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Space Communications Technology

SpaceX Satellite Was On 'Collision Course' Until ESA Satellite Was Re-Routed (arstechnica.com) 65

The European Space Agency (ESA) yesterday took action to avoid a collision with a SpaceX broadband satellite after a bug in SpaceX's on-call paging system prevented the company from getting a crucial update. Ars Technica reports: "For the first time ever, ESA has performed a 'collision avoidance maneuver' to protect one of its satellites from colliding with a 'mega constellation,'" the ESA said on Twitter. The "mega constellation" ESA referred to is SpaceX's Starlink broadband system, which is in the early stages of deployment but could eventually include nearly 12,000 satellites. Action had to be taken because the ESA's Aeolus satellite and a Starlink satellite were on a course that carried more than a 1-in-10,000 chance of a collision. According to the ESA, the Earth-observation satellite Aeolus "fired its thrusters, moving it off a collision course with a SpaceX satellite in their Starlink constellation." "SpaceX explained in a statement today that it didn't initially take action because of early estimates that the risk of collision was much lower than it turned out to be," the report adds. "SpaceX said it would have coordinated with ESA to avoid a collision once the estimates got worse, if only the paging-system bug hadn't prevented SpaceX from getting an update on the collision probability. SpaceX said it is trying to fix the bug to prevent such mishaps in the future."
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SpaceX Satellite Was On 'Collision Course' Until ESA Satellite Was Re-Routed

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  • I think the predicted close approach was about a nautical mile (2-ish Km) which is not all that close, as conjunctions go. Most operators would not do anything about that.

    I suspect they did it to make a point, which seems pretty valid, about the implications of sticking huge numbers of satellites in relatively low orbits with minimal oversight/tracking. It's minimal, because it's would take inconceivable resources to track each one carefully for long periods, so the orbit knowledge wil

    • And the Starlink satellites are supposed to have autonomous collision avoidance built into them, so maybe they just said "it will take evasive action if necessary" and that wasn't a good enough answer for ESA.

    • In the article:

      SpaceX said it would have coordinated with ESA to avoid a collision once the estimates got worse, if only the paging-system bug hadn't prevented SpaceX from getting an update on the collision probability. SpaceX said it is trying to fix the bug to prevent such mishaps in the future.

      SpaceX recognised that it it was that close. And as you say:

      the orbit knowledge will be, generally, very poor by low-earth-orbit standards

      that would be a pretty valid reason for such big collision avoidance thr

      • Re:Not that close (Score:5, Interesting)

        by gnasher719 ( 869701 ) on Wednesday September 04, 2019 @05:03AM (#59156002)

        that would be a pretty valid reason for such big collision avoidance thresholds to exist

        I would assume that if you act when the chance of a hit is 1 in 10,000, you will need very little correction and spend very little fuel. If you wait longer, the danger might go away, but on the other hand there's a one in 100 chance that the risk increases to 1 in 100, and much more fuel is needed to be safe.

    • Re:Not that close (Score:5, Informative)

      by mrwireless ( 1056688 ) on Wednesday September 04, 2019 @05:50AM (#59156086)

      It does indeed feel a little political.

      This is the response by SpaceX:

      “Our Starlink team last exchanged an email with the Aeolus operations team on August 28, when the probability of collision was only in the 2.2e-5 range (or 1 in 50k), well below the 1e-4 (or 1 in 10k) industry standard threshold and 75 times lower than the final estimate. At that point, both SpaceX and ESA determined a maneuver was not necessary. Then, the U.S. Air Force’s updates showed the probability increased to 1.69e-3 (or more than 1 in 10k) but a bug in our on-call paging system prevented the Starlink operator from seeing the follow on correspondence on this probability increase – SpaceX is still investigating the issue and will implement corrective actions. However, had the Starlink operator seen the correspondence, we would have coordinated with ESA to determine best approach with their continuing with their maneuver or our performing a maneuver.”

      More interestingly, ESA contradicted themselves by tweeting that this type of maneuver happens about once every two weeks:

      "In 2018, ESA performed 28 #collisionavoidance manoeuvres across its fleet. See for example a 2018 manoeuvre by @ESA_Cryosat: https://t.co/vWtufIY4ii [t.co]"
      — ESA Operations (@esaoperations) September 2, 2019

      Finally, Matt Desch, CEO of Iridium, the satellite telephony company, tweeted this:

      "Hmmm. We move our satellites on average once a week and don't put out a press release to say who we maneuvered around https://t.co/L4XyoQVydP [t.co]"

      Source:
      https://www.teslarati.com/spac... [teslarati.com]

      • Re:Not that close (Score:4, Informative)

        by Anonyme Connard ( 218057 ) on Wednesday September 04, 2019 @08:49AM (#59156498)

        These weekly moves are because of space debris. This was the first time ESA had to do this to avoid another satellite.

