AAS Issues Position Statement on SpaceX’s Satellite Constellations

Telescopes at Lowell Observatory in Arizona captured this shot of galaxies May 25. Their image was marred by the reflected light from more than 25 Starlink satellites as they passed overhead. (Credit: Victoria Girgis/Lowell Observatory)

American Astronomical Society Statement

On May 23rd entrepreneur Elon Musk’s company SpaceX launched 60 Starlink communication satellites aboard a single rocket. Within days skywatchers worldwide spotted them flying in formation as they orbited Earth and reflected sunlight from their shiny metal surfaces. Some people, unaware that artificial satellites can be seen moving against the starry background every clear night, reported UFO sightings. Astronomers, on the other hand, knew exactly what they were seeing — and immediately began to worry.

SpaceX had suggested that the satellites would be visible just barely, if at all. But for a few days after launch the Starlink constellation shone as brightly as many astronomical constellations, and SpaceX intends to launch thousands more such spacecraft as part of an effort to provide internet service to everyone in the world. “I think it’s commendable and very impressive engineering to spread the information and opportunities made possible by internet access,” says Megan Donahue (Michigan State University), President of the American Astronomical Society (AAS), “but I, like many astronomers, am very worried about the future of these new bright satellites.” The Starlink satellites and similar swarms being developed by other companies could eventually outnumber the stars visible in our night sky.

On June 8th, at the 234th AAS meeting in St. Louis, Missouri, the AAS Board of Trustees adopted the following position statement on satellite constellations:

The American Astronomical Society notes with concern the impending deployment of very large constellations of satellites into Earth orbit. The number of such satellites is projected to grow into the tens of thousands over the next several years, creating the potential for substantial adverse impacts to ground- and space-based astronomy. These impacts could include significant disruption of optical and near-infrared observations by direct detection of satellites in reflected and emitted light; contamination of radio astronomical observations by electromagnetic radiation in satellite communication bands; and collision with space-based observatories.

The AAS recognizes that outer space is an increasingly available resource with many possible uses. However, the potential for multiple large satellite constellations to adversely affect both each other and the study of the cosmos is becoming increasingly apparent, both in low Earth orbit and beyond.

The AAS is actively working to assess the impacts on astronomy of large satellite constellations before their numbers rise further. Only with thorough and quantitative understanding can we properly assess the risks and identify appropriate mitigating actions. The AAS desires that this be a collaborative effort among its members, other scientific societies, and other space stakeholders including private companies. The AAS will support and facilitate the work by relevant parties to understand fully and minimize the impact of large satellite constellations on ground- and space-based astronomy.

“The natural night sky is a resource not just for astronomers but for all who look upward to understand and enjoy the splendor of the universe, and its degradation has many negative impacts beyond the astronomical,” says Jeffrey C. Hall (Lowell Observatory), Chair of the AAS Committee on Light Pollution, Radio Interference, and Space Debris. “I appreciate the initial conversation we have already had with SpaceX, and I look forward to working with my AAS colleagues and with all stakeholders to understand and mitigate the effects of the rapidly increasing numbers of satellites in near-Earth orbit.”

AAS President Donahue adds, “I’m looking forward to productive conversations between astronomers and SpaceX. I fully expect that we will come up with creative solutions that can serve as models for other companies to follow.”

The American Astronomical Society (AAS), established in 1899, is the major organization of professional astronomers in North America. Its membership of approximately 7,500 also includes physicists, mathematicians, geologists, engineers, and others whose research interests lie within the broad spectrum of subjects now comprising the astronomical sciences. The mission of the AAS is to enhance and share humanity’s scientific understanding of the universe, which it achieves through publishing, meeting organization, education and outreach, and training and professional development.

  • voronwae

    Those who believe that astronomy and the natural night sky must be sacrificed to the greater good of SpaceX, its future missions to Mars, and human spaceflight in general need to remember something: the universe is our greatest physics laboratory.

    By sacrificing our ability to observe the cosmos from Earth, we may actually be setting ourselves back scientifically for decades as we work to overcome what companies have done to benefit their shareholders, without the consent of the rest of humanity. It will be a long, long time before space-based astronomy puts even a scratch in what’s being done on the ground. In addition, I, for one, would be horrified to lose the beautiful stillness of the night sky.

  • Emmet Ford

    Your concerns about ground based astronomy are warranted. But I think fears about about plainly visible satellites outnumbering the stars in the sky have been greatly overstated, and I cannot help but suspect that this was done maliciously. The other explanation is that astronomers, those folks who actually look up for a living, thought it was entirely plausible that satellites so small that they can fit into a single 5-meter fairing in batches of 60 are somehow going to be orders of magnitude brighter than any of the communication satellites launched to date.

  • publiusr

    Hey, these are also the same guys who would prefer we get mugged than to have streetlamps, so….

  • Lee

    Wrong. 1) There are DOJ studies that show there is no link between less lighting and increased crime. Apparently, convicts want to be able to see what they are doing. 2) Astronomers and the IDA don’t oppose lighting, just bad lighting that wastes much of the light above the horizon of the fixture, where it does no one any good. Lighting engineers agree with us, which is why most new fixtures don’t pollute. 3) Fixtures that glare in your eyes are worse than no lighting. They make it impossible to see in the shadows.

  • publiusr

    Easy, killer 😉
    Good points actually.

  • redneck

    Point 1 is wrong. There is no link because anyone with brains avoids unlit areas in the bad parts of town if at all possible. And in the better parts of town as well given reasonable alternatives. Predators go where the victims are.

  • Lee

    Respectfully, you don’t know what you are talking about. The study corrected for the factors you mention. I’m at home in the dark, having grown up in the country. The predators hide in the impenetrable shadows caused by the bad lighting. I know lots of people who grew up in big cities. Without exception, they hate the dark for the reasons you mention. But guess what? The convicts grew up in the city too, and also hate the dark.

  • redneck

    Do you realize that you have contradicted yourself?