Upcoming big satellite constellations vex and worry astronomers

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Astronomers are expressing increasing distress over the possible negative consequences to their Earth-based telescope observations from the several new giant satellite constellations being launched by SpaceX and others.

[M]any astronomers worry that such ‘megaconstellations’ — which are also planned by other companies that could launch tens of thousands of satellites in the coming years — might interfere with crucial observations of the Universe. They fear that megaconstellations could disrupt radio frequencies used for astronomical observation, create bright streaks in the night sky and increase congestion in orbit, raising the risk of collisions.

The Nature article then details the issues faced by some specific telescopes. Hidden within the article however was this interesting tidbit that admitted the problem for many telescopes is really not significant.

Within the next year or so, SpaceX plans to launch an initial set of 1,584 Starlink satellites into 550-kilometre-high orbits. At a site like Cerro Tololo, Chile, which hosts several major telescopes, six to nine of these satellites would be visible for about an hour before dark and after dawn each night, Seitzer has calculated.

Most telescopes can deal with that, says Olivier Hainaut, an astronomer at the European Southern Observatory (ESO) in Garching, Germany. Even if more companies launch megaconstellations, many astronomers might still be okay, he says. Hainaut has calculated that if 27,000 new satellites are launched, then ESO’s telescopes in Chile would lose about 0.8% of their long-exposure observing time near dusk and dawn. “Normally, we don’t do long exposures during twilight,” he says. “We are pretty sure it won’t be a problem for us.” [emphasis mine]

The article then proceeds with its Chicken-Little spin as if the astronomical world is about to end if something is not done to stop or more tightly control these new satellite constellations.

As indicated by the quote above, it appears however that the threat is overstated. The constellations might reduce observing time slightly on LSST, scheduled for completion in 2022 and designed to take full sky images once every three nights. Also, the satellite radio signals might impact some radio astronomy. In both cases, however, the fears seem exaggerated. Radio frequencies are well regulated, and LSST’s data should easily be able to separate out the satellite tracks from the real astronomical data.

Rather than demand some limits or controls on this new satellite technology, the astronomical community should rise to the occasion and find ways to overcome this new challenge. The most obvious solution is to shift the construction of new telescopes from ground-based to space-based. In fact, this same new satellite technology should make it possible for them to do so, at much less cost and relatively quickly.

But then, astronomers are part of our modern academic community, whose culture is routinely leftist and therefore fascist in philosophy (even though they usually don’t realize it). To them too often the knee-jerk response to any competition is to try to control and squelch it.

We shall see if the astronomers succeed in this case.



  • David Eastman

    I continue to be amazed at the people, “scientists” among them, who place esoteric research above progress. These satellite constellations will do far more for mankind, and even for the scientific community, then the telescopes they block, even if they really did present a serious issue, which as you mention they don’t.

    The planetary protection people are just as bad if not worse. The people who just don’t want us ruining a pristine virgin planet I discount entirely, but the scientists who “but having astronauts there will ruin our data!”… the only interest I have in investigating the soil on Mars, or Luna, is to use that knowledge to enable astronauts to go there to gather more data, and hopefully start colonies, so that eventually it’s not just astronauts that can get off Earth. If conducting your science gets in the way of the actual objective of that science, I’m sorry, you lose.

  • Edward

    One would think from the article that the astronomers have completely failed to learn the advantages of telescopes in space. Hubble and Kepler are two of the recent famous ones, but there have been a few others.

    One of the disadvantages of ground based telescopes is that they are virtually useless during the day. There is also the problem of the atmosphere and what astronomers call “seeing,” the amount of twinkling of stars and other objects. Cloudy days — er — nights, too.

    Using space based radio telescopes could also be beneficial, because right now there are only a few very narrow radio frequencies that are set aside for astronomy. Space based telescopes, especially if they are located on the far side of the Moon, could greatly expand the frequencies that they could monitor.

    Using a space telescope is not that much different than using a ground based telescope. Long gone are the days when an astronomer spent sleepless nights in the cold observatory building looking through an eyepiece. These days astronomers work at their desks, viewing on their computer monitors the data coming in from the telescope — based anywhere — that they have finally been given time on, whether that be the ground based Kit Peak or space based Hubble.

    And there are fewer confused Hawaiians trying to stop the construction and operation of space based telescopes.

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