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Astronomers organize lobbying group to block satellite constellations

The International Astronomical Union (IAU) has now created an office to lobby governments worldwide to block the coming commercial launch of numerous satellite constellations.

The IAU claims that the first goal of this new office will be to study the effects of these satellites on ground-based astronomy accompanied by an effort to work with industry to mitigate those effects.

That is a lie. This is the office’s real purpose:

Another role for the center will be to create national and international laws and norms for what regulators allow in orbit. “We need to codify these good intentions, to have some backup,” says Richard Green of the University of Arizona’s Steward Observatory. “We’ll take a two-pronged approach: Cooperate and develop legislation to apply if necessary.” IAU and other bodies are working to convince the United Nations’s Committee on the Peaceful Uses of Outer Space of the need for legislation. “We are confident that we will have guidelines that will have to be followed by companies in the near future,” Benvenuti says. Cosmologist Aparna Venkatesan of the University of San Francisco says it would be good if there were laws in the United States and elsewhere that echoed the influential U.S. Clean Air Act: “Many of us dream of a Clean Skies Act.”

Rather than realize that things are changing and Earth-based astronomy is becoming obsolete, the astronomers wish to use the force of law to block progress by others so that they can continue to live in the past.

The time to have moved all cutting edge astronomical research off the planet arrived more than three decades ago. The astronomers refused to recognize this, focusing instead on building giant telescopes on the ground that had less capability than the Hubble Space Telescope and were dogged by political and engineering challenges that hindered their success.

Had astronomers instead focused on building many small orbiting optical telescopes, the threat of satellite constellations now would be minimal. Instead, astronomers would be poised to build the bigger space-based telescopes they need. Instead, they are grounded, with the needed future space-based telescopes possibly decades away.

Conscious Choice cover

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Conscious Choice does more however. In telling the tragic history of the Virginia colony and the rise of slavery there, Zimmerman lays out the proper path for creating healthy societies in places like the Moon and Mars.


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All editions are available at Amazon, Barnes & Noble, and all book vendors, with the ebook priced at $5.99 before discount. The ebook can also be purchased direct from my ebook publisher, ebookit, in which case you don't support the big tech companies and I get a bigger cut much sooner.


Autographed printed copies are also available at discount directly from me (hardback $24.95; paperback $14.95; Shipping cost for either: $5.00). Just email me at zimmerman @ nasw dot org.


  • J Fincannon

    Has anyone looked at the impact of LEO satellites on astronomy? I was looking at and it seemed to indicate to me that while dawn and dusk viewing for astronomers would be reduced somewhat, they still have a lot of the night to do their work.

    For example, for Feb 7 at a spot at ~41 N latitude, the duration of astronomical night is 10 hr 33 min. Of that time, you can see any Starlinks only a total of 1 hr 44 min during this period. Thus, the astronomers have the remaining 8 hr 49 min to do their thing without worrying about Starlink, although they still have to worry about 20 other older non Starlink satellites.

    Based on this, I am led to believe that some astronomers are whiners.

  • Gary

    Eventually, I think Musk might defuse this by funding, building and launching his own space based telescope. With his launch capabilities, he could do it faster and cheaper than any governmental agency.

  • JhonB

    So, how many people need internet, and how many people have had their view blocked by one of Musk’s satellites when looking to the stars? And what about the rest of the world companies that have started or will start their own network?
    Grated, its an issue for them, but a solution for many, many, many more.

  • Ray Van Dune

    I still have not seen a good analysis of the relative impacts on astronomy of reflected satellite light vs light obscured by satellites.

    Reflection can only occur near sunrise and sunset, unless the satellite is at a very high altitude, which will make the reflection both small and infrequent.

    Obscuration can occur at any time, but can only occur with low-altitude satellites that are of substantial size, and obscuration can only subtract a tiny fraction of a second of data.

    I have used many non-quantitative terms like “tiny”, “substantial” and “infrequent”. While I think they are fair, I lack the training to quantify these factors. There are no doubt many with the skills to analyze these effects, and I hope someone will! Until then, I am unsure whether we have a problem or not!

  • Ray Van Dune

    Obviously the nature of the observing instrument has an impact on the influence of reflected / obstructed light. Initially I simply assumed that professional observations would tend to use narrow FOV instruments, but then I realized that survey-type instruments could profitably use a wide FOV that relied on computer processing to handle many targets at once! Oh well!

  • jburn

    Why couldn’t satellite constellations be a solution versus a problem?

    Musk has demonstrated a technology similar to swarming drones but in low earth orbit for communication. With this same technology base, a cluster of mirrors could be launched and oriented in deep space to produce a huge mirror which could be incrementally expanded.

    This same technology base could be used for space based solar electric power generation. Rather than a single massive structure — instead, a structure of many smaller integrated parts.

