back to article Japan to test self-destructing satellite to shrink space junk with string and an inanimate carbon blob

Japan’s space agency (JAXA) has announced plans to test a self-destructing satellite in the hope of commercialising the technology so the proliferating fleet of low-orbit kit doesn’t become junk. The tech involved was developed with Japanese sat-killer startup ALE Co. and sounds simple: satellites will be equipped with a …

  1. redpawn Silver badge

    What is the chance

    one of these sperm cells will fertilize the Earth?

    1. Spherical Cow Silver badge

      Re: What is the chance

      A million to one... uh-oh!

  2. Anonymous Coward
    Anonymous Coward

    Nice idea, hope it works.

    Lorentz forth -> Lorentz force. Unless these satellites have a speech impediment.

    1. redpawn Silver badge

      Re: Nice idea, hope it works.

      They are learning to program and it slows them down a bit, just enough to...

      1. Anonymous Custard Silver badge

        Re: Nice idea, hope it works.

        Either that or they're having flash-backs to Reagan and Star Wars?

        Or at least back to May 4th...

  3. cb7

    So if you reverse the polarity, you could speed up and hence raise the orbit of a satellite using electricity? Sounds cool.

    Obviously I've over simplified. You might have to modulate and pulsate at the right moments and have the tether face the other way to achieve the end goal, but it seems plausible to, in effect, use the earth's magnetic field for this "motor".

    1. Neil Barnes Silver badge

      Yes. There's a long and detailed Wikipedia article on the subject, which cleared up some confusion for me.

      It would be handy though if there were a way to get current from one end of the tether to the other without that return conductor being influenced by the magnetic field without having to rely on a plasma to transfer electrons... I wondered about a coaxial cable, in which the current might be induced in the outer but not the inner, but that's way outside my area of expertise.

      1. Spherical Cow Silver badge

        I thought the idea of a coaxial cable was to have zero net electromagnetic effect. The central core has its field centred at the centre (obviously) and because the outer sheath surrounds the centre the outer sheath also has its total field centred in exactly the same spot. So when one is positive and the other is negative the total is zero.

  4. This post has been deleted by its author

  5. Anonymous Coward
    Anonymous Coward

    Wouldn't it be better to at least try recover satellites first to be able to recycle the materials from it considering metal resources aren't infinite and that it isn't sensitive material/technology we're dealing with here?

    1. lglethal Silver badge

      You are aware that the recoverable resources from any satellite in low earth orbit would be massively dwarfed by the cost of sending up something to recapture them, right?

      Or where you thinking that the satellites should all be designed with heat shields (massive weight add on - upping the amount of fuel you need to get into orbit), so that they can deorbit on their own? Yes because the thought of a satellite (even a cubesat) undergoing an uncontrolled deorbit and making it back to the surface of the Earth at Mach 10+ is not a truly terrifying thought.

      1. Anonymous Coward
        Anonymous Coward

        I was thinking more of a way of recovering junk/defunct satellite parts and sending it back down in (very) large bulks rather than just mitigating further junk by obliterating it, but you are completely right, a major oversight on my part.

    2. Richard 12 Silver badge

      Start with the massive rocket

      The satellite itself contains hardly any material, compared to the dry mass of the rocket that put it there.

      Any capture-and-return would need to eat a lot of satellites to break even on the materials cost, even ignoring the monetary.

    3. Chris G Silver badge

      If you want to recycle old sat's, perhaps it would be better to use them in space.

      Launch a purpose built, AI equipped satellite that can scoop up old sat's and build itself into an autonomous space station with the parts.

      It would need an easy to remember name like......... Skynet?

      1. Anonymous Coward
        Anonymous Coward

        Broken Orbiter Reclamation Gizmo?

      2. JimboSmith Silver badge

        I hate to burst your bubble but there already are Skynet satellites...... and they predate anything James Cameron has done on the subject.

      3. Sean o' bhaile na gleann

        I sense an opportunity for Steptoe & Son in Space, here...

        1. Steve K Silver badge

          Salvage One

          Anyone remember the film "Salvage One"?

          1. Anonymous Coward
            Anonymous Coward

            Re: Salvage One

            Yep, it comes around like a stuck record every time there's a story about space junk.

    4. John Jennings Bronze badge

      err no

      A satellite is whizzing round at a considerable speed - its basically falling to earth all the time and missing, the energy (and thus fuel) required to perfectly synchronise a 'catcher' with a cubesat and return it would be massive.

      As to the elements being lost - 15000 tons of micrometeors strike the earth - every year. We are not going to run out of metal by sending a few KG into space. Given that each launch of each flight of microsattelite likely costs the guts of a ton in metal to send up (obviously not on reusable rockets) - then there is more sent up than is put in orbit. Reusable tech makes sense for the rockets themselves - not so much for the payloads.

    5. HildyJ Silver badge

      No good options

      Even if you get past the cost of sending a satellite capture device up and ignore the minimal recyclable value of cubesat components, we don't have a technology to capture satellites without the possibility of them breaking up into smaller pieces of space junk.

  6. ashdav

    Header picture

    Made me think of Dark Star.

    The original 1974 not the 2015 one.

    1. Ardly

      Re: Header picture

      Awesome film.

    2. oldfartuk

      Re: Header picture

      I first learned about Phenomenology from watching that movie.

  7. This post has been deleted by its author

  8. Anonymous Coward
    Anonymous Coward

    Stephen Gould Jumper book 4 EXO

    in this SciFi they had the tether made from braided metal wire hanging towards earth using the gravity gradient to pull the tether downwards

    1. Steve K Silver badge

      Re: Stephen Gould Jumper book 4 EXO


      That'll be the name for Elon Musk's next baby!

  9. Arachnoid

    Dak Star

    Bomb No 20 can you hear me?.........

  10. Chris Gray 1


    How long are those ElectroDynamic Tethers? Does the presence of those make it significantly *more* likely that collisions will occur?

  11. Mark 85 Silver badge

    Just a bit late maybe

    With all the ones being launched weekly by SpaceX, this seems be like closing the barn door after the horse got out.

    That aside, it's still a good idea to get stuff out of orbit and clean things up a bit.

    1. Spherical Cow Silver badge

      Re: Just a bit late maybe

      The SpaceX ones are low enough to deorbit in a few years just from atmospheric drag. In fact we have no way to _stop_ them from deorbiting.

  12. Aussie Doc Bronze badge

    Yeah, sure.

    And there was me thinking we were going to get frickin' lasers.

    Disappointed now.

    1. oldfartuk

      Re: Yeah, sure.

      If I were creating the world I wouldn't mess about with butterflies and daffodils. I would have started with lasers, eight o'clock, Day One.

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