At the #AAS238 public policy session, charts by Pat Seitzer (presented by Richard Green) show that Starlink visorsats are 4x dimmer than the original ones, although at mag ~6.5 not quite yet at the goal of mag 7 or fainter.
A similar chart for OneWeb satellites show they’re around mag 7.85. However, at their higher altitudes they’re visible longer each night.
But does the public really care about megaconstellations interfering with astronomy? Lawrence describes the “loss of the sky” as “the final straw” for the public in broader concerns about the environment. But, despite visions offered by some astronomers of satellites crisscrossing the night sky, those satellites will be invisible to people in light-polluted cities and suburbs. The VisorSat versions of Starlink, in fact, are too dim to see with the naked eye in all but the best viewing conditions once in their final orbits. (They are more readily visible during their orbit-raising process, an issue SpaceX has also been trying to address.) They certainly pose a hazard to both professional and amateur astronomers, but their concerns may not be shared by the wider public.At the end of book, Lawrence points readers to a petition demanding that the FCC withdraw licenses for Starlink and other megaconstellations. That petition has attracted only about 17,400 signatures since November 2019 (16,787 when Lawrence wrote that section of the book, published early this year.) That’s… not a lot. By contrast, an odd petition demanding that Washington’s Reagan National Airport be renamed after a teenage pop star has received more than 73,000 signatures since this spring. The public is more interested in pop stars than celestial stars.Fortunately, public interest isn’t required to try and solve this problem. It can be included into broader discussions about space sustainability that include ways to mitigate the growth of orbital debris and clean up existing debris. Given the glacial pace of international proceedings, engagement with companies, like what astronomers have been doing with SpaceX since 2019 that led to things like VisorSat, offers the best path to near-term solutions to solving the problem. If astronomers wait for the diplomats to act, the sky may well be lost—at least for them.
Last year Scientific American was the first outlet to report on a paper in the Vanderbilt Journal of Entertainment and Technology Law that argued that the Federal Communications Commission’s (FCC’s) approval of mega constellations such as Starlink may have been in breach of U.S. environmental law—specifically, the National Environmental Policy Act (NEPA). Since 1986, the FCC has had a “categorical exclusion” that means almost none of its activities require an environmental review under NEPA. The paper argued this exclusion should no longer be valid, considering the FCC’s current activities, particularly its licensing of satellites in space. “It’s clear from a legal standpoint that the FCC is not following NEPA,” says Ramon Ryan, a recent law graduate of Vanderbilt University and the paper’s author.Questions remain, however, over arguments that NEPA should extend to space. To date, no court has ruled on the issue. Now the matter is set to be put to the test: The California-based communications company Viasat, which operates a rival satellite Internet service, submitted a filing to the U.S. Court of Appeals for the District of Columbia Circuit asking for a reassessment of the FCC’s licensing of some Starlink satellites. While the filing only relates to a recent modification to lower the planned altitudes of about 3,000 Starlink satellites, the case could set a precedent that will force the agency to consider any future satellite licenses’ impact on the night sky.[...]Even if SpaceX is willing to voluntarily address the impacts of its satellites on the night sky, there are concerns that other countries and companies might not be so cooperative. China, which has plans to launch a constellation of 13,000 satellites, has been characteristically silent on the issue. Lynk, a U.S. company that wants to launch 5,000 satellites, did not respond to a request for comment. Amazon plans for a more than 3,000-strong Project Kuiper constellation.
Two years ago, when astronomers gathered at the 234th meeting of the American Astronomical Society (AAS) in St. Louis, one word was on the minds of many attendees: Starlink. Just a few weeks earlier, SpaceX had launched the first set of 60 Starlink satellites, and the unexpected appearance of the satellites in twilight skies as a bright string of pearls dismayed astronomers. With SpaceX planning to launch potentially tens of thousands of such satellites, astronomers had visions — or, more accurately, nightmares — of a ruined night sky.At the 238th meeting of the AAS, held online in early June, the threat posed by Starlink didn’t seem nearly as urgent among attendees as it did then, or at the next AAS meeting in January 2020 that devoted a special session on the subject. One reason may be that virtual meetings, even with chat rooms and Slack channels, can’t replicate the hallway discussions at in-person conferences where people share what they really think about such topics.Another, though, is that astronomers have made progress mitigating the threat through cooperation rather than confrontation. Meetings between astronomers and SpaceX have led to design changes to the Starlink satellites, including the “VisorSat” design where a visor prevents sunlight from reaching reflective surfaces like antenna panels. SpaceX has launched about 1,000 VisorSat versions of Starlink.
