TECHNOLOGY

As SpaceX’s Starlink level goes up, pollution can light up


“It would be difficult to compete against SpaceX in this area, given its clear launch advantage,” Matthew Winzierl, an economist at Harvard Business School who researches space sector marketing, wrote in an email to Wired, even though competitors exist and are being formed, This indicates that the market is still seeing opportunities.

A representative from SpaceX’s communications team declined interview requests from WIRED.

But an Amazon representative noted that the company is aware of potential light pollution issues. “Reflection is a key consideration in our design and development process. We have already made a number of design and process decisions that will help reduce our impact on astronomical observations, and we are reaching out to community members to better understand their concerns and identify steps we can take,” the spokesperson wrote via email .

Katie Dodd, OneWeb’s director of government and corporate affairs in North America, wrote in an email to WIRED that the company is talking with groups, including the UK’s Royal Astronomical Society and the American Astronomical Society, to understand the satellites’ impacts on observations, and to establish design practices. and playback that supports both communities. We are also making brightness measurements and will look at these results to explore solutions.”

SpaceX and its competitors cannot avoid light pollution; They can only reduce it. Every object in the atmosphere reflects at least some light during part of its orbit, depending on its material, color, and size. While satellites send information back to Earth, a tiny amount of sunlight is often reflected, too, through the satellite’s body and solar array.

Early last year, SpaceX tested a Starlink satellite dubbed Darksat, giving it a dark experimental coating on one side, including the antennas, to reduce reflective brightness, which the company claims has been reduced by 55 percent. in a one sheetSome astronomers found that this action darkened the satellite but not to such an extent, although it made the satellite invisible to the naked eye. Aharon He didn’t detect much blackness at all. They found that the measured brightness of the satellite may vary, however, depending on the angle at which it is observed and how the light is scattered through the atmosphere.

according to Publishing on the company’s websiteSpaceX found that dark surfaces became hot, endangering the satellite’s components, and that it still reflected light in the infrared. So the company later tested a different approach it called Visorsat, deploying a number of satellites with installed rectangular sunshades, like those used on car windshields. These masks are intended to ensure that sunlight reflected off the satellite antennas is reflected away from the Earth.

So far, SpaceX hasn’t publicly released any information about how this approach works, or how it compares to Darksat. but Another astronomical world, in an unpublished paper published on the academic preprint server arXiv.org, and Boley’s team in action, both independently found that at least 70 percent of the Visorsat spacecraft were brighter than their preferred threshold: a level that would ensure that Vera C. Robin Observatory images are mostly unaffected.

To draw attention to light pollution concerns and work to develop solutions, the American Astronomical Society held a virtual workshop on satellite constellations this summer, known as SatCon2. They plan to release reports and recommendations soon, in conjunction with a meeting starting on Sunday, called “Dark and calm sky for science and societyOrganized by the United Nations and the International Astronomical Union.

Video: Google

SatCon2 organizers have prioritized reaching out to a wide range of people interested in the night sky, including amateur astronomers, star photographers, the planetarium community, ecologists, and indigenous and tribal communities from the United States, Canada, New Zealand, and other countries. Everyone wanted things to slow down. They want the industry to be more involved. “This is something that belongs to everyone as a global commons,” says Amina Venkatesan, an astrophysicist at the University of San Francisco and co-chair of SatCon2 Public Engagement.

As part of SatCon2, a working group of astronomers spoke with representatives from SpaceX and five other major satellite operators about the limits of reflected light the researchers propose, and how companies can assess and reduce the reflectance of their spacecraft. They also discussed policy options within the United States that could include setting rules for how much light pollution satellites can create for the Internet. These include the possibility of regulations imposed by the Federal Aviation Administration, which sets launch and return conditions, or the Federal Communications Commission (FCC), which licenses radio frequencies into orbit. Some astronomers would also like to see the National Environmental Policy Act end its exemption for space—that is, they see space as an environment in need of protection.



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