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An image of the Australian desert illuminates satellite pollution
- WalterBright 2y agoJust paint the satellites black?
- pixelesque 2y agoMight then have a lot of overheating satellites :)
- WalterBright 2y agoPut the black surface an inch away from the satellite, supported by standoffs. That'll keep the heat away from the satellite. Also, the black surface only needs to be on the Earth facing side.
- goku12 2y agoIt isn't that simple, is it? Even if you place the black surface on a spacer (adding mass, might I add), the black surface itself is going to radiate heat back onto the satellite via blackbody radiation. This is always going to create a worse thermal situation unless you can somehow radiate away as much heat as you could with reflections. To see what I mean, check out JWST's thermal shield.
- qingcharles 2y agoTo complicate it further I thought that some of the military sats had rotating black panels to shield them from ground visibility?
- goku12 2y agoIt's likely that military satellites used a bunch of tricks to hide itself. But I don't know how useful they are these days. All major space powers have radars powerful enough to easily pick them out. They're needed for satellite collision avoidance analysis.
- WalterBright 2y agoConsider a shaped charge. It seems wild to me that you can direct an explosion with various shapes of the explosive. Perhaps a similar idea can apply to the blackbody radiation - get it to radiate mostly away from the satellite. Also, the black part will be pointed at the Earth, not the Sun.
- perihelions 2y agoNot sure what geometry you're thinking of. Whatever idea it is, you're stuck dealing with Kirchoff's law, which says optical emissivity and absorptivity are the same number at any given wavelength. I.e., you can't create "one-way trap doors" for heat flow—that would be a Maxwell's demon. Stacking multiple surfaces isn't a way to circumvent this. If it's just an asymmetric shape, with different material surfaces pointed in different directions, than that of course is permitted. https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_r...
- WalterBright 2y agoKirchoff's law doesn't say which direction it emits in. As shaped charges can alter the direction of where the blast wave goes, I suspect an analogous behavior of a heat shield can direct where the emissions go. I.e. as you say, an asymmetric shape. PS I haven't done thermo in nearly 50 years!
- perihelions 2y agoV-groove radiators are a really neat, unintuitive design, which gets strong directionality out of thermal radiation. It's the thermal design SPHEREX went with—the space telescope that went up a few weeks ago, that was all over HN. That's: a cavity that's a thin wedge in between two slightly angled plates, where the interior surface coating is partly emissive, and partly infrared-reflective—it can reflect the thermal radiation it emits. That means specular reflections, following geometric optics, so it works like a horn for light—beams it out the sides in a narrow cone. (.pdf) https://ttu-ir.tdl.org/server/api/core/bitstreams/71aee1e9-3f65-466f-a804-2737eefd2bed/content https://ttu-ir.tdl.org/server/api/core/bitstreams/71aee1e9-3...
- tzs 2y agoHow about something like this? | __ | |_/\_| | | | \/ |__| E 1 2 3 E is the Earth. 1 is a thin lightweight black disc to block the view of the rest of the satellite. 3 is the working parts of the satellite. 2 are mirrors to direct any emissions from 1 in the direction of 3 out to the sides and to direct any emissions from 3 in the direction of 1 out to sides.
- goku12 2y agoYou should check the JWST thermal shield. It addresses exactly this problem. Also keep in mind the additional cost it incurs.
- smallnix 2y agoYes https://physicsworld.com/a/dark-coated-starlink-satellites-are-better-but-not-perfect-say-astronomers/ https://physicsworld.com/a/dark-coated-starlink-satellites-a...