A multibillion-dollar radio telescope is moving into its construction phase while still working to raise funding and deal with satellite megaconstellations whose interference “change the game” for their plans.In a June 29 talk at the annual meeting of the European Astronomical Society, Philip Diamond, director general of the Square Kilometer Array (SKA) Observatory, announced that the observatory’s council had formally approval plans to move into the construction phase of the radio telescope.
Diamond said the SKA was in technical discussions with satellite operators on mitigation measures “that would significantly limit the impact on the SKA telescopes.” He didn’t elaborate on the specific measures.During a talk at the conference July 2, Federico Di Vruno, spectrum manager of the SKA Observatory, said the observatory had developed “flagging and excision” technologies to identify radio-frequency interference by satellites and removing it from the data. “This represents a loss of observing time,” he said, but such interference from the constellations by OneWeb and SpaceX would account for less than four percent of observations.
With slow progress on regulation and policy, astronomers are making progress on other approaches to mitigate the effects that satellite megaconstellations will have on their observations.At the conclusion of the weeklong SATCON2 workshop July 16, astronomers announced a proposal to develop a virtual center called SatHub that will provide tools for astronomers to avoid satellite passes in their observations or correct observations affected by such passes.“The idea here is to have a one-stop shop for all of your different needs pertaining to low Earth orbit satellite constellation observations,” said Meredith Rawls of the University of Washington, chair of the workshop’s observations working group, at a press briefing about the workshop July 16.
As I dug into the issue, I found myself wading into a legal debate. Observatory staff and scientists initially told me in no uncertain terms that the facility could push back against any source of radio interference in town, be it Wi-Fi or a smartphone, a microwave or a malfunctioning electric blanket. But when I raised the issue with scientists and officials in the greater radio astronomy community, I was told that West Virginia’s law against radio noise was essentially toothless, meaning Niday had no power to crack down on Wi-Fi, smartphones, microwaves, and other reportedly “outlawed” electronics.I would eventually bring the debate to Anthony Beasley, director of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, which oversaw Green Bank’s operations from 1956 until 2016, when the two entities split. The NRAO still operates telescopes around the world and has a vested interest in maintaining the Quiet Zone. Beasley agreed there was ambiguity to the Quiet Zone regulations. But he said the argument was somewhat removed from reality. Even if the state and federal laws could be interpreted in their strictest possible way, it still wouldn’t make financial or logistical sense to hunt Wi-Fi up and down the valley. For a cash-strapped observatory fighting to merely stay open, why hire lawyers to prosecute Wi-Fi-users when that money could go toward scientific equipment, staff, and research?“You’ve got to decide which hill you’re going to die on,” Beasley said. “Taking someone to court and potentially getting some kind of class action lawsuit going would be an incredible waste of time, in my opinion.”
Telesat close to completing Lightspeed fundingQuote from: SpaceNewsTelesat is close to securing all the funds it needs for Lightspeed, after the Canadian government said it would inject more than a billion dollars into the low Earth orbit constellation.The government plans to invest 1.44 billion Canadian dollars ($1.15 billion) in the project, which aims to start launching a network of nearly 300 broadband satellites next year.In return, Telesat will invest in Canadian infrastructure to build out Lightspeed, including hundreds of jobs and scholarships.It means Telesat has now made arrangements for about 4 billion Canadian dollars of funding for Lightspeed, more than two-thirds of its expected overall cost. Telesat has put a $5 billion price tag on Lightspeed, or 6.3 billion Canadian dollars.
Telesat is close to securing all the funds it needs for Lightspeed, after the Canadian government said it would inject more than a billion dollars into the low Earth orbit constellation.The government plans to invest 1.44 billion Canadian dollars ($1.15 billion) in the project, which aims to start launching a network of nearly 300 broadband satellites next year.In return, Telesat will invest in Canadian infrastructure to build out Lightspeed, including hundreds of jobs and scholarships.It means Telesat has now made arrangements for about 4 billion Canadian dollars of funding for Lightspeed, more than two-thirds of its expected overall cost. Telesat has put a $5 billion price tag on Lightspeed, or 6.3 billion Canadian dollars.
