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Satellite megaconstellations could have 'extreme' impact on astronomy, report finds

An image from the Cerro Tololo Inter-American Observatory shows streaks left by Starlink satellites.
An image from the Cerro Tololo Inter-American Observatory shows streaks left by Starlink satellites.
(Image: © NSF's National Optical-Infrared Astronomy Research Laboratory/CTIO/AURA/DELVE)

Huge constellations of internet satellites could fundamentally change how astronomers study the night sky and how the rest of us experience it, a new report finds.

The potential impacts of megaconstellations in low Earth orbit (LEO), such as SpaceX's Starlink network, "are estimated to range from negligible to extreme," according to a report from the Satellite Constellations 1 (SATCON1) workshop, which was released Tuesday (Aug. 25).

SpaceX has already launched about 600 Starlink satellites, and that's just the beginning. Elon Musk's company has approval to operate 12,000 Starlink spacecraft and has applied for permission for up to 30,000 more. And SpaceX is not alone; for example, Amazon aims to launch about 3,200 broadband satellites for its own network, known as Project Kuiper.

Related: SpaceX's Starlink satellite megaconstellation launches in photos 

For perspective: There are currently about 2,500 operational satellites circling Earth, and humanity has launched fewer than 10,000 objects since the dawn of the space age in 1957.

The actual impact of this LEO population boom on the night sky depends on a number of factors, including the nature and goals of the observations being made; observers' ability to remove or mask satellite trails in their datasets; and the number, brightness and altitude of the satellites, the report's authors determined.

For instance, satellite trails will pose a particular problem for telescopes that view wide swaths of sky in visible and infrared light, such as the upcoming Vera C. Rubin Observatory in Chile.

Observing programs that rely upon data gathered during the twilight hours, such as searches for potentially hazardous asteroids and comets, will be disproportionately affected as well. That's because LEO satellites will remain illuminated by the sun at these times, the report explains.

But big LEO networks could pose problems throughout the night if their constituent satellites are high enough up. For example, a large constellation orbiting 750 miles (1,200 kilometers) above Earth, as OneWeb's 74 broadband satellites do, "will be visible all night during summer and significant fractions of the night during winter, fall, and spring, and will have negative impacts on nearly all observational programs," the new report states

(OneWeb had intended to launch at least 650 internet satellites, but it's unclear if the constellation will ever get that big. OneWeb declared bankruptcy this year and will be bought by a consortium led by the British government and the Indian company Bharti Global.)

Constellations that orbit less than 370 miles (600 km) above Earth won't have nearly the same all-night impact, the report's authors determined. Starlink falls into this category; its satellites fly at an altitude of about 340 miles (550 km).

It's quite early in the megaconstellation buildout, so there's still time to minimize the deleterious effects of the satellite swarms. And the new report lays out some recommendations for doing just that, including:  

  • Deploy satellites no higher than 370 miles (600 km);
  • Reduce satellites' brightness by controlling their orientation, darkening them and/or shading their reflective surfaces (as SpaceX is starting to do with Starlink craft); 
  • Support the development of image-processing software that minimizes the impact of satellite trails;
  • Make satellites' orbital information available so astronomers can point their telescopes away from them.

The report also recommends launching fewer or no LEO megaconstellations, noting that this "is the only option identified that can achieve zero impact." But it seems naive to think this one has a chance of being followed.

The SATCON1 workshop was organized by the U.S. National Science Foundation's NOIRLab and the American Astronomical Society and held virtually from June 29 to July 2, 2020. You can read the full report for free here.

Mike Wall is the author of "Out There" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook. 

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  • Mergatroid
    I feel companies putting these "constellations" up should have to pay for any mitigation astronomers must do to compensate for problems caused by the satellites.

    What's next, ads on the surface of the Moon?
    Reply
  • newtons_laws
    Mergatroid said:
    I feel companies putting these "constellations" up should have to pay for any mitigation astronomers must do to compensate for problems caused by the satellites.

    What's next, ads on the surface of the Moon?
    Arthur C.Clarke's 1956 short story "Watch this Space" tells how a scientific experiment conducted on the Moon - creating a giant sodium cloud that is made luminescent by the Sun's rays and visible from Earth - is sabotaged by "the greatest advertising coup" in history (strongly implied to be by Coca-Cola) ;) https://en.wikipedia.org/wiki/Venture_to_the_Moon
    Reply
  • Dr Bugsy
    The Man That Polluted Space.
    Reply
  • Lorne
    Admin said:
    Huge constellations of internet satellites could fundamentally change how astronomers study the night sky and how the rest of us experience it, a new report finds.

    Satellite megaconstellations could have 'extreme' impact on astronomy, report finds : Read more
    Really, read the article again. It says there are about 10k
    satellites in LEO, Even in LEO any satellite is hard to find
    and is more than 100k away . They are all in very predictable
    orbits. They are tracked by NASA and we know where they
    all are.

    Now think about aircraft. At any time there are 10s of
    thousands of them. They are tracked but much more
    randem than Satellites. They all fly under 10k altitude so
    they appear much larger. The astronomiers work through
    them so the satellites should be trivial.