        • Makes no difference if you hit debris or another satellite. At those speeds, you don't need the thing you hit to have that much mass for it to be a major disaster for your spacecraft.
          • Of course, and that is the reason for these manoeuvres.
            I was just explaining the rationnal of the press release and that ESA did not contradict itself.

      • Re: Not that close (Score:5, Interesting)

        by ToasterMonkey ( 467067 ) on Wednesday September 04, 2019 @10:07AM (#59156856) Homepage

        Did you catch the part where a satellite fleet is being monitored by a person on pager duty, and the paging software messed up, leaving them out of the loop after the initial alert and making them appear unresponsive when the condition got more serious?

        Can you imagine automated trains heading towards each other with a few switches between them still... on Mars to make it fun, and one side having to take evasive actions because - apparently - the operator of the other side went back to sleep after the initial exchange? They may as well be if they stopped getting communications from the pager system.

        You can't tell me this Iridium guy quoted here doesn't have butts-in-chairs-on-phones in some kind of operations or command center somewhere.

        • You can't tell me this Iridium guy quoted here doesn't have butts-in-chairs-on-phones in some kind of operations or command center somewhere.

          Iridium guy definitely does, because the assets he's protecting are individually enormously expensive.

          SpaceX would regret the loss of a satellite in a collision with random junk, but they would simply move on. (Obviously they would really regret colliding with someone else's expensive satellite.) When you have thousands in orbit, as they will, plus or minus one satellite simply isn't that big a deal compared to Iridium. Iridium cares, enormously. They have to. If they lose a bird, they're down 2% of th

    • It takes inconceivable resources to track large numbers of satellites for long periods of time? How many slide rules would it take?

      • 12,000 of them? Several.

            Figure it takes at least two live (ranging transponder) observations for about 5 minutes every few days, then multiply by 12,000.

    • It's not just the distance, it's the uncertainty. The less tracking you have, the more uncertain you are. That's why, like TFA shows, we make these decisions based on probability, not distance.
    • I think the predicted close approach was about a nautical mile (2-ish Km) which is not all that close, as conjunctions go.

      2 km at an orbital velocity of 25,000 kph (low earth orbit) is about 0.29 seconds. Granted that's absolute velocity, not relative. But they're highly inclined (orbit is tilted relative to the equator) - 50 to 80 degrees. The ESA satellites are earth-observing so tend to be in polar orbits (90 degree inclination). So depending on the inclination and phase of the two satellites, the

  • by PolygamousRanchKid ( 1290638 ) on Wednesday September 04, 2019 @05:07AM (#59156006)

    In the US, there are local TV ads where lawyers say:

    "Have you or anyone related to you been injured in a car accident that was not your fault? We can help you get proper compensation!"

    So soon we will be seeing ads like:

    "Have you or anyone related to you been injured in a satellite collision that was not your fault? We can help you get proper compensation!"

    Do satellites have dash-cams these days . . . ? That would be useful in proving fault:

    "Hey, that other satellite was texting while flying through space!

  • by Viol8 ( 599362 ) on Wednesday September 04, 2019 @05:09AM (#59156018) Homepage

    ... until people in power wake up and realise that launching endless junk into earth orbit that is primarily designed to increase a companies profits rather than provide anything fundamentally useful is only going to end in tears when the amount up there reaches a critical mass and ends up making various orbits unusable and launching into space even more dangerous.

    Perhaps in 50 years this obscene trashing of this useful resource will be seen in the same light as plastic pollution in the oceans or similar.

    • by JaredOfEuropa ( 526365 ) on Wednesday September 04, 2019 @05:12AM (#59156024) Journal

      increase a companies profits rather than provide anything fundamentally useful

      How is the company to profit if the satellites do not provide anything useful?

      • by fazig ( 2909523 ) on Wednesday September 04, 2019 @05:40AM (#59156074)
        Well, technically you do not have to provide something useful to make a profit.
        See solar roadways in France for example. It's a failure, but you can be sure the contractors that built it made a nice little profit.
        • by Freischutz ( 4776131 ) on Wednesday September 04, 2019 @06:02AM (#59156104)

          Well, technically you do not have to provide something useful to make a profit. See solar roadways in France for example. It's a failure, but you can be sure the contractors that built it made a nice little profit.

          Same for the US wars in the Middle East and Central Asia. Complete omnishambles but the arms industry is thriving.

          • Don't forget endless welfare. People still starving but politicians making a killing on "donations" to their "nonprofit" political committees.

            • Don't forget endless welfare. People still starving but politicians making a killing on "donations" to their "nonprofit" political committees.