The number of satellites in low-Earth orbit is increasing rapidly, and many tens of thousands of them are expected to be launched in the coming years. There is a strong concern among the astronomical community about the contamination of optical and near-infrared observations by satellite trails. We analyze the impact analysis of such constellations on optical and near-infrared astronomical observations in a rigorous and quantitative way, using updated constellation information, and considering imagers and spectrographs and their very different characteristics. We introduce an analytical method that allows us to rapidly and accurately evaluate the effect of a very large number of satellites, accounting for their magnitudes and the effect of trailing of the satellite image during the exposure. We use this to evaluate the impact on a series of representative instruments, including imagers (traditional narrow field instruments, wide-field survey cameras, and astro-photographic cameras) and spectrographs (long-slit and fibre-fed), taking into account their limiting magnitude. As already known (Walker et al. 2020), the effect of satellite trails is more damaging for high-altitude satellites, on wide-field instruments, or essentially during the first and last hours of the night. Thanks to their brighter limiting magnitudes, low- and mid-resolution spectrographs will be less affected, but the contamination will be at about the same level as that of the science signal, introducing additional challenges. High-resolution spectrographs will essentially be immune. We propose a series of mitigating measures, including one that uses the described simulation method to optimize the scheduling of the observations. We conclude that no single mitigation measure will solve the problem of satellite trails for all instruments and all science cases.
Analytical simulations of the effect of satellite constellations on optical and near-infrared observations
Welcome to the Action Against Satellite Light Pollution website (AASLP). Our movement is dedicated to asking probing and necessary questions, whilst seeking answers as to whether individuals and organisations who are affected by satellite light pollution were consulted first? What efforts, if any are being made by the corporations who run these satellite programmes to mitigate and minimise the adverse impacts that their actions have on the human right to view a dark and uninterrupted night sky? Satellite light pollution and radio interference cause major problems for astronomers, both professional and amateur. Other vital astrophysical scientific research is also becoming impossible to undertake, past examples of which, communication satellite technology would not have been ‘realised’ without it. Our goal is to inform and encourage questioning by global citizens and if possible engage an active movement against the unjustified exploitation of our commonwealth… the night sky.
The U.S. National Science Foundation commissioned a study by the independent science advisory group JASON to assess the impact of current and planned large satellite constellations on astronomical observations in 2020. The charge for JASON was to:* Understand the types and numbers of spacecraft planned for launch in the next decade.* Understand the current regulatory process for commercial launches to Low Earth Orbit, both in the U.S and internationally.* Characterize the types of interference that spacecraft could have on observations of multiple types, specifically in the optical and infrared wavelength regimes.* Gather and describe the range of observations currently being made and foreseen for the future.* Suggest any additional data that should be gathered to better understand the scope of the problem for the future.NSF commissioned the report as a resource for all stakeholders. The JASON group had broad discretion in constructing its report and identifying relevant issues. The report sets benchmarks and the foundation for discussing the impacts on astronomy at various wavelengths.NSF is reviewing the report's findings and recommendations and intends to continue to work with stakeholders on the development of mutual solutions.Please review the full PDF report.Recent and upcoming relevant activities and events can be found at the following:* Report from the Dark and Quiet Skies conference sponsored by the UN Office of Outer Space Affairs and the International Astronomical Union and at the request of the United Nations Committee on the Peaceful Uses of Outer Space* Satellite Constellations 1 report* Satellite Constellations 2 workshop, July 12-16, 2021* Dark and Quiet Skies for Science and Society Conference, October 3-7, 2021* NSF's Spectrum Innovation Initiative* Radio Spectrum Coordination Agreement
Soon after the launches began, lawyers and activists got involved, asking pointed questions about whether near-Earth space—once the domain of nations and militaries, now open to businesses and billionaires—was an environmental commons in need of protection, like a forest or river. Executives such as Musk pushed back, arguing global broadband would be a boon for poor, isolated communities desperate for online opportunities. But Tyson [Tony Tyson, Chief Scientist for the Large Synoptic Survey Telescope], for the moment at least, wanted to avoid public conflict. He emailed a former contact at SpaceX, hoping to speak engineer-to-engineer as he would have in his Bell Labs days.And so it was that Tyson and several colleagues found themselves on the phone with Musk himself, negotiating the first chapter in an ongoing environmental dispute over who exactly decides the future of the sky. According to other people on the call, Musk said that if astronomers were clever, they would just put their telescopes into space, where the seeing was better anyway. But doing that would cost 10 or 100 times more, the astronomers replied—and if SpaceX was clever, their engineers could just solve the satellite brightness problem cheaply.Tyson, explaining the technical needs of the Rubin detector, pushed for dimming the satellites by a factor of 30 or even 100—with Musk balking at the latter figure. But at the end of the conversation, Musk turned to some SpaceX engineers on the call. “Fix this,” he said.