    I think they whine too much.
    Reply
  • Chris Coles
    By chance, I may be able to open this debate up from past experience. During 1986, the European Space Agency announced a competition to celebrate the centenary of the design and construction of the Eiffel Tower in Paris France. With the help of Alan Jefferson, at the time senior lecturer in the Aero & Astro dept university of Southampton; we presented the concept of a Space Chronometer, an orbiting hour, minute and second hand giving Greenwich Mean Time to the entire planet. At the time of the result we received an honour's exceptional, (and dare I say, were both credited with the same technological foresight as Gustav Eiffel a century before. Soon afterwards, I helped out the Eiffel Tower at an major Aerospace conference in Brighton, who were presenting the competition results. Particularly there were people of the highest level attending, and I had the interesting experience of having the Secretary general for the European Space Agency stand in front of me to announce; "This project shall not fly . . . it harm's science". Our proposal, The Space Chronometer, was later published in Leonardo. Again, not long after that conference there was very wide publicity in the likes of New Scientist, denouncing the whole idea of anything orbiting the planet that would detract from humanities view of the surrounding universe. I have to say I am amazed that the astronomical science community has remained so silent about this ongoing deployment.

    Now, by pure chance, being the inventor of the camera phone with GPS, I have had some experience of dealing with the United States Federal Communications Commission, FCC, and I am not at all surprised that they have taken it upon themselves to set about the destruction of our view. Again, we must also assume that these satellites will be transmitting 5G which many, including me; believe such transmissions to be presenting an existential threat to the health of humanity. And when that existential threat becomes a reality; and the health of humanity becomes deeply affected by the transmissions; how are we going to bring a stop to their mission? Food for thought?
    Reply
  • Torbjorn Larsson
    The conference discussion were doing the rounds at the time, so no surprises there.

    Nice to see them written up!
    Reply
  • Torbjorn Larsson
    Mergatroid said:
    I feel companies putting these "constellations" up should have to pay for any mitigation astronomers must do to compensate for problems caused by the satellites.

    They are paying both taxes and - in the case of the manufacturer that cooperates - research as well as technical mitigation.

    What more would you expect? Telecom companies in general do not pay astronomers directly for the trouble they cause radio astronomy. Instead these things are regulated.

    We should also remember that those who *will* pay for these services are mostly the poorest billion that live with little if any infrastructure. Mobile phones have observably been reducing risk (say, fish fleet communication), kick starting economy (ibid) and contributes to education.

    Dr Bugsy said:
    The Man That Polluted Space.

    What "man", these are companies!? Though if the UK government (bought OneWeb) or Amazon (plane to launch Kuiper) doesn't start to cooperate, we can start pointing fingers. And unfortunately their orbits are planned to be in the most sensitive orbits. Yikes!

    Chris Coles said:
    we must also assume that these satellites will be transmitting 5G which many, including me; believe such transmissions to be presenting an existential threat to the health of humanity.

    Despite that the science say there is no such threat, and despite that you align with the UK conspiracy theory terrorists that sabotage important infrastructure - an "airy" debate can be had, but these problematic things must be pointed out first!? Also, how would satellites transmitting different protocols differ in EM characteristics?

    We who go to this site for the science do not have to "assume" or "believe" anything. Such arguments go to the round bin (but can be remarked on if they are morally doubtful as here).
    Reply
  • Jeff W
    Mergatroid said:
    I feel companies putting these "constellations" up should have to pay for any mitigation astronomers must do to compensate for problems caused by the satellites.

    What's next, ads on the surface of the Moon?

    I appreciate science and astronomy, but I feel your opinion is somewhat one sided. The satellites creating this problem are for the Starlink constellation which will be bring broadband to communities worldwide. Their orbits are well known and can be compensated for.

    In the USA alone there are 19 million people who still do not have access to broadband. How is it that astronomers having clear and unobstructed views of the sky so much more important than the rest of the world having access to broadband? Broadband is used for everything today. Education and learning, shopping, news, … Astronomy makes great scientific discoveries but, does that really mean astronomer’s needs come before everybody else’s?

    Maybe if the astronomers fighting Starlink get their way, they should have to pay for terrestrial broadband solutions to be extended to every corner of the earth?

    What’s next, to lessen the light pollution we’ll have black outs in all cities so astronomers don’t have to leave their back yards to look at the sky.
    Reply
  • Chris Coles
    Torbjorn Larsson said:
    They are paying both taxes and - in the case of the manufacturer that cooperates - research as well as technical mitigation.

    What more would you expect? Telecom companies in general do not pay astronomers directly for the trouble they cause radio astronomy. Instead these things are regulated.

    We should also remember that those who *will* pay for these services are mostly the poorest billion that live with little if any infrastructure. Mobile phones have observably been reducing risk (say, fish fleet communication), kick starting economy (ibid) and contributes to education.



    What "man", these are companies!? Though if the UK government (bought OneWeb) or Amazon (plane to launch Kuiper) doesn't start to cooperate, we can start pointing fingers. And unfortunately their orbits are planned to be in the most sensitive orbits. Yikes!



    Despite that the science say there is no such threat, and despite that you align with the UK conspiracy theory terrorists that sabotage important infrastructure - an "airy" debate can be had, but these problematic things must be pointed out first!? Also, how would satellites transmitting different protocols differ in EM characteristics?

    We who go to this site for the science do not have to "assume" or "believe" anything. Such arguments go to the round bin (but can be remarked on if they are morally doubtful as here).

    Who paid for the science that you so eloquently quote?
    Reply
  • Lorne
    Mergatroid said:
    I feel companies putting these "constellations" up should have to pay for any mitigation astronomers must do to compensate for problems caused by the satellites.

    What's next, ads on the surface of the Moon?
    Reply