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Starlink satellites are 'leaking' signals that interfere with radio telescopes
- sbierwagen 3y ago>Now it is commonplace: sit outside for a few minutes after dark, and you can’t miss them. As always, this is only the case immediately after sunset, when it's dark on the ground but the satellites are still in direct sunlight. Fifteen minutes later they're completely invisible.
- MalcolmDwyer 3y agoThe cutoff is nowhere near that soon after sunset. At midnight? Sure, you're not going to see satellites. But against a dark sky, you can see satellites reflecting for at least a couple hours. They may not be in direct sunlight as it gets later, but they are still illuminated by the atmosphere on the sunny side for a while.
- LightBug1 3y agoThe school children p1ss in the public swimming pool while the adult lanes are still open ... but only during their 1 hour lesson on Monday afternoon. After that, it's totally fine.
- badcppdev 3y agoAdults blame kids for everything. Google it and you'll think twice about swimming in a pool again :-D
- LightBug1 3y agoGave it up long ago!
- pests 3y agoIt is fine though? Swimming pools use a complex chemical and physical filtration system.
- deleted 3y ago[deleted]
- serf 3y agoevery space sci-fi in the world presupposes that we'll do the same once our orbital lanes are packed densely.
- Dylan16807 3y agoLight pollution doesn't linger and spread over time. Once it stops being emitted, it's gone one second later.
- Havoc 3y ago> Fifteen minutes later they're completely invisible. That part of the article is just intro fluff - not the problem described in the article
- makeworld 3y agohttps://james.darpinian.com/satellites/ https://james.darpinian.com/satellites/
- ortusdux 3y agoThis is a key misconception. Their SOP is to put the newest batch into an ultra-low orbit for testing. Any that fail should passively deorbit in a few months due to the increased atmospheric density. To minimize drag during this process, they deploy the solar panels parallel to the ground. Once testing is over, the panels reorient to hide behind the darkened satellite body, and then the satellites use their internal ion thrusters to boost to their final operational orbit. The dawn and dusk flaring people see are these early satellites with horizontal reflective solar panels.
- ortusdux 3y agoThere are reports of people near the poles seeing flares that are, in theory, caused by the vertically oriented panels reflecting the sun from the other side of the earth. Scott Manley - https://youtu.be/P1TsOYcvq9A?si=7yuF2KbQFySDgG31&t=1111 https://youtu.be/P1TsOYcvq9A?si=7yuF2KbQFySDgG31&t=1111
- jychang 3y agoSemi unrelated- I really wonder what uncontacted tribes think of this.
- AgentK20 3y agoSounds like there’s some additional EMI shielding that is needed for future iterations of megaconstellations. On the plus side since they have relatively (compared to geosync satellites) short lifespans of only a few years they can probably sort this out by passively fixing the next generation of satellites. Additionally, from what I have seen of the way they pack the Starlink satellites into the fairing, they seem to be volume constrained in the fairing rather than mass constrained, so there may be additional mass budget available for little overhead.
- schiffern 3y agoI wonder if there's also potential for software mitigations on existing satellites? They already power down the radios when flying over RF quiet zones, so it might be possible to power down (or reconfigure) other components to reduce EMI leakage.
- hoseja 3y agoAfter the first couple space wars we'll have such shielding figured out. Until then, fat chance.
- deleted 3y ago[deleted]
- AniseAbyss 3y ago[dead]
- martinclayton 3y agoI used to work for Starlink. The one that was good for astronomy. https://en.wikipedia.org/wiki/Starlink_Project https://en.wikipedia.org/wiki/Starlink_Project
- saddat 3y agoIn contrast to your values work , I wonder what the benefit of all those satellites should be, besides profit ? It might be easy to say for someone living in a city , but I assume all relevant areas today have somehow internet coverage . So adding 10000s of satellites seems like just the next Netflix , shifting business from one company to another . In difference to GPS , and even ignoring all the impact of all those rocket launches , this is not adding a jot to humanity , and therefore a global light or radio pollution of astronomy is unacceptable
- elcritch 3y agoI’ve lived in a few areas in the US where internet was and still is horrible if available at all. Visiting my mother to help her out for longer than a few days was a pain since she had traditional satellite internet and terrible cell which were unusable for work video meetings. That’s in the US. I doubt every small village in South America or Africa has good internet either. Hopefully they can get starlink and share. Hopefully it’ll give folks more opportunities and access to work or education. Even medical exams over a video call, etc.
- saddat 3y ago[dead]
- fps-hero 3y agoHonestly it’s incredible that sending 12,000 satellites into space to provide internet coverage to multiple continents across the world is as cheaper than installing ground based infrastructure. The cost per satellite is reportedly $500k, so the star link constellation cost only $6 billion. For comparison the Australian NBN (country wide internet infrastructure upgrade) cost over $50 billion, and it still relies on satellites to cover rural areas.
- defrost 3y agoFor anyone with an interest in the computing centre behind a square kilometre radio telescope array see: https://pawsey.org.au/supercomputing/ https://pawsey.org.au/supercomputing/ https://pawsey.org.au/systems/data-cloud/ https://pawsey.org.au/systems/data-cloud/ https://pawsey.org.au/visualisation/ https://pawsey.org.au/visualisation/ Further infomation about the radio quiet zone referenced: https://www.industry.gov.au/science-technology-and-innovation/space-and-astronomy/co-hosting-ska-telescope/australian-radio-quiet-zone-wa https://www.industry.gov.au/science-technology-and-innovatio... and yes it's also in an area with zero ground sourced light pollution - aside from those shiny LEO satellites which are visible long beyond 15 minutes after sunset. They'll even reflect moonlight. From the linked piece from Curtin Uni: We estimate emissions in radio wavelengths will need to be reduced by a factor of a thousand or more to avoid significant interference with radio astronomy. We hope these improvements can be made, in order to preserve humanity’s future view of the universe, the fundamental discoveries we will make, and the future society-changing technologies (like wifi) that will emerge from those discoveries.