- xoa 2y agoCan't tell if you're joking or not, but SpaceX has indeed been collaborating with astronomical observatories to reduce the apparent magnitude (brightness) to ground for Starlink satellites. It's not as if the potential issues weren't apparent and reported on pretty early on, ie, [0] in summer 2020 before the network entered beta. It's not perfect and the period during orbit raising before the satellites enter operational orbits is more challenging, but very significant reductions have been achieved per recs, see for example "Starlink Gen 2 Mini Satellites Photometric Characterization" [1] in 2023 and "The Brightness of Starlink Mini Satellites During Orbit-Raising" [2] in 2024: >When magnitudes are adjusted to a uniform distance of 1000 km the means are 4.58 and 7.52, respectively. The difference of 2.94 between distance-adjusted magnitudes above and below threshold implies that mitigation is 93% effective in reducing the brightness of orbit-raising spacecraft. So there has been progress, though more may be possible particularly as Starship gives them more mass to work with for less money. That may bring new possibilities to spend mass on "cosmetic" purposes to shade and further reduce magnitude even if it contributes nothing to the core functionality. Same as more mass may allow regulators to feasibly require higher levels of redundancy and more margin for deorbiting in case of issues or at EOL. Of course, that does leave older unmitigated working sats contributing to light pollution for the rest of their operational lifetimes, though worth noting that one of many major advantages for low-LEO/VLEO operation is that by design such lifetimes are much shorter, and in turn generation refresh will happen more quickly. Perhaps more importantly long term, there aren't as far as I know any actual international standards and agreements towards responsible brightness mitigation (or other issues like disposing of expended upper stages responsibly, standardized end-of-life deorbiting, etc). SpaceX has, for both PR and simple corporate self-interest reasons, been a pretty good actor so far even if they get a lot of attention for being the leading first mega constellation. But I really hope follow on efforts from other players can hit the ground running with magnitude reductions at least as good, and that SpaceX itself continues to improve (or at a bare minimum not backslide). High bandwidth fully global comms is simply too valuable a capability to really imagine going back at this point. But that's no reason not to pursue reasonable compromise mitigations, and potentially some sort of funds to ultimately create far more orbital telescopes as well as part of the package taking full advantage of what upcoming cheap megalift will make possible. ---- 0: "Impact of Satellite Constellations on Optical Astronomy and Recommendations Toward Mitigations" | https://aas.org/sites/default/files/2020-08/SATCON1-Report.pdf https://aas.org/sites/default/files/2020-08/SATCON1-Report.p... 1: https://arxiv.org/pdf/2306.06657 https://arxiv.org/pdf/2306.06657 2: https://arxiv.org/pdf/2405.12007 https://arxiv.org/pdf/2405.12007
- WalterBright 2y agoIt should also be possible to de-orbit obsolete satellites faster if they can at end-of-life deploy a "sail" that will cause more drag.
- dredmorbius 2y agoEddy-current-generating tethers seem a more practical option: <https://www.colorado.edu/faculty/kantha/sites/default/files/attached-files/carpenter.pdf https://www.colorado.edu/faculty/kantha/sites/default/files/...> (A plot point in Neal Stephenson's Seveneves.)
- youngtaff 2y agoAnd then we have to consider what’s the effect of all those vapourised metals on the atmosphere
- mr_toad 2y agoProbably not much. There’s already an estimated 48 tons of material falling into the atmosphere every day. https://science.nasa.gov/solar-system/meteors-meteorites/facts/ https://science.nasa.gov/solar-system/meteors-meteorites/fac...
- perilunar 2y agoEven better, paint it vantablack https://en.wikipedia.org/wiki/Vantablack https://en.wikipedia.org/wiki/Vantablack
- mmooss 2y agoThat would seem to remediate one problem, but they still block the view of cameras and telescopes - worse, in a way, that they might block the view without the viewer realizing they missed the occulded star.
- kofianon 2y agoA startup idea: launch satellites to capture clean night sky photos, with tiered subscription model of course.
- kibwen 2y agoStartup idea: launch anti-satellite satellites to de-orbit other satellites littering your airspace.
- luqtas 2y agoHN Startup idea: train a gen. AI on NASA photos and sell custom photos /s
- pdw 2y agoThe Kessler syndrome will take care of it
- amelius 2y agoOk, so just launch junk into space and wait.
- goku12 2y agoThere's no concept of airspace in space. You have very few avenues to keep a sat restricted to a geographic region. Orbits like geostationary and molniya exist - but they come with their own limitations for many applications.
- littlestymaar 2y agoThe concept of “airspace” is purely a legal one and exits only if your country has an air force able to enforce it (see how Israel has absolute control over Lebanese airspace), any country with anti-sattelite technology could at its disposal could declare that their airspace goes up to the geostationary orbit or even above. Of course it would complicate the use of satellites a lot, but given their military importance it's likely that this will happen at some point when the tech is ready (by tech I mean a way to stop foreign satellites from operating without causing Kessler syndrome)
- pixelesque 2y agoAs someone who co-incidentally started dabbling in Astrophotography as a hobby in early 2019 before Starlink launched, back then you literally could capture a single 20-second exposure (on a very wide lens, so no obvious star trail/blur at that focal length due to the Earth's rotation), and get images with no satellites. Now (and even in 2021 it was getting hard to do that) it's impossible to do that, even with 10 second exposures. What's needed now is multiple exposures, and merging/integrating them in something like Siril (https://siril.org/ https://siril.org/) to remove the obvious satellite trails. However, arguably, integrating multiple exposures, while annoying and time-consuming workflow-wise (i.e. can't just look at images directly from camera, and currently need to convert to TIFF first) is often the better way to get slightly-less-noisy images anyway, and integrate effectively longer exposures without star-trails, so it's a tricky one.
- genewitch 2y agoAuto stakkert I think it runs off a .mov or other video file, you add black frames, etc.