              Yeah, much as the right wing likes to complain about welfare they sure as hell enjoy lining their pockets by driving up the prices of stuff like insulin to the point where 30 dollars will buy you the same amount in Canada as 320 dollars in the US. If anybody is getting fat off the welfare and healthcare systems it's not the people using those systems it's the business mafia that habitually votes Republican and ceaselessly rages on about the evils of welfare and universal healthcare.

          • They look like type 1 clusterfucks until you realize that the goal is to keep the oil flowing away from our enemies, and not to ever actually solve any problems in the region. Same reason we back Israel. It's not because we give one fuck about Jews, as a nation anyway. We ignored reports of the Holocaust and sent fuel to Hitler's S.S. and aluminum to Japan to be made into Mitsubishi zeroes, we give not one fuck about the Israelites. But we do care a whole bunch about the world's fastest-growing religion, an

            • by Shotgun ( 30919 )

              How is Israel, a nation that I could walk across in a day, suppressing the world's fastest-growing religion? Especially considering that they literally have people who practice that religion as part of their government.

              • How is Israel, a nation that I could walk across in a day
                In which direction? North to south? East to West? At which latitude?
                Are you sure you can carry enough water to walk through Negev?
                Sigh sigh sigh, kids in our days.

              • How is Israel, a nation that I could walk across in a day, suppressing the world's fastest-growing religion?

                Imagine how bold they'll be if they hold the "holy city".

                TL;DR: nukes

        • The contractors who build the solar roadway made a profit because they successfully fulfilled the request of the person/company/organization/government who wanted the roadway built. That the road failed is entirely the fault of the person/company/organization/government who thought it would be a good (profitable) idea. The concept of a contract to specify work to be performed and being paid for the job, was developed to prevent the type of blame-shifting you're doing. If the contractors fulfilled the let
          • by fazig ( 2909523 )
            So to reiterate: A lot of people did their job, a lot of people got paid and made a profit, but still the end-product is useless.
            I'm not debating whose fault it is that the end-product is useless, just that it being useful is not a necessity for profit one one side. There was a lot of profit, just not for customer, the French Government. And there was no fraud or theft, except perhaps on the side of the people who managed to convince the government it was a good idea.

            Also a lot of businesses stick with b
      • by ledow ( 319597 )

        Why does the company need to profit?

        Tesla launched a fecking CAR into space just for the hell of it.

        • by DrYak ( 748999 )

          Tesla launched a fecking CAR into space just for the hell of it.

          when doing test flights, you need some weight (dummy payload) to simulate the presence of the actual payloads (sattelites or whatever) in the following real missions.

          - the car served the purpose of a dummy payload.

          SpaceX of course will select funny or silly dummy payload [space.com] for the attention it might attract.

          - the car also served marketing purposes.

      • by Viol8 ( 599362 ) on Wednesday September 04, 2019 @06:19AM (#59156134) Homepage

        Anything useful for the vast majority of humanity then, rather than a nice-to-have toy.

        • Most people benefit from communication, which is a major satellite application.

          • by Viol8 ( 599362 )

            Sure - if the world wasn't already so well covered with cellphone masts that they even use them in the african deserts. Other than for shipping and aviation which are already catered for there is little reason for yet another satellite phone constellation.

            • Sure - if the world wasn't already so well covered with cellphone masts that they even use them in the african deserts. Other than for shipping and aviation which are already catered for there is little reason for yet another satellite phone constellation.

              Not phone. High bandwidth, low latency data via satellite.

        • Anything useful for the vast majority of humanity then, rather than a nice-to-have toy.

          You mean the internet? Starlink is an ISP (or will be if it succeeds).

    • Wrong. SpaceX is doing this out of the goodness of their hearts in order to take us all to Mars (and beyond). Don't you want to leave this rock stuck in a gravity well?

    • Perhaps in 50 years this obscene trashing of this useful resource will be seen in the same light as plastic pollution in the oceans or similar.

      There's a big difference between oceans and *low* earth orbit.

      Dumping currently-considered-indestructible plastics in the ocean: its going to stay there for quite some time, at least until some bacteria has successfully evolved into using it as an energy source and degrade it. (it's happening, it's just slow. You'll probably need a bit more than 50years).

      Loading stuff in *low* earth orbit: at this short distance from earth, there's a tiny bit of drag. Without any attitude correction, eventually everything w

      • Thay's part of the reasons why ISS is parked there (less space debris in orbit there and thus lower collision risks).

        That's a small part. The two bigger reasons are lifting capability of things that need to get there (mainly Soyuz and Space Shuttle at the time it was built), and radiation - staying well below the Van Allen belt so in high solar times you don't overly irradiate the Astronauts.