  • Trent Castanaveras

    A short time ago during the National Academies presentation, Elon stated almost exactly that, by fitting lensing to a Starship body:

    Comment starts @ 11:48.

  • Trent Castanaveras

    The source of using the Starship body actually comes from a tweet around the same time period of that video presentation. An article around that particular concept here:

  • Trent Castanaveras

    Right? I’ve read somewhere that 3 to 10 hubble class telescopes (2.4 meter diameter or so) on station keeping orbits many kilometers from each other would be able to resolve astonishingly small details, similar to using radio telescope arrays.

    I couldn’t find a recent reference to that particular concept, but did find this:

    Starship will make projects like this child’s play. Tourists will complain about all the astronomers’ telescopes ruining their glorious space views.

  • Edward

    I remember a time when city lights were a problem for astronomers. The atmosphere has always been a problem for them, too. Then there are the not-in-my-back-yard communities and governments that are outright hostile to ground-based astronomy. One would think that astronomers would have learned from the Hubble telescope that space-based astronomy has tremendous advantages.

    But astronomers don’t want to rely on companies’ goodwill.

    Demoting Pluto was a disappointment, but the IAU has lost me with their regression away from cooperative liberty to favor government tyranny.

    For instance, the Vera C. Rubin Observatory, due for first light in 2023, will have as many as one-third of its images ruined by satellite streaks during part of the night.

    Wait until they realize that geostationary satellites are almost always lit up and cause streaks all through the night, not just part of the night.

    A decade ago, there was a company, Planetary Resources, that wanted to mine asteroids, but to finance itself until that became practicable they would launch space-based telescopes. Too bad the astronomy community didn’t get behind them, back then, but instead allowed billions of dollars to be overspent on Webb rather than on solutions to the problems they are experiencing. The solution was right there, but the astronomers were — and remain — myopically short sighted.

  • john hare

    With all the rush to be the biggest victim, perhaps the current underserved areas file a class action suit against the astronomers.

  • J Fincannon

    To Ray Van Dune,

    I had not considered the possibility of obscuration of celestial bodies by the Starlink satellites.

    Assume the maximum cross-sectional area of Starlink is 34 m^2. The average cross-sectional radius is (34m^2/pi)^.5=3.29m. Assume the closest altitude to the satellite over the telescope is 550 km. The solid angle formula for Celestial objects ( ) is 2*3.14159*(1-(d^2-R^2)^.5/d), where d is distance to object and R is the radius of object. The solid angle of one Starlink under these worse cases is 2*3.14159*(1-(450000^2-3.29^2)^.5/450000)=1.68E-10 steradians. For comparison the Sun is 6.794E−5 steradians, the Moon is 6.418E-5 steradians. The entire celestial sphere is 12.566 steradians. But we can only see theoretically half of the celestial sphere from the ground. So, 6.28 steradians for a hemisphere. So, one Starlink can block 1.68E-10/6.28*100=2.67E-9% of the celestial hemisphere. With 1000 Starlinks, 2.67E-06%. With 10,000 Starlinks, 2.67E-05% of the celestial hemisphere is blocked. For the Sun, percentage of the hemisphere it uses is 6.794E−5/6.29=1.08E-3%. Moon is 1.02E-3%. Of course, this calc assumes these Starlinks are all in the same hemisphere side, typically half will be on one side and half on the other.

    So, even in this case, the blockage by Starlink for 10,000 Starlinks seems trivial.

  • Ray Van Dune

    J Fincannon, thanks for your interesting analysis! Using a similar technique, would it not be possible to also assume the angular Field of View (FOV) of a set of typical astronomical instruments, ranging from amateur telescopes to professional observatories, and assuming a given population of such instruments in use, calculate the likelihood that any instrument would be interfered-with?

    Thus might one make the statement that the chance that any telescopic observation is interfered with is X%, or once in every X minutes (or hours, days, months, years…) of observing?

  • J Fincannon

    Ray Van Dune,
    Perhaps. The problem is that I do not know if it matters how long the occultation is occurring. Looking at a star, the passing of a Starlink relative to this narrow field of view is very brief. So I am not sure it matters. The atmosphere itself has variations of density which cause twinkling. I have seen images of the ISS “blocking” the Moon. It is very tiny and brief.

  • Ray Van Dune

    Yes, J Fincannon, until we understand the modes of “interference”, it is hard to model it, isn’t it? I recall seeing the statement that a certain number of images were “ruined” by the passage of a satellite… but is that artistically, or scientifically?

    As an amateur skywatcher myself I don’t want to come off as against the pros, but I feel like we need more specifics about their concerns.

  • J Fincannon

    Ray Van Dune,

    Yes, we should follow the science. I have not seen their defense other than they were ticked off by the bright Starlink satellites. Yes, it might be a nuisance but the sky belongs to everyone.

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