- ThrowawayTestr 2y ago[flagged]
- doodlebugging 2y ago>Unpopular opinion: global internet access is more important than pretty pictures of the sky. You're right about one thing - It is an unpopular opinion. You're wrong about global internet access being more important than being able to take "pretty pictures" of the night sky. Global internet access has become a tool for homogenizing opinion. It has become the most useful tool for propagandists and others who would push false narratives as facts in order to steer readers/listeners towards conclusions that are not based on facts. It has been subverted by well-funded groups with an agenda that does not serve the people out in the broad audience. It could've been a critical part of bringing global societies up to speed on relevant issues that affect their lives and futures. Once the deep pockets with destructive agendas began funding tools to infect others with their world-views it became a weapon, not a tool. Those of you who work in the industry should rebel against this subversion. I think many won't since the whole software industry appears to be trapped in a cycle of greedy grifts and subscriptions for worthless apps.
- transcriptase 2y agoI don’t know what the hell you’re going on about for the most part, but the fact is it’s not economically viable for ISPs or even governments to build fibre out to most rural areas. Satellite internet has been a game changer for people living in these areas. The people who grow your food deserve to be able to video chat with their family and stream videos at resolutions higher than 480p without constant buffering.
- fc417fc802 2y agoI agree that there are strong economic reasons in favor but lets not overstate things. If it was economically viable to build out copper telephone lines to those areas then there is zero reason fiber should pose an issue. As far as raw materials go fiber is much cheaper than copper.
- nntwozz 2y agoYou know those airplanes with a banner at the beach? I can imagine a constellation of satellites writing ads (live) in space using mirrors and other nifty tech. Unless regulation stops it.
- ibizaman 2y agoThat’s so true. I can see it too. The technology to make that must be super fun to work on but please I hope this will never happen. Can you imagine turning the whole sky as a giant pixelated screen to constantly show us ads? That’s as dystopian as it gets. Add to that the probable less than secure software to run it and hackers trying to show stuff up there. That’s something out of a Douglas Adams book. xD
- disconcision 2y agoearliest sci-fi antecedent i know off: https://en.wikipedia.org/wiki/The_Man_Who_Sold_the_Moon https://en.wikipedia.org/wiki/The_Man_Who_Sold_the_Moon
- blululu 2y agoThere was a Russian start up planning to do this a few years back. They had actually reached a deal with Pepsi’s Russian operations until the public backlash convinced them to find a different public relations strategy. https://phys.org/news/2019-01-astronomers-russian-billboards-space.amp https://phys.org/news/2019-01-astronomers-russian-billboards...
- jfengel 2y agoI don't think such a thing could hold together very long, unless it was just a string in a line. Maybe in Morse code? With multiple launches you could probably get several parallel strings, and use it like a dot matrix printer. It would be a heck of a stunt. But I wouldn't expect it to last for more than one orbit, and only part of the planet could see it.
- ordu 2y agoYou can change brightness and color of individual satellites as they move, so they would match the "pixel" they are in now. Just imagine swarm of very small emitting light bugs moving chaotically behind your screen and changing colors as they move from one pixel to an other. The only issue is to make sure that at every moment each pixel has enough bugs to get the required brightness.
- jfengel 2y ago"Stitching together 343 distinct photos," I don't doubt that this is a real problem for astronomers and photographers, but I feel like if you had to work that hard, it doesn't really make your case.
- threeseed 2y agoThese photos are taken in pitch-black darkness. You need to take a lot of exposures in order to get the data necessary to even see anything.
- rafram 2y agoNo, you need to take a long exposure. Multiple exposures may improve the quality but isn’t necessary at all.
- teamonkey 2y agoIf the camera is stationary you must stack multiple short exposures to avoid star trails. You can only take long exposures with an equatorial mount.
- littlestymaar 2y agoNot if your “long” exposure is just 10s long, which is enough to get those annoying starlink trails.
- teamonkey 2y agoSure, 10s is certainly long enough to capture Starlink trails, though 10s exposure is not especially long for an astro photo and you would typically want to take longer exposures or stack multiple shorter ones. For example, my Seestar S50 takes many 10-second photos to form one exposure. I would normally expect to take 1500 10-second exposures or more for a good picture, perhaps over mutiple nights (although this is very different to a wide-field image like this). A Starlink trail would be very visible in any individual frame, often brighter than stars, and I would expect to capture many individual frames containing starlink trails.
- macinjosh 2y agoIt is so polluted you need professional camera gear and processing of hundreds of photos together in order to show it. Get real. Internet access for poor, remote rural areas across the global is more important than convenient timelapse photography.
- threeseed 2y agoa) You can take these photos with a smart phone. b) In Australia we are rolling out fibre to rural areas and are testing 10Gb plans. Starlink will never come close to those speeds.
- deleted 2y ago[deleted]
- bigfatkitten 2y agoAnd you can see them with the naked eye. You don't even need to go anywhere terribly remote; there's sufficient darkness a 20 minute drive south of Canberra (population ~470,000, for those not familiar.)
