wrong. You didn't say anything, and you'd need some deep understanding instead of beginner links to know which words to say to contradict me.

          You believe I'm wrong. But you don't know why you think I'm wrong, or what I'm wrong about. Pathetic. But also human instinct.

    • > And the thought of what it will do to those magical night skies alive with stars is just heartbreaking.

      In places like Miami, it's semi-moot anyway. We have so much ambient light, you can barely make out anything less bright than Venus. You have to go at least 10-25 miles west of US 27 before the sky really becomes dark enough to see lots of stars with the naked eye... and being in the Everglades in that kind of darkness is *dangerous*.

      Most amateur astronomers I know have pickup trucks so they can drive

      • It is, and that's heartbreaking as well - but it's voluntary. Somewhat at least - a lot of people never know what they're missing. I'm not really into astronomy, but there's something deeply profound in spending long nights eating, drinking, talking, and dreaming under a canopy of stars, occasionally taking time to dwell on the majesty that you're only catching a tiny glimpse of as the Milky Way rises and stars cloud the sky.

  • Astronomers paid by Comcast? Luckily, I don't have to put up with with Comcast, but I was put in a real bind by crappy DSL from Centurylink. You want to talk existential threats? Crappy American Internet is going to actually kill people. The earth has been around for billions of years. We can make it another century or so without pretty space pictures.

  • Can we just skip to the part where the alarmists just make us all go back to living in caves, and allow us out just once a year for Life Day?

    I already have a nice cave picked out so it's cool.

  • If not SpaceX then someone else. It's inevitable that eo is about to fill up with all kinds of junk. Just gonna have to get used to it.
  • Earth based Astronomy is always in danger the better the technology available on Earth gets. After artificial light aka fire was invented, astronomy has been losing ground ever since. Artificial light means light pollution and that hurts astronomy. Then gas light in cities, then electric light all over everyhwere made it a lot worse. Which is why observatories went to deserts in Chile in the first place (apart from the clear and dry air without any clouds). The number of satellites we have in earth orbit h

  • Only at sunrise and sunset (Score:4, Interesting)

    by surfdaddy ( 930829 ) on Saturday November 23, 2019 @02:41PM (#59446318)

    Unless I'm missing something, this seems sensationalistic.
    First, there are currently only about 120 Starlink satellites in orbit, so it's not currently doing more than other existing satellites are doing.
    Second, they aren't going to be lit up once they are in earth's shadow. Since they're only a few hundred miles high, that would only be for a short time after sunset and before sunrise, correct?

    So somebody please explain how even ten thousand satellites in orbit will mess up the night sky once the sun has been down for an hour or so.

    • that would only be for a short time after sunset and before sunrise

      That depends on season and latitude, at higher latitudes during summer they are high enough to be illuminated over the pole the entire night. The closer to equator or winter you get the less time after dusk and before dawn they will be visible.

      • Re: (Score:2)

        by Kohath ( 38547 )

        That depends on season and latitude, at higher latitudes during summer they are high enough to be illuminated over the pole the entire night.

        High latitudes don’t have night during the summer.

        • You must have a strange definition what "high means".
          On a scale from 0 - 90, 45 could be considered high, or 60 could be consider high.
          The polar circle is at 66 degrees ... and nitpicking about "summer" lets you miss spring and autumn.

          High latitudes donâ(TM)t have night during the summer.
          And then again, about how many days of summer do we talk? http://astronomy.swin.edu.au/c... [swin.edu.au]

          And then again and again: the new satellites use all kind of weird orbits, aka polar orbits and such ... so yes: you see them i

        • Mkay let's quantify "high latitudes" a bit, New York and London count in this context. https://youtu.be/Wm6G6N5u0IA?t... [youtu.be]

      • at higher latitudes during summer they are high enough to be illuminated over the pole the entire night

        That's a bad place/time for astronomy anyway.

    • First, there are currently only about 120 Starlink satellites in orbit, so it's not currently doing more than other existing satellites are doing.

      Which is precisely why now is the time to complain. Doing it later is pointless. If I told you I was about to punch you, would you ask me not to? Or would you wait for me to do it and then ask me not to? To be clear, this is already a problem, it's not something new that Starlink poses.

      So somebody please explain how even ten thousand satellites in orbit will mess up the night sky once the sun has been down for an hour or so.

      The satellites are still very much visible to sensitive astronomical equipment, even basic cameras can pick up many which are not reflecting the sunlight, but rather could be either reflecting the earth's glow or in some case

  • No, this will be a boon to astronomy (Score:3)

    by RhettLivingston ( 544140 ) on Saturday November 23, 2019 @03:22PM (#59446422) Journal

    Astronomers just need to get with the program and follow the dots to its implications.

    Starlink is just the first real result of a much lower cost for getting things into space. For less than what it costs to create the highly adaptive optics necessary to improve ground-based telescopes, astronomers should soon be able to put massive telescopes in space. Even better, with a bit more development, they could have their own constellations of telescopes designed to work in array configurations with apertures larger than Earth, perhaps even utilizing optical interferometry if they can get that to work through space instead of through fiber. Optical interferometry in space would no longer be limited in resolution by atmospheric effects.

