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posted by Fnord666 on Saturday April 25 2020, @08:32AM   Printer-friendly
from the shining-star dept.

Source: Musk says SpaceX is 'fixing' brightness from satellites:

Stargazers around the world and including many Britons have witnessed unusual constellations made up of the low earth orbit spacecraft.

SpaceX has been launching large batches of satellites as part of its Starlink project to improve global internet coverage.

The most recent launch took place on Wednesday.

Responding to a question about the brightness of the Starlink satellites on Twitter, Mr Musk said it was due to the angle of the satellites solar panels and the company was "fixing it now".

A fix could make them less visible from Earth.


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  • (Score: 1, Interesting) by Anonymous Coward on Saturday April 25 2020, @12:09PM (15 children)

    by Anonymous Coward on Saturday April 25 2020, @12:09PM (#986892)

    The distance is much closer than GeoSyncSats. The radio tech has improved and the phased array antenna panels should make for good results. I think the biggest problem will be the routing time slots being much shorter than other systems. The packet path will be switching paths on the order of minutes or even seconds. That's for each station too not just subnets.

    I worry more about a second Eternal September trashing what's left of the smart parts of the internet. What is needed is a vetted SCIENCE internet.
    One where reading is free but postings is only for vetted and verified scientist (and only on science subjects.)

    Thanks...

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  • (Score: 0) by Anonymous Coward on Saturday April 25 2020, @12:33PM

    by Anonymous Coward on Saturday April 25 2020, @12:33PM (#986899)

    Couldn't you just set up a private forum or something?

  • (Score: 2) by takyon on Saturday April 25 2020, @12:37PM

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Saturday April 25 2020, @12:37PM (#986902) Journal

    I worry more about a second Eternal September trashing what's left of the smart parts of the internet.

    Oh no, the Africans are coming!

    If you want to prevent a second Eternal September, you need to ban anonymous comments and any users that step out of line. Then remove Unicode support to get rid of foreign languages and emojispeak.

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  • (Score: 2) by quietus on Saturday April 25 2020, @01:21PM (7 children)

    by quietus (6328) on Saturday April 25 2020, @01:21PM (#986926) Journal

    I think the biggest problem will be the routing time slots being much shorter than other systems. The packet path will be switching paths on the order of minutes or even seconds. That's for each station too not just subnets.

    I am flabbergasted. Genuine troll, or just escaped from the asylum?

    • (Score: 2) by deimtee on Saturday April 25 2020, @04:17PM (6 children)

      by deimtee (3272) on Saturday April 25 2020, @04:17PM (#986989) Journal

      Seconds is bullshit, but for a satellite at 500 km it is not that many minutes to go from horizon to horizon. Assuming say a maximum angle of 45 degrees, you would indeed be switching satellites every few minutes. If their protocols are good, this shouldn't be a problem.

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      • (Score: 1, Troll) by All Your Lawn Are Belong To Us on Saturday April 25 2020, @05:41PM (5 children)

        by All Your Lawn Are Belong To Us (6553) on Saturday April 25 2020, @05:41PM (#987029) Journal

        Uh... these aren't geosynchronous? (I'm sorry to say I haven't checked). If not, this becomes the most stupid plan I think I've heard of.

        If they are geosynchonous, then as long as you are at a fixed position you should basically always be communicating on the same satellite. (Yeah, mobile users might vary). And then it is still the stupidest plan I think I've ever heard of.

        I don't care how well they fix it, if the solar angle is correct it will be visible when doing astrophotography. And lots of astronomers protested SpaceX's plans to do this, but nobody who had the power told them, "no, you can't," or even really addressed the subject that I'm aware of. Though I would like to be proven wrong.

        All because people needing teh Internets is more important than the science that developed the technology to do it.

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        This sig for rent.
        • (Score: 3, Informative) by takyon on Saturday April 25 2020, @08:08PM (4 children)

          by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Saturday April 25 2020, @08:08PM (#987081) Journal

          Yeah, you might need to freshen up on what's going on before you call it stupid.

          https://en.wikipedia.org/wiki/Starlink [wikipedia.org]

          The satellites will employ optical inter-satellite links and phased array beam-forming and digital processing technologies in the Ku and Ka bands, according to documents filed with the U.S. Federal Communications Commission (FCC). While specifics of the phased array technologies have been disclosed as part of the frequency application, SpaceX enforced confidentiality regarding details of the optical inter-satellite links. Early satellites are launched without laser links, in October 2019 SpaceX expected satellites with these links to be ready by the end of 2020.

          [...] Internet traffic via a geostationary satellite has a minimum theoretical round-trip latency of at least 477 ms (between user and ground gateway), but in practice, current satellites have latencies of 600 ms or more. Starlink satellites would orbit at ​1⁄30 to ​1⁄105 of the height of geostationary orbits, and thus offer more practical Earth-to-sat latencies of around 25 to 35 ms, comparable to existing cable and fiber networks.