    • That will be just in time to test the US Space Force's orbit-clearing superweapon.
    • by AHuxley ( 892839 )
      Who has the power of a space force behind them?
      USA? EU? Germany? France with extra Ada?
      "We change orbit for nobody"
    • I wonder how long it'll be... ...until people in power wake up and realise that launching endless junk into earth orbit that is primarily designed to increase a companies profits rather than provide anything fundamentally useful is only going to end in tears when the amount up there reaches a critical mass and ends up making various orbits unusable and launching into space even more dangerous.

      ...until people stop breaking breaking their sentences in the subject line.

      or ...until innumerate people stop concern trolling about "space junk" when they have no understanding at all of the size of useful Earth orbit, the natural longevity of even unpowered debris in low Earth orbit, or any clue about how to use space debris flux modeling [colorado.edu] equations to understand anything.

      And one other thing. There is a single solution to Kessler Syndrome. It is expensive but it is entirely physically possible. It's cal

  • Any old excuse for a Musk Bad headline.

    • by hackertourist ( 2202674 ) on Wednesday September 04, 2019 @08:01AM (#59156366)

      1 in 10K and 1 km (+/- an uncertainty) away from a satellite that cost $500M. And a collision would generate tens of thousands of pieces of debris, bringing the next collision that much closer.

      The point is, SpaceX messed up by having showstopper bugs in their collision avoidance procedure, making it clear they didn't test this before they started launching satellites. ESA's right to be cranky.

      • And a collision would generate tens of thousands of pieces of debris, bringing the next collision that much closer.

        Once each tech billionaire has finished deploying their own personal ego-boosting mega constellation of communications satellites, LEO is going to look like the setups you see when you search for "mousetrap ping pong balls" on YouTube.

    • by Salgak1 ( 20136 )

      If he only had a spray tan . . .

      Then it would be Orange Musk Bad. . . .

      ( grinning madly, diving for cover )

  • Sounds like a lame excuse from SpaceX ... they should have to pay for this.

  • A tractor trailer on I95 Southbound switched lanes and avoided a peice of debris in the road.

    50 years from now we will laugh at this nothing happened news.

  • Surely collision avoidance is a "critical system" for satellites, and so an emergency (or even routine) order to change course should have been tested to the extreme. Am I missing something here, or does this paint as bleak a picture of SpaceX as I'm seeing - one where absolutely vital systems are put into operation without having been fully tested?

    "Oh, sorry, we've created an unstoppable satellite collision cascade that changes life on earth as we know it for the next 100 years. Our bad, we outsourced that

    • by DrYak ( 748999 )

      Or am I overreacting here?

      A tiny bit....

      Oh, sorry, we've created an unstoppable satellite collision cascade that changes life on earth as we know it for the next 100 years.

      except that in worst case scenario it would take about a decade or so before everything is squeaky clean again, due to the tiny drag that is still there at that distance and cuases everything to deorbit un assisted.

      but yeah in general it would be a good idea to avoid creating a big mess above, just due to problems in the procedure regarding collision risks.

      even more so as Starlink is the first massive communication constellation, but definitely not the last one.

      it will probably go the same way

      • by Hodr ( 219920 )

        except that in worst case scenario it would take about a decade or so before everything is squeaky clean again, due to the tiny drag that is still there at that distance and cuases everything to deorbit un assisted.

        Where did you get that idea?

        Starlink satellites operate at 550km, and while they are programmed to de-orbit automatically, the worst case would be a failure of this system (which may be likely if they are struck and become orbiting debris).

        The satellites themselves might be designed to have enough drag even without a deployed de-orbit sail to come down in a decade (this isn't indicated in their press releases as far as I can see), but in the event of a collision you would certainly have debris separated fro

        • by Shotgun ( 30919 )

          Drag from the solar wind is not inconsequential, and the drag as it approaches the sun will always be greater than when it moves away. This will both slow down the debris and perturb the orbit. A perturbed orbit will force the debris to dip lower, where it will encounter more drag from the denser atmosphere. The orbit decay will be exponential.

        • Yes, Starlink birds are deliberately high-drag. Don't remember where I saw it, though.
  • Yeah, right. The driver was probably asleep.

  • It was a pedo, wasn't it Elon??

  • The ESA satellite had a Tesla door lock mechanism, and the recent app update resulted in them being locked out for a few hours...
  • My car was headed directly for a tree..... Until I re-rerouted it.
  • by Tomahawk ( 1343 )

    They had to avoid *one* satellite that was at a much lower altitude than the constellation. This satellite is flying flow as it appears SpaceX are going to deorbit it soon.

    They were never anywhere near the "constellation".

    Also, ESA and SpaceX *had* been discussing this earlier, when the calculated risk factor was much lower, and had decided no action was required. It was a later call, when the risk was re-evaluated and increased, that was missed due to a bug in SpaceX's system.

    ESA is blowing this waaaay o

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