Amazon satellites add to astronomers’ worries about the night sky

  • >>Becky Ferreira, The New York Times
    Published: 2020-08-11 10:56:09 BdST

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The 'Milky Way' is seen in the night sky around telescopes and camps of people over rocks in the White Desert north of the Farafra Oasis southwest of Cairo May 16, 2015. Reuters

Welcome to the age of the satellite megaconstellation. Within the next few years, vast networks, containing hundreds or even thousands of spacecraft, could reshape the future of Earth’s orbital environment.

Much of the attention on these strings of satellites has been placed on the prolific launches of SpaceX and OneWeb, but the focus is now turning to Amazon. Last month, the Federal Communications Commission approved a request by the online marketplace to launch its Project Kuiper constellation, which, like SpaceX’s Starlink and OneWeb’s network, aims to extend high-speed internet service to customers around the world, including to remote or underserved communities hobbled by a persistent digital divide.

The Kuiper constellation would consist of 3,236 satellites. That’s more than the approximately 2,600 active satellites already orbiting Earth. While Amazon’s hardware is a long way from the launchpad, SpaceX has already deployed hundreds of satellites in its Starlink constellation, including 57 additional satellites that it launched Friday. It may expand it to 12,000, or more. Facebook and Telesat could also get into the internet constellation business.

The rapid influx of satellites into low-Earth orbit has prompted pushback from professional and amateur astronomers. Starlink satellites are notorious for “photobombing” astronomical images with bright streaks, damaging the quality and reducing the volume of data that scientists collect for research. While SpaceX plans to mitigate the effects of its launches on astronomical observations, scientists and hobbyists in the community worry about the lack of regulation of constellations as more entrants such as Project Kuiper join the action.

“We don’t yet have any kind of industry-wide guidelines,” said Michele Bannister, a planetary astronomer at the University of Canterbury in New Zealand. “We don’t have an industry body that’s producing good corporate citizenship on the part of all of these enthusiastic companies that want to launch, and we don’t have any regulatory setup in place that’s providing clear guidelines back to the industry.”

She added, “To me, honestly, it feels like putting a bunch of planes up and then not having air traffic control.”

BURNING TWILIGHT

Since the first group of Starlink satellites launched in May 2019, many skywatchers have lamented their bright reflected glare. The light pollution is particularly pronounced when the satellites are freshly deployed and headed toward their operational orbits. At this point, they are perfectly positioned to catch sunlight at dawn and dusk, scuttling astrophotos and telescope observations. Starlink must be replenished constantly with new satellites, so these trails will be an ongoing problem.

“Most ground-based observatories actually start in twilight,” said Julien H. Girard, a support scientist at the Space Telescope Science Institute in Baltimore. “We start taking data even when the sky is not completely dark, especially in the near-infrared and infrared wavelengths.”

The satellites may create the most problems for wide-field observatories that survey expansive regions of the night sky at once. The motion of satellites through the frame can obstruct observational targets or overwhelm them with light. Astronomers can use software to remove satellite trails to some extent, but that may not completely fix the images.

“There’s no doubt that the astronomical community can still do science with the presence of those constellations, but it’s a burden,” Girard said.

The light pollution could mess with our view of countless tantalizing astronomical targets. For instance, scientists are beginning to discover interstellar objects in our own solar neighbourhood, such as Oumuamua, a weirdly elongated rock spotted in 2017 that hails from an unknown star system, or Comet Borisov, which was spotted more recently.

Megaconstellations are uniquely positioned to interfere with detections of these cosmic wanderers. “One of the prime discovery times for interstellar objects is in that period of sky near astronomical twilight, or dawn and dusk, which is when these satellites have their biggest impact,” Bannister said.

So far, astronomers have put most of their attention on Starlink because SpaceX was the first company to launch big batches of satellites. OneWeb’s constellation poses a different set of problems for radio astronomers because of the altitude of its orbit. Its future has been uncertain since it declared bankruptcy and began acquisition talks.