          [...] The system will not directly connect from its satellites to handsets (unlike the constellations from Iridium, Globalstar, Thuraya and Inmarsat). Instead, it will be linked to flat user terminals the size of a pizza box, which will have phased array antennas and track the satellites. The terminals can be mounted anywhere, as long as they can see the sky.

          In 2019, tests by the U.S. Air Force Research Laboratory (AFRL) demonstrated a 610 megabit per second data link through Starlink to a Beechcraft C-12 Huron aircraft in flight.

          [...] SpaceX representatives and Musk have claimed that the satellites will have minimal impact. Many professional astronomers have disputed these claims based on initial observation of the Starlink v0.9 satellites on the first launch, shortly after their deployment from the launch vehicle. In later statements on Twitter, Musk stated that SpaceX will work on reducing the albedo of the satellites and will provide on-demand orientation adjustments for astronomical experiments, if necessary. To date, only one Starlink satellite (Starlink 1130-Darksat) has experimental coating to reduce its albedo. However the reduction in magnitude is very subtle with only 0.8 magnitude reduction, and this is not sufficient for astronomers.

          "Beyond this (darkening) treatment, SpaceX is developing new mitigation efforts that it plans to test in the coming months", SpaceX wrote in Federal Communications Commission (FCC) filing, on 17 April 2020. "Additionally, SpaceX will make satellite tracking data available so astronomers can better coordinate their observations with our satellites". Another change from SpaceX is studying the addition of a sunshade, or visor, to unfurl like an umbrella on Starlink satellites to reduce the amount of sunlight glinting off the spacecraft. Musk tweeted Wednesday that SpaceX is taking "key steps to reduce satellite brightness". He wrote that the satellites "should be much less noticeable" when they are flying at lower altitudes soon after launch. SpaceX is changing the angle of each satellite's solar panel, and all of the Starlink satellites will have sunshades beginning with the ninth launch of the fleet. That launch is expected in a couple of months.

          LEO is where you want it, not GEO, user terminals can track multiple overhead satellites, and they are working on reducing the visibility of the satellites. The FCC approved of Starlink. Astronomers need to face the reality of significant human activity in space, and they can embrace it by launching superior space telescopes (soon to be very cheaply launched by SpaceX).

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          • (Score: 2) by All Your Lawn Are Belong To Us on Wednesday April 29 2020, @10:34PM (3 children)

            by All Your Lawn Are Belong To Us (6553) on Wednesday April 29 2020, @10:34PM (#988348) Journal

            Maybe they should have solved those problems before they launched? And "astronomer" does not necessarily mean "educational facility that has invested millions of dollars in a meters-long aperture." If they give me an 800 number I can call so that it won't interfere with my astrophotography, great! Otherwise, as I said, and as the article said, they haven't walked the walk yet.

            Though I do find it interesting to be currently modded +1 Troll.

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            • (Score: 2) by takyon on Wednesday April 29 2020, @11:06PM (2 children)

              by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Wednesday April 29 2020, @11:06PM (#988355) Journal

              I didn't mod it, but complaining about single downmods is so 2-4 years ago.

              They have launched only a small fraction of the planned constellation. And the next launch (May 7) and subsequent launches will include what could be the last solution they will come up with for reducing the brightness:

              https://spacenews.com/spacex-to-test-starlink-sun-visor-to-reduce-brightness/ [spacenews.com]
              https://techcrunch.com/2020/04/28/elon-musk-provides-more-details-about-spacexs-plan-to-reduce-starlink-satellite-visibility/ [techcrunch.com]
              https://en.wikipedia.org/wiki/Starlink#List_of_launches [wikipedia.org]

              The smaller astronomers matter even less than the institutions. But the sats should be invisible to the naked eye, and we'll see how well the "visors" work for astrophotography.

              800 number? If there is something like that, it will be a website or tracking software.

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              • (Score: 2) by All Your Lawn Are Belong To Us on Thursday April 30 2020, @04:53PM (1 child)

                by All Your Lawn Are Belong To Us (6553) on Thursday April 30 2020, @04:53PM (#988638) Journal

                Wasn't complaining about the mod. Just noting the irony as I think that's the first time I've seen any post of mine, anon or not, as a Troll-but-positive rating. Sorry if I implied or jumped to the conclusion that you were the downmodder, as you were just disagreeing with me.

                It would have been nice if they had addressed the issue pre-launch, and if they did but what they planned failed that was fine. But my understanding is they were cautioned well in advance of this but went ahead anyway.

                But there is a world of gray as to what constitutes 'small' versus 'large'. I've only got about three grand in my setup, and I am indeed small time. But I can stick up for what I have. I know clubs and astronomers who have invested tens of thousands, participate in research projects in affiliation with larger centers, and they are still considered small. Astronomy is still one of those fields where amateurs can make significant contributions to the field.

                But yes, I think littering the skies with thousands of satellites to provide internet access to the public is a colossal waste, capable of being better supplied by ground-bound means with far better latency, and I do sincerely hope Starlink falls flat on its face. Which is bittersweet, as I do wish them success with their Mars project.