- RF_Savage 3y agoFactor of a thousand = 30dB.
- _djo_ 3y agoThat's one of the two Science Processing Centres behind the SKA, the other will be in Cape Town, serving the SKA-Mid array in South Africa. https://www.sarao.ac.za/news/south-africa-will-host-one-of-the-fastest-supercomputers-in-the-world/ https://www.sarao.ac.za/news/south-africa-will-host-one-of-t... https://bandwidthblog.co.za/2023/05/16/supercomputer-south-africa-square-kilometre-array/ https://bandwidthblog.co.za/2023/05/16/supercomputer-south-a... https://www.skao.int/en/explore/big-data/361/science-processing-centres https://www.skao.int/en/explore/big-data/361/science-process...
- aussieguy1234 3y agoWhy not program the satellites to switch of their radio emissions when they orbit over the radio quiet zones?
- schiffern 3y agoThey already do. This isn't about intentional radio emissions, this is radio "leakage" from the onboard electronics, essentially EMI. Strangely there are no legal requirements to limit these emissions, and the detected emissions are so tiny you literally need to point a radio telescope right at the satellite to even detect them. The problem is that even tiny emissions are bad in this case because they're in frequency bands used for radio astronomy. The fix is simple: add more EMI shielding & filtering. The researchers were already working with SpaceX on the problem, and SpaceX had already started making fixes. The researchers pointed this out in the very first paper on the subject, but somehow that detail almost never makes it into the pop-journalism article treatment.... It's good to share these Lessons Learned because SpaceX is doing things nobody has ever done before, and is (rightly) subject to levels of scrutiny nobody has ever seen before. If instead you want to shoehorn this into Elon Bad / SpaceX Bad clickbait, its a non-story.
- adastra22 3y agoThat would get in the way of writing a click-generating Rocket Man Bad article.
- quantified 3y agoIt's heartening that SpaceX engineers want to be good citizens here. I hope the financial side of the house, and other satellite operators, also will work to lower the noise.
- panick21_ 3y agoThey already have done a lot for the visual part, so they seem to be active on these topics.
- defrost 3y ago
- 77pt77 3y agoCan't be! I was assured by everyone that this would never happen.
- spandextwins 3y agoTime to refactor the telescopes. They should do that anyway, Amazon is going to get into the same business soon.
- defrost 3y agoRefactor how, exactly, are you suggesting?
- benatkin 3y agoPut them somewhere away from the low orbit satellites. Maybe GitHub could send a CD with it and do another version of the annoying Arctic Code Vault Contributor badge.
- saddat 3y agoHow about preserving humanity’s capabilities to observe the universe untampered by profit
- schiffern 3y agoMove Fast and Break Things and Don't You Dare Make Me Pay For Damages
- touisteur 3y agoEspecially since public research is so well funded they have the cash to spare to 'refactor' while the private profit-(and king-)making industry surely couldn't handle it.
- troupo 3y agoThere are physical limits on how much stuff you can break (or pollute) before you can't "refactor" yourself out of the hole you've dug
- everyone 3y agoI dont like starlink + all the other frivolous satellites we are throwing up there. All I can think of is Kessler syndrome. Capitalism is destroying the biosphere and now space.
- dkokelley 3y agoSatellites provide humanity a ton of good. Would you say the bad outweighs the good overall? What would you propose we do instead?
- troyvit 3y agoI think it's like calories. They also provide humanity a ton of good but being careless with them is a whole other story.
- hoseja 3y agoStarlink satellites are not in an orbit where Kessler is a problem. Even if they all broke up, the debris would just get dragged down into the atmosphere fast.
- panick21_ 3y ago> All I can think of is Kessler syndrome. Maybe you should consider thinking about more then one thing when trying to understand an issue. Just a suggestion.
- anArbitraryOne 3y agoFunny, they're also 'leaking' signals that interfere with optical telescopes
- zzbn00 3y agoIt will I'm afraid going to be a difficult battle to win, e.g., - modern iPhones can communicate with global satellite constellations (https://support.apple.com/en-us/HT213885 https://support.apple.com/en-us/HT213885). I imagine this will grow substantially - Even bike lights nowdays have radar built into them (e.g., https://www.garmin.com/en-GB/p/698001 https://www.garmin.com/en-GB/p/698001). Also room presence sensors are beginning to use radar 22GHz. We can now build incredibly cheap and lightweight radio devices up to 80 GHz. They will inevitably be used more on the ground, in air and on satellites as the economics makes new types of uses practical.
- n3dm 3y agoThis sucks. More false positives to pick up when driving around town.
- yencabulator 3y agoEven the motion-sensing light in my pantry is a radar now.
- zzbn00 3y agoRight, in principle they are better than just motion sensing since they can also detect breathing (and even heart beating!). And with modules costing 1-2$ people think... why not?
- hoseja 3y agoPut telescopes in space, where they belong. Need a crew? Attach a space station.