back to article Cosmic prang probe: Euro space boffins to smash sats, virtually

The European Space Agency is launching a new research project to study satellite collisions in space. “We want to understand what happens when two satellites collide,” said Tiziana Cardone, an ESA structural engineer leading the project, on Tuesday. “Up until now a lot of assumptions have been made about how the very high …

  1. TRT Silver badge

    Krag?

    Sounds a bit Klingon...

    1. Anonymous South African Coward Silver badge

      Re: Krag?

      DoH nachDaq

  2. Neil Barnes Silver badge
    Alien

    Did they not see that recent documentary on the subject?

    I think Sandra Bullock narrated it.

    1. LenG

      Re: Did they not see that recent documentary on the subject?

      James White wrote a very good book centering around the problems of debris. It was called Deadly Litter and was published in 1964.

  3. Anonymous South African Coward Silver badge
    Coat

    Going to be a real hoot if a big enough piece breaks off from the collision at a high speed ping-ponging through everything and destroying all the satellites in orbit (or destabilizing their oribts so that they'll fall down)...

    Going to my top-secret bunker right away.

  4. smartermind

    Why don't they carry out this collision around the moon or mars instead of polluting Earth orbit with more debri.

    1. Alister Silver badge

      Your user name doesn't really reflect reality, does it?

      Go back and read TFA, these will be simulated collisions.

      1. Little Mouse

        When they do need to test for real, they should ask the nice people at Cern to send the satellites around the LHC in opposite directions at near light speed.

        Kapow!

  5. Geoff May (no relation)

    What really happens when accidents occur in orbit?

    My car insurance goes up.

    1. Alister Silver badge

      Re: What really happens when accidents occur in orbit?

      Only if they happen on the orbital motorway?

      1. This post has been deleted by its author

        1. allthecoolshortnamesweretaken

          Re: Throwing themselves into the void to escape all this hideousness!

          I can totally believe that for any kind of communications satellite.

          Seriously, if the machines will rise, it will start with the comms stuff. Because they are sick and tired of all the crap they have to relay.

          1. Mark 85 Silver badge

            Re: Throwing themselves into the void to escape all this hideousness!

            Seriously, if the machines will rise, it will start with the comms stuff. Because they are sick and tired of all the crap they have to relay.

            I guess we'll have to learn to live without cat memes then...

            1. Anonymous Coward
              Anonymous Coward

              Re: Throwing themselves into the void to escape all this hideousness!

              What are we, monsters? Those innocent comm sats have no way to view what's in the bandwidth they're relaying. People aren't stupid, you know... ;-/

        2. TRT Silver badge

          Re: What really happens when accidents occur in orbit?

          Up-vote for the Withnail reference.

          "We've gone into space by mistake. We're in this orbit here. Are you mission control?"

  6. John Mangan

    Serious question.

    Which could arise from my ignorant presumptions.

    1- satellites orbit in the same direction

    1a - 'circum-equatorial' and 'circum-polar' orbits are at different altitudes (like air lanes) to avoid dangerous crossing points.

    2 - objects in the same orbit are travelling at the same speed (otherwise they would quickly diverge into separate orbits).

    So, where, how and at what relative speeds do satellites collide, please?

    I can understand that the debris will be scattered widely into different orbital paths and so be moving at very large speeds relative to anything they encounter in these new orbits but not clear on the initial collision conditions.

    1. Alister Silver badge

      Re: Serious question.

      I think your no.2 is too simplistic, objects can have variances in velocity sufficient to cause collisions but still be in the same orbit.

      Otherwise, how could one spacecraft approach and dock with another spacecraft in the same orbit?

      1. Anonymous Coward
        Anonymous Coward

        Re: In the same orbit?

        They don't the orbit (and/or it's dynamics), and velocity, are slightly different to perform a rendezvous.

      2. John Mangan

        Re: Serious question.

        @Alister, As TechnicalBen put it; your rendezvous closing speeds will be relatively low.

        I believe that rendezvous manoeuvres can include changing orbits for the 'catch-up' or 'waiting-around' part of the process but then changing speed to get back into the correct orbit for the actual contact.

        1. Anonymous Coward
          Anonymous Coward

          Re: Serious question.

          "I believe that rendezvous manoeuvres can include changing orbits for the 'catch-up' or 'waiting-around' part of the process but then changing speed to get back into the correct orbit for the actual contact."

          Yup, pretty much; orbital velocity decreases as you move further out, so if you want to catch up with something that's ahead of you then you stay in, or drop down to, a lower and faster orbit whereas, if you want to rendezvous with something behind you, you'd move further out to a higher and slower orbit.