                But there are better ways to accomplish this. Hughes provides nationwide internet coverage with EchoStar using 9 current satellites including some from other providers, and they have launched a total of 24 satellites since 1995. One does not need thousands of satellites to establish worldwide internet coverage.

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                • (Score: 2) by takyon on Friday May 01 2020, @12:13AM

                  by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday May 01 2020, @12:13AM (#988771) Journal

                  You aren't an OG until you've achieved the elusive (Score: 5, Troll).

                  Starlink (low Earth orbit broadband) is the superior internet option for anyone off the grid, or in an aircraft [spacenews.com], boat, RV, etc. No digging anything up or maintaining cables. Very good for a nomadic or mobile lifestyle, or homes that ISPs refuse to connect to. When thinking about deployment, you should look at Australia's National Broadband Network [wikipedia.org]. Lots of rural people to connect, broken promises [theregister.co.uk] of high speed fiber, high costs, etc. It's no surprise that Australia is the second country to take steps towards approval of Starlink [cnbc.com].

                  Geostationary satellites mean very high latency, making it unsuitable for many applications. A limited number of satellites means low total bandwidth, and less speed per customer. LEO broadband is probably less susceptible to weather conditions.

                  Starlink could have superior latency to ground-based in certain scenarios. For example, communicating between New York and London.

                  LEO satellites are easier to launch, and if something goes wrong, they can be passively deorbited.

                  Starlink isn't the only player in this. OneWeb is out for now, but Amazon/Blue Origin intends to have their own constellation, and there will likely be a Chinese constellation down the line. Broadband sats aren't the only "junk" you can expect in LEO. And part of that will be a consequence of the cheap fully reusable Starship being developed for SpaceX's "Mars project". Getting stuff into low Earth orbit will become 90% cheaper, perhaps 99% cheaper.

                  Starlink satellites have mandated deorbit plans, so any early prototypes that are too bright are going to be gone within about 6 years. Maybe sooner if they decide to deorbit them early. The "trains" of satellites that have been spotted by astronomers shortly after launches aren't representative of the final orbits and brightness anyway (and they spread out).

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  • (Score: 3, Insightful) by maxwell demon on Sunday April 26 2020, @08:59AM (4 children)

    by maxwell demon (1608) on Sunday April 26 2020, @08:59AM (#987226) Journal

    The distance is much closer than GeoSyncSats.

    All the rain is below the orbit of all satellites, therefore the effect of rain should be independent on whether they are in GEO or in LEO.

    --
    The Tao of math: The numbers you can count are not the real numbers.
    • (Score: 2) by Muad'Dave on Monday April 27 2020, @03:30PM (3 children)

      by Muad'Dave (1413) on Monday April 27 2020, @03:30PM (#987546)

      You're not taking total path loss into account when adding in the effect of rain fade. The base stations and sats have a fixed amount much power and antenna gain.

      The free space path loss [pasternack.com] for a 550 km orbit at 24 GHz is 175 dB. The FSPL to geosync (35,786 km) is a staggering 211 dB. That's 36 dB - a factor of 4000.

      Rain fade at 24 GHz [ui.com] can be as little as 0.2 dB/km for light rain and as much as 4 dB/km for a real frog-strangler. The troposphere is about 10 km thick, so we're looking at 2-40 dB attenuation from rain. A heavy rain is approximately the the same amount of attenuation as increasing the orbit from 550 km to geosync.

      If the link budget has < 40 dB available, then at geosync the rain will kill the connection.

      • (Score: 2) by maxwell demon on Tuesday April 28 2020, @06:47AM (2 children)

        by maxwell demon (1608) on Tuesday April 28 2020, @06:47AM (#987740) Journal

        You're not taking the intelligence of the system designers into account. GEO communication will occur at higher power than LEO communication, exactly because GEO satellites are higher up. Or in short, a system designed for the same performance/reliability will have higher sending power and/or more sensitive receivers in GEO vs. LEO.

        Therefore the effect of rain will reduce the actually received signal by the exact same amount.

        --
        The Tao of math: The numbers you can count are not the real numbers.
        • (Score: 2) by Muad'Dave on Tuesday April 28 2020, @11:04AM (1 child)

          by Muad'Dave (1413) on Tuesday April 28 2020, @11:04AM (#987779)

          I understand engineering link budgets for RF systems, and I never said the absolute rain fade was anything but exactly equal in both cases. What I did say was that _for the given antenna size and power levels_, the additional loss to geosync would likely push the existing budget past its limits (and perhaps past technological limits, i.e. noise floor or SNR).

          • (Score: 2) by maxwell demon on Tuesday April 28 2020, @02:56PM

            by maxwell demon (1608) on Tuesday April 28 2020, @02:56PM (#987835) Journal

            No one is going to take a satellite designed for LEO and put it into GEO. And at least GEO to ground during rain doesn't exceed physical limits, as my satellite TV reception proves.

            --
            The Tao of math: The numbers you can count are not the real numbers.