- throwaway2037 2y agoI thought that the Australia National Broadband Network mostly services rural areas with microwave dishes (shortwave radio)? Are they changing their strategy? The original point of microwaves was to reduce cost of laying (fibre) cable. I tried to Google for any recent news about this roll-out that you speak of. Do you have a link that you can share?
- ezconnect 2y agoThe poor can't afford it. Military use is the only way Starlink will stay afloat.
- testing22321 2y agoYou are so far from the mark out is staggering. Starlink is priced differently in different countries, and is wildly popular in developing and undeveloped countries.
- madmask 2y agoI wonder what uncontacted tribes think about starlink
- chii 2y agowell, if you could observe these things with the naked eye, they might imagine it's similar to a passing meteor.
- mock-possum 2y agoIf I hadn’t known what starlink was the first time I saw it, I would have assumed it was something artificial - the spacing and trajectory is far too regular to be a comet breaking up or something like that.
- aaron695 2y ago[dead]
- sandspar 2y agoYou have to crack a few eggs to make an omelette. The benefits of satellites seem worth the cost, at least in the foreseeable future.
- perilunar 2y agoI’d be more concerned about the light pollution from the city (Perth?) on the horizon.
- littlestymaar 2y agoWhataboutism.
- ajxs 2y agoWould that be from Perth? Perth is around 180km away. Cervantes and Jurien Bay are nearby towns that could account for that light pollution.
- bornfreddy 2y agoI'd be more concerned about both. One evil doesn't cancel the other.
- perilunar 2y agoI'm not. I don't regard satellites as evil. While outside last night looking at the Milky Way I spotted 2 satellites and 3 aircraft. I like seeing the satellites; I dislike that I can't see the Milky Way at home in the city due to the light pollution.
- trebligdivad 2y agoThe clear grid patterns are really fantastic. (I realise that it's bad and all that - but still, those grids are amazing to see)
- 404mm 2y agoHad the same thought. In a way, that photo is absolutely stunning and beautiful in its own way. But I do understand how this is a huge problem for the astronomers.
- cyberjerkXX 2y ago[dead]
- ag56 2y agoAt no point does the article enlighten me of the actual ‘problem’. The photo is beautiful. The ability to even capture this signifies technological advancement, which I think wonderful. In some way this reminds me of living in SF back in 2015, and all the arguments over the towers going up in soma. “No one wants the Manhattanization of the city” was accepted fact on both sides. Yet that wasn’t an obvious fact to me at all, and I could never find an argument in support of this ‘fact’. Can someone enlighten me here?
- SequoiaHope 2y agoI do find the juxtaposition of “look at this image of satellites” and “the image is a composition of 360 photographs” to require a certain leap of logic that hasn’t been established. On the one hand, it shows that a lot of satellites are visible throughout the night. On the other hand it’s harder to understand what the broader implications of this are.
- asdefghyk 2y agoThe article mentions the problem .... "....Rozells’ composite visually echoes pleas from astronomers, who warn that although satellites collect essential data, the staggering amount filling our skies will only worsen light pollution and our ability to study what lies beyond. Because this industry has little regulation, the problem could go unchecked....."
- CognitiveLens 2y agoI realize it's a nit-pick, but that is not at all the common definition of light pollution as it relates to night skies.
- defrost 2y agoIt falls under clause three: What is light pollution Light Pollution is the excess or inappropriate artificial light outdoors. Light pollution occurs in three ways: glare, light trespass, and skyglow. \* Glare is the bright and uncomfortable light shining directly to the observer that interferes with your vision. \* Light trespass is the unintended spill of artificial light into other people’s property or space and often becomes a source of conflict. \* Skyglow is the brightening of the night sky from human-caused light scattered in the atmosphere. ~ https://www.nps.gov/subjects/nightskies/lightpollution.htm https://www.nps.gov/subjects/nightskies/lightpollution.htm Reflected sunlight from a human object spilling light into an environment that would otherwise not have that reflected sunlight is very much in the spirit of light pollution. It's certainly seen as such by astronomers.
- yellowapple 2y ago> Rozells’ composite visually echoes pleas from astronomers, who warn that although satellites collect essential data, the staggering amount filling our skies will only worsen light pollution and our ability to study what lies beyond. Because this industry has little regulation, the problem could go unchecked. We have the technology to put observatories in orbit, where satellite "pollution", light pollution, atmospheric effects, etc. all become significantly less problematic. Maybe that should be our focus, rather than on shaming satellite constellations for doing essential work?
- t0bia_s 2y agoArticle with misleading conclusions. Image is stacked from multiple images during sunset/sunrise when satellites are most visible because of sun position to observer. Photographer is in dark while satellites are lighted by direct sunlight. During night, its barely visible.