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Such concerns prompted a major conference this week, organized by the International Astronomical Union\u2019s Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference, known as CPS. It\u2019s being held in the Canary Islands, where there are several observatories. It\u2019s the first in-person meeting of its kind, bringing together scores of astronomers, as well as satellite industry representatives, advocates of Indigenous and environmental perspectives, and policy experts.<\/p>\n
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\u201cWe\u2019re on the cusp of a new era with a crowded, large zoo of satellites. Having a bunch of bright satellites in the sky will be very disruptive to astronomy,\u201d says Aparna Venkatesan, an astrophysicist at the University of San Francisco who spoke at the meeting about environmental and cultural views of the night sky. She coauthored an earlier study about how satellite proliferation boosts the risks of collisions in low-Earth orbit and increases the amount of space junk. The CPS meeting was delayed multiple times because of COVID and a volcano eruption, so it\u2019s long overdue, Venkatesan says. \u201cBut in a way, waiting has been a gift, because the astronomers and modelers and data takers have been able to organize.\u201d<\/p>\n The United Launch Alliance Atlas V rocket is transported from the Vertical Integration Facility to Space Launch Complex-41 at Cape Canaveral, Florida, in preparation to launch Amazon\u2019s Project Kuiper Protoflight mission.<\/p>\n Credit: Astronomers are concerned that bright satellites can photobomb images and interfere with radio receivers, degrading astronomical data. A team working on the Vera Rubin Observatory in the Chilean Andes, which will become one of the most powerful telescopes on Earth when it opens next year, has proposed a brightness limit of apparent magnitude 7. (Apparent magnitudes describe how bright something appears on Earth, not its absolute brightness. A distant galaxy can have a fainter magnitude than a nearby star or a much closer satellite.) But most members of satellite constellations glow much brighter than that, at least part of the time.<\/p>\n Satellite networks also create a diffuse light in the night sky, even from orbiters that aren\u2019t individually visible. That light will only brighten if satellites collide, creating reflective bits of flying junk that can\u2019t be masked in images. Starlink satellites have been involved in many near misses, including flying near China\u2019s Tiangong space station.<\/p>\n ,<\/p>\n While ground telescopes are the most impaired, a few space telescopes, especially Hubble, have been affected too. Since Hubble orbits slightly below some networks of satellites, a small but increasing percentage of its images have streaks in them.<\/p>\n The conference organizers emphasize that astronomers generally don\u2019t oppose satellite constellations, which can deliver broadband access, navigation, and other important services. \u201cThe potential benefits to humanity are great, but so are the associated concerns. Creative solutions and technological innovation are needed to confront and solve these problems,\u201d the conference\u2019s website states. But the attendees are struggling to address interference thanks to satellites\u2019 growing numbers. \u201cFrom the astronomy point of view, there\u2019s nothing we can do to stop this. It\u2019s time to mitigate the effects and reduce the impacts,\u201d says Mike Peel, an astronomer at the Instituto de Astrof\u00edsica de Canarias, who co-leads the CPS\u2019s group focused on adapting observation strategies.<\/p>\n Astronomers like Harrison Krantz at the University of Arizona are using telescopes to bear witness to these challenges. \u201cThese satellites are going to make astronomy more difficult, but not impossible. Let\u2019s assess the situation and see what tools we have at our disposal,\u201d Krantz says. For example, sometimes astronomers can use software that masks pixels affected by streaking. They can also time some observations to avoid clusters of satellites, or avoid pointing their telescopes where satellites are brightest. Krantz and his colleagues recently published the results of a 2.5-year comprehensive survey finding that, despite some astronomers\u2019 assumptions, satellites tend not to be brightest at zenith, or directly overhead, where they\u2019re closest in range. Instead they\u2019re brightest at mid-elevations opposite the sun. Adapting observations isn\u2019t always possible, though\u2014meaning some crucial data will be lost.<\/p>\n ,<\/p>\n Satellites also have a long history of interfering with radio telescopes, including the LOFAR network of low-frequency antennas and the Atacama Large Millimeter Array in Chile. Radio signals and electromagnetic radiation from satellites can create static that mimics signs of the cosmic phenomena astronomers are trying to study.<\/p>\n \u201cIt was always clear that satellites would have this effect, because all electronics have this. It\u2019s inevitable. We knew there would be leaked radiation, but we didn\u2019t know till now how much,\u201d says Benjamin Winkel, an astronomer at the Max Planck Institute for Radio Astronomy in Bonn, Germany, who is attending the conference.<\/p>\n Winkel coauthored a study published earlier this year about the radiation levels and frequencies measured from 68 Starlink satellites that passed through the LOFAR station\u2019s beam during an hour of observation. Winkel says SpaceX has attempted to move radio traffic to other frequencies when their satellites fly above telescopes, and to keep their radio beams from being pointed too closely at them. But Winkel\u2019s paper concluded those efforts were insufficient, because telescopes are still sensitive to satellites\u2019 internal electronics. \u201cWhen we looked, something popped up, much brighter than anticipated. It\u2019s not a needle in the haystack,\u201d Winkel says, referring to the electromagnetic radiation from satellites\u2019 onboard electronics.