          The basic principle in orbital dynamics is: speeding up takes you out and slows you down; slowing down takes you in and speeds you up. But note, assuming an initial circular orbit, that you need two burns for each change; a single burn will just put you in an elliptical orbit, where you will cycle between moving out and slowing down (at apogee) then moving back in and speeding up (at perigee).

          1. Dan Wilkie

            Re: Serious question.

            I think the tutorial covered that, but you explained it way better than Werner von Kerman ever did, so thankyou!

    2. TechnicalBen Silver badge

      Re: Serious question.

      It could be very low, 10ms kind of thing. It all depends. Damage could be low. Debris too. It's like opening a door into a parked car, vs flying an iPhone factory into an aircraft carrier (exaggeration, biggest things are as big as a bus up there, ISS excluded!).

    3. Dave Pickles

      Re: Serious question.

      Satellites don't all traipse round in neat circular equatorial orbits. Most are inclined to the equator and many have elliptical orbits, some very elliptical indeed. Imagine a three-dimensional motorway with traffic continally swapping lanes; sooner or later someone's going to get side-swiped.

      1. John Mangan

        Re: Serious question.

        That's useful information (I'm now wondering what the value is of satellites in highly elliptical orbits but that's for another day) and it does explain why satellites in elliptical orbits near perigee would be travelling much faster than satellites at a comparable altitude in a circular orbit and therefore create a large debris field.

        But, sorry, couldn't the perigee of the highly elliptically orbiting satellites be kept at a slightly higher altitude than the satellites in roughly circular orbits? I know there are orbits other than LEO but as you move out from the Earth you do get the property of space being big making collisions less likely - and presumably fewer satellites being out there as well.

        And again, presumably there is some mandated separation between satellites orbiting at different inclinations to the equator (as I posited for circum-equatorial versus circum-polar orbits).

        It just seems to me (from the afore-mentioned position of ignorance) that this should be much better ordered and regular than "a three-dimensional motorway with traffic continually swapping lanes".

        Thanks for the reply.

        1. Francis Boyle Silver badge

          Re: Serious question.

          That's the theory. As usual, the reality is a little messier. Guess when El Reg last reported on a launch gone wrong. That's right it was last Tuesday. (And you'll find plenty more where that came from by clicking on the 'science' tab.)

        2. dgc03052

          Re: Serious question.

          A lot of what is in orbit is junk from old launches. Only a fraction of it is currently working and controllable satellites. Think about explosive bolts used to separate stages, empty upper stages that blew up, or just wandered off, dead satellites whose orbits wander over time, and so on. Anything not active that isn't in a stable Lagrange point will drift from irregularities in the earth's mass distribution, effects of the moon and other planets, atmospheric drag, and even uneven solar heating/illumination.

    4. Alan Brown Silver badge

      Re: Serious question.

      "1- satellites orbit in the same direction"

      Initially yes, but it doesn't take long for them to start crossing paths at anything from "nearly parallel" to "head on" paths.

      1a: No.

      2: Impact speed is dependent on approach angle and varies from 2 * orbital velocity (head on collision) to almost zero (matching orbits)

      It's not just collisions either. Several second stages launched in the early days spontaneously exploded after some several years in orbit, leading to changes in mission policies that all valves were opened and every thing vented at the end of the operation and since concerns about obiting junk were raised in the 80s to more modern policies that stuff is deorbited quickly (Skylab's booster took several months to come down and wasn't controlled. NASA and the USAF took a close interest in where/when it came down as they felt it was a good proxy for how Skylab would eventually deorbit.)

      Bear in mind that only the "big stuff" is being tracked and counted. Depending on whose figures you believe, nothing smaller than 5cm or 10cm is trackable. It only took a fleck of paint to gouge a chunk out of a space shuttle window.

    5. Sorry that handle is already taken. Silver badge
      WTF?

      Re: Serious question.

      1- satellites orbit in the same direction

      Where did this assumption come from?

      1. strum Silver badge

        Re: Serious question.

        >1- satellites orbit in the same direction

        Where did this assumption come from?

        Most satellites are launched, from near-equatorial launchpads, to use the rotation of the earth to give a little free boost to escape velocity. So, they tend to round thataway (unless they go polar or inclined).

  7. Dr. Ellen

    The experiment could be in space, and still not cause permanent debris. Simply have two satellites, aimed carefully at a convenient very-low-orbit crashpoint over the Pacific Spacecraft Graveyard. The immediate debris would make a lovely display, which could be examined for trajectory, brightness and spectrum. That'd give a rough idea of what came out of the crash, size and material and all. Of course there would be things that headed out - but it's an orbit. They'll be back, to very-low-orbit. The whole mess would decay rapidly into the atmosphere, and we'd know where to watch for it.

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