    Alternatively, you could launch a single package with many modules that spin out on cables to create a rotating scope with an aperture with the radius of the cable lengths - perhaps miles wide - that is optically connected through fiber to the hub. If they're real nice, maybe Elon would even pay for some of it to get super high resolution images of the Mars.

    Another possibility would be to develop a super small scope to be added to every Starlink to create a massive array that could easily be configured to be many virtual arrays at once with a 24x7 360 degree sphere of view.

    That brings to mind a barely related tangent, I wonder if a Starlink phased array antenna can made to do double duty as a passive radar receiver. Stealth vehicles aren't designed to be stealthy from above or below. There should be a fair amount of energy already being emitted by these and other satellites that could be reflected back. With laser coordination between multiple sats, I would think triangulation could be very accurate. Perhaps the military has already considered this when they looked at utilizing Starlink.

    • Astronomers just need to get with the program and follow the dots to its implications.

      You have a very strange view of what the field of Astronomy actually does. Hint: There are more than just a handful of astronomers in the world playing with a few ultra expensive telescopes.

  • Long-exposure astronomy on ground-based telescopes using chemical film media could obviously be affected, but even so, if you have orbital parameters for all these satellites, it shouldn't take a huge effort to use such the data to figure out when to temporarily close a shutter to keep them out of the picture, at least when you're looking at a small part of the available sky.

    If you're looking at a large portion of the sky for a long period, you'll already have the problem of airplanes, helicopters, weather

  • Seriously, if you look at the history of human civilization whenever we open a new frontier of any kind we start off by eventually polluting the crap out of it until it's almost completely ruined, then we go "Oops!" and 'fix' it. Are we doing the same thing with our own near-space?
  • Just an idle thought: how will even more RF emissions from orbit affect radio astronomy? Signals from deep space, dozens/hundreds/thousands of lightyears away are incredibly faint. Is the signal processing from radiotelescopes so good that they can filter these signals out well enough?

  • but would a non-reflective coating on the satellites be an option? We get stories here on a semi-regular basis about a new material that absorbs 9x.x% of light. Maybe this could be a practical application? Obviously you can't coat solar panels but keep them pointed away from earth.

    I don't know enough about the field to know if this would be in any way practical.

    • They did tone them down some in the latest version. I can imagine problems with going all the way with that though. Non-reflective = absorptive. Thus, when in the sun, they could be challenged in cooling themselves. Also, astronomy is a full spectrum activity. I don't think there is a full spectrum absorptive coating.

      But, the biggest problem is the solar panels. Their surface has to be transparent to the bands they convert and one of the biggest challenges in space-based solar panels is keeping them cool. I

  • This will at most be an inconvenience to astronomers. They will simply have to set up some software that has the tracking information of all the satellites if they do not use this already. Shutter systems if not already on telescope sensors will need to be added. And just before the satellite flies into view shut the shutter. Once it's past open the shutter. Wide field of view images might have more of an issue narrow field of view should not. Seems more likely this is a red herring being sent out to try

    • It's less of a problem than that. Modern telescopes don't use film they use CCD's and software can define how they integrate the image over time.

      But this is more just people being upset that the night sky won't be pristine not some kind of weird conspiracy.

  • People keep saying this but when I calculate the actual effect on big research telescopes the effect seems to be virtually nil.

    For instance GMT has something like a 400 arcsec^2 FOV for the main imager from the best info I can find. There are 148510660 square arcminutes in the sky. So there are about 2227680 patches of that size in the sky and assuming that each starlink satellite occupies a disjoint 400 arcsecond square that still means only 1 in 1800 patches are filled at any given time. The orbital perio

    • Note the disjointness assumption is a worst case scenario. In actual fact there will probably be some overlap.

      The basic point is that modern telescopes can simply ignore the time the satellite is in focus and integrate their image as if that time didn't happen. It's not like we still use film.

  • The solar cell panels are already black.

  • Yes, optical astronomy is doomed by the proliferation of satellites in Earth orbit.

    The solution is to build really enormous telescopes on the far side of the Moon.

    Or, since very few human eyes are pressed to the eyepieces of telescopes, program the computers that DO most of the astronomical research to recognize satellites, and ignore them. Most satellites are in published orbits, so it should be relatively easy to identify satellites and digitally "remove" that pixel from the processed computer image.

  • The issue is far more nuanced than the original hit piece makes out.

    These birds are at LEO, which means the trails are primarily a problem when sighting at dawn/dusk or when sighting towards the horizon adjacent to these periods.

    Yes, you CAN see satellites at midnight, but those are slow moving NEO birds, not LEO ones.

    Starlink is designed to fly very low, which in turn means that the ground timing of their effects is also confined to periods close to the local terminator. This is _not_ an astronomical apoc

  • We survived the Iridium flare phenomenon along with others. We'll survive this.

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