<\/p>\n Astronomers at the conference have some key fixes they want from the space industry: to darken satellites to at least magnitude 7, to avoid interfering with \u201cradio-quiet zones\u201d around telescopes, to avoid radio frequency bands near the ones telescopes use, and to share more information with the astronomical community. Winkel points out that international regulations limit how much electromagnetic radiation smartphones and TVs can leak\u2014but so far these rules haven\u2019t been applied to satellites.<\/p>\n ,<\/p>\n National regulations and international policies have been moving slower than innovation. Only voluntary changes have emerged so far. For example, SpaceX attempted to add visors to its satellites to block sunlight from hitting the bottom of the chassis, according to a company white paper in 2022. The visors did seem to dim the glint, but they got in the way of a new optical communications system, so the company abandoned the visors, according to SpaceX\u2019s paper.<\/p>\n SpaceX has also tried adding coatings to the body of its spacecraft to darken them, and Krantz\u2019s team concluded that it did make them a bit fainter. That\u2019s significant progress, though the satellites are still 2.5 to 6 times brighter than the magnitude 7 threshold astronomers can live with, Krantz says. SpaceX has also begun experimenting with a \u201cdielectric mirror film\u201d to further darken its newest generation of satellites and allow radio waves to pass through them, according to the white paper.<\/p>\n Representatives from SpaceX did not respond to WIRED\u2019s requests for comment. But Patricia Cooper, a former SpaceX vice president, told WIRED: \u201cSpaceX has put a lot of money, a lot of time, and a lot of thought into its corrections.\u201d Cooper is now the president of Constellation Advisory LLC, a group that advises satellite companies on policies and regulations. \u201cI am concerned that persistent calls to alarm without a meaningful focus on solutions will deter companies from trying,\u201d she says.<\/p>\n In an emailed statement, Amazon spokesperson Brecke Boyd wrote: \u201cAs part of our prototype mission, we\u2019ll test an anti-reflection method on one of the two satellites to learn more about whether it\u2019s an effective way to mitigate reflectivity.\u201d The company also plans to use steering and maneuvering capabilities to orient the solar array and spacecraft to minimize reflection from surfaces, according to that statement.<\/p>\n ,<\/p>\n Starlink now comprises more than half of all satellites in orbit, and SpaceX is seeking regulatory approval for 30,000 more. Amazon has some catching up to do, though the company plans to fill out its fleet of more than 3,000 by 2029. Both companies\u2019 networks will fly at similar altitudes: between 342 and 392 miles above the Earth. Other networks include OneWeb, which has more than 630 satellites orbiting at a much higher altitude\u2014750 miles. They are therefore dimmer, but take longer to pass out of a telescope\u2019s field of view.<\/p>\n AST SpaceMobile\u2019s BlueBird network of communications satellites could number 150 or more, with more than 100 planned for launch by the end of next year. The new Nature<\/i> paper, produced by a team of about 40 researchers, found that its prototype, BlueWalker 3, launched in 2022, reflects more light than almost any star. It is also rather large by satellite standards, at nearly 700 square feet including its broad solar array. \u201cBlueWalker was a shock to us as to how bright it was. We are also very worried about the impact to radio astronomy,\u201d since one of its downlink frequencies is next to a protected radio band at 42.5-43.5 gigahertz, says John Barentine, one of the study\u2019s coauthors and a conference attendee. A Tucson, Arizona-based astronomer, he is also the executive officer of Dark Sky Consulting, which advises companies and government officials on outdoor lighting to preserve dark night skies.<\/p>\n \u201cWe are working to address the concerns of astronomers,\u201d wrote Scott Wisniewski, AST SpaceMobile\u2019s chief strategy officer, in an email to WIRED. That includes using roll-tilting flight maneuvers to reduce the satellites\u2019 brightness, and preventing them from transmitting near radio telescopes. The company is also planning to equip its next-generation satellites with anti-reflective materials, Wisniewski wrote.<\/p>\n Astronomers and industry representatives have more work to do to find solutions. \u201cMaybe the best we can hope for now is a somewhat uneasy coexistence\u201d with industry, Barentine says. The two have to share a single resource: the night sky. \u201cMy hope is that we can find a way to do it that minimizes harm to astronomy,\u201d he says.<\/p>\n This story originally appeared on wired.com.<\/em><\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Amazon is set to launch two satellite prototypes for its Project Kuiper network, which will eventually number more than 3,200 orbiters. Project Kuiper could become a rival to SpaceX\u2019s Starlink constellation, which is now nearly 4,800 strong. Amazon\u2019s launch is planned for 2 pm Eastern time today, with a backup launch window tomorrow. This rapid […]<\/p>\n","protected":false},"author":1,"featured_media":45845,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[1661,5546,9769,9605],"class_list":["post-45842","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-astronomy","tag-light-pollution","tag-project-kuper","tag-syndication"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45842"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=45842"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/45842\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/45845"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=45842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=45842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=45842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"\"](\"https:\/\/cdn.arstechnica.net\/wp-content\/uploads\/2023\/10\/ula.jpg\")
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\n United Launch Alliance<\/p>\n<\/figure>\n