The Satellite Constellations 2 (SATCON2) workshop, held 12–16 July 2021, brought together more than 350 astronomers, satellite operators, dark-sky advocates, policy experts, and other stakeholders from 40 countries to discuss how to implement the strategies and recommendations emerging from the 2020 SATCON1 workshop to minimize the negative impacts of satellite constellations on astronomy and the night sky. The executive summary of the SATCON2 report is released today online. The full report, which will add the detailed reports of the four SATCON2 working groups to the Executive Summary, will be released in the near future.
Conclusions from Satellite Constellations 2 ReleasedQuoteThe Satellite Constellations 2 (SATCON2) workshop, held 12–16 July 2021, brought together more than 350 astronomers, satellite operators, dark-sky advocates, policy experts, and other stakeholders from 40 countries to discuss how to implement the strategies and recommendations emerging from the 2020 SATCON1 workshop to minimize the negative impacts of satellite constellations on astronomy and the night sky. The executive summary of the SATCON2 report is released today online. The full report, which will add the detailed reports of the four SATCON2 working groups to the Executive Summary, will be released in the near future.https://noirlab.edu/public/products/techdocs/techdoc031/
....For the TL:DR crowdSuggesting a global public info sharing group/portal/clearing house from the observation side of things called SatHub run by a new IAU2 "Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference", with a expanded remit from visible wavelengths to an expanded EM spectrum. They want operators to submit new orbit data every 8 hours or when a maneuver happens (whichever is first). They also want relevant metadata for sats such as reflectivity/BRDF/EIRP, transmission bandpasses, nominal flux density, etc so basically satellite profiles. Operators should emit orbital data in standardized formats, leaning strongly on both plaintext NASA Modified ITC Ephemeris format (like SpaceX), as well as OMM format from CCSDS 502.0-B-2 that Celestrak likes. Orbital data will not be overwritten/erased, allowing for historical comparison, with relevant search capability in open source software tools allowing for translation/conversion to alternate formats and ephemerides like TLE. For added fun, they want the megaconstellation operators to foot the bill for the SatHub public portal website.They also want operators to consult with indigenous communities under Duty to Consult, as they tend to get forgotten.They also want industry to slow down deployments until a regulatory framework is in place (fat chance of that). They think the OST provides a partial legal mandate to deal with visible light pollution at least.....
....With respect to rising space traffic issues, having the IAU fronting what effectively is the beginnings of an international space traffic control system by establishing the tracking capabilities is not entirely unreasonable. But, dealing with legacy space assets/debris tracking, plus military reluctance to distribute TLE's and satellite profiles make this difficult...
Hossen Teimoorinia, a researcher at the University of Victoria, Canada, has been experimenting with different techniques for a while. "If you want to remove satellite traces to find moving objects you need to prepare a very good dataset," he tells El Reg.Not only do you have to collect images from observatories and institutions, they need to show exactly the same region of space with and without satellite interference and have to be pre-processed to make sure they're the same size and resolution, and so on. The other possibility is to add fake, artificial trails in clean images of the night sky to increase the amount of training examples."It's a little bit time consuming. But hopefully we will be able to train one main model and use transfer learning so it can be fine-tuned to handle different images taken from different telescopes," Teimoorinia says.