But now that Amazon has the FCC’s approval, the Starlink satellites will have company both in orbit and in the discussion about the effects of these networks on astronomy.

“Kuiper would easily have as much of an impact on both optical and radio astronomy as other satellite constellations,” said Jeff Hall, director of the Lowell Observatory in Arizona and chairman of the American Astronomical Society’s Committee on Light Pollution.

The Amazon constellation will have far fewer satellites compared with Starlink, but its array will be deployed into three orbits, all higher in altitude than SpaceX’s network.

“Some of those higher orbits are looking like they are actually going to be more problematic for astronomical imaging, because they are going to be, basically, visible for longer,” Bannister said, although it is not clear how the light pollution from these constellations will compare.

“The companies don’t publish what reflectance their satellites are going to have, so it’s hard to model,” she said.

As the quantity of satellites spirals upward, the risk of crashes does as well. Collisions between satellites add to hazardous orbital debris. Imagine if all the broken glass and prickly detritus from a car wreck kept moving at high speeds above the highway, requiring vehicles to plough through it. That is how the orbital lanes in space work, so it will be essential that protocols governing space traffic are able to keep pace with these megaconstellations to prevent clips and crashes.

Already, there was one alarming incident in which an Earth-observation spacecraft operated by the European Space Agency had to fire its thrusters to dodge a Starlink satellite. A dust-up between the spacecraft was not certain, but the trajectories posed enough of a threat that ESA decided the manoeuvre was necessary. These encounters may become more frequent as thousands of additional satellites take to the sky.

“If this is what we’re having right in the testing phase of these megaconstellations, what’s it going to be like when we have 5,000 of these up, which is what we’re predicted to have launching in the next couple of years?” Bannister said.

BEST BEHAVIOUR

While these concerns have been raised, there is no other obvious way to stop, or slow, the development of these megaconstellations.

“One of the things that I think is most problematic is that there isn’t any legal prevention, or legal protection, for the night skies,” said Chris Newman, professor of space law and policy at Northumbria University in the United Kingdom.

With hundreds of Starlink and OneWeb satellites already launched, and thousands more expected in the next few years, astronomers feel mounting pressure to find a workable compromise with the companies. Decisions made now may affect the sky for decades.

For the moment, that means hashing out a vision of a safe and clear night sky that would rely on voluntary mechanisms.

In response to the light pollution concerns, SpaceX is experimenting with dark coatings and sunshades for its Starlink satellites.

Representatives from Amazon and SpaceX, as well as a consultant formerly with OneWeb, attended a recent workshop called Satellite Constellations 1, organized by the AAS and the National Science Foundation, according to Hall. A report summarizing the results and recommendations of the workshop will be made public in a few weeks. But Amazon has already stated a desire to work with astronomers.

“Reflectivity is a key consideration in our design and development process, and we’re engaging with members of the astronomy community to better understand their concerns and identify steps we can take to minimize our impact,” an Amazon spokesman said. “We’ll have more to share as we release additional detail on our plans for the project.”

But many astronomers, and dark-sky advocates, are seeking a robust regulatory approach to these issues.

“I think the only real way in which, going forward, this is going to develop, is if national regulators make it part of the licensing requirement that satellite companies putting constellations up take into account the needs of ground-based astronomy,” Newman said. “I think that’s very possible, and I don’t think that would require too much accommodation by companies.”

Of course, the night sky is not only a resource for professional astronomers. Across generations and cultures, people have gazed up after sunset to seek solace, enchantment and perspective from the stars. Broadening internet access around the world has an obvious public benefit, but so does the preservation of clear skies and bright stars.

“We’re talking about changing something that is shared across the entire planet,” Bannister said.

“This is environmental impact,” she added. “This is something we know how to discuss and regulate in all the other spheres of corporate activity. Why should this be any different?”

 

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