back to article Satellite cannon starts shooting Doves, this time under control

The nano-sat launcher aboard the International Space Station has stopped malfunctioning and started spitting its payload into space as intended. The NanoRacks deployment was due last year, but was interrupted when it started launching its 6kg Planet Labs Doves satellites without instructions. The fault was traced to over- …

  1. Crazy Operations Guy

    What is their life-span?

    I've been looking into putting a couple of amateur satellites up in orbit and I was wondering what kind of life one of these things has. Depending on actual cost and life span, you could probably build a pretty robust AmSat mesh and just send a couple up every so often to replace the dead ones.

    And if not for AmSat, I'd like to see someone create a network of satellite for the free exchange of data without government interference (Radio Free Space, so to speak)

    1. Anonymous Coward
      Anonymous Coward

      Re: What is their life-span?

      Interesting idea, but costs must be met first. To avoid government involvement, a new source of funding is required. Maybe crowdfunding? Like, "Everybody please contribute ten shekels to the 'SkyTubes' project."

      Happily there now exist alternate, non-govt. "Go to space" outfits that may be approached.

      I'm thinking this thing is actually doable! Will it fill a need tho? Hmmm...

      1. deive

        Re: What is their life-span?

        People are doing these things! is interesting although I would prefer something a little less "curated". Good times.

  2. gerdesj Silver badge

    Over tightened screws?

    Over tightened screws in a satellite seems a bit naff. Last year I found the bolts on my car's front wheels were not torqued properly (or at all) after an MoT and a replace of tyres. I nearly reached for a lawyer instead of a wrench, when I eventually traced the knocking noise on deceleration. Thankfully wifey's car didn't end up on its nose first or worse.

    How the hell can something as basic as torque be screwed up on something so expensive and destined to be rather remote?

    1. Flocke Kroes Silver badge

      Re: Over tightened screws?

      Real quotes from PHBs: "I know how to tighten screw", "Using the torque screwdriver makes me look incompetent" and "Look! I got it to hold together using only two screws!".

      1. Anonymous Coward
        Anonymous Coward

        Re: Over tightened screws?

        So they really "put the screws" to this thing, and that drove it into auto-fire mode? Somehow I'm not surprised.

    2. Mark 85 Silver badge

      Re: Over tightened screws?

      How the hell can something as basic as torque be screwed up on something so expensive and destined to be rather remote?

      Easy-peasy... someone let Murphy into the building. Or maybe he was already there and they just woke him up.

    3. cray74

      Re: Over tightened screws?

      "How the hell can something as basic as torque be screwed up on something so expensive and destined to be rather remote?"

      It happens all the time in the aerospace industry. The mis-torqued situations I've seen seem to go like this:

      1) A new aerospace gizmo is designed. The engineer(s) behind the relevant drawing carefully, painstakingly address common issues for the fastener: material compatibility with the socket, galling, finishes (dry film lubes or wet installs - careful of off-gassing), fastener type/size/specification, and so on. However, no one bothers specifying torque because they don't think it's necessary for all those finely-trained, extensively-experienced guys on the factory floor (or haven't personally experienced a torque problem, or expect Manufacturing to step in and write give decent input on the assembly procedure).

      2) Some years later, enough of the gizmos have been in service that lack of torque control is causing problems. The drawing is updated, assembly procedure is expanded, and more paperwork is added so the tech doing the bolt-torqueing is now required to write down the torque applied to each of the 37 bolts he's responsible for. Torque problems vanish, customer signs off on the changes, everyone goes out for a beer.

      3) Torque problems resume a year later, mostly occurring in older gizmos but also in some coming out of the factory. Drawings and instructions are verified as being correct; paperwork shows the techs are doing the correct job (or at least filling out the paperwork with the correct numbers); attempts by engineering to interrogate the responsible tech properly (empty room, one chair, bare bulb swinging overhead, etc) are blocked by union representatives, so engineers must content themselves with shop floor chats where the tech swears they're following the orders the engineers wrote.

      3a) Finally, an intern assigned to sift gizmo data realizes that all the gizmos having trouble have either undergone recent maintenance in which 37 critical fasteners are removed and replaced, or they failed testing in the factory and had to be repaired, which also entails all 37 fasteners removed during the repair process.

      3b) A quick check of the depot maintenance process shows that the maintenance instructions do mention torque wrenches, but a site visit reveals the customer's techs prefer their own socket wrenches and were using the printed maintenance instructions to prop up a wobbly table. Meanwhile, the factory's own repair procedure was never updated to reference torque for the fasteners when the drawings and assembly procedure were fixed a year ago. The repair instructions are updated, the customer signs off on the changes, and everybody goes out for a beer.

      4) 6 months later torque problems resume, this time caught on the factory floor. It turns out the fastener vendor changed the passivation process on the stainless fasteners to something more eco-friendly after being threatened with plant closure by the local regulatory body. The vendor's hasty study and certificates of conformance claim the fasteners perform just like the last ones, so Procurement didn't notify Engineering of the change. However, now the torque characteristics are different despite the vendor's claim. A review board is held, drawings updated, instructions (all of them) updated, a representative visits the customer at their maintenance depot, and all will work well for at least the next 3 years.

      Of course, if you're only building a single gizmo and installing it on a space station where maintenance is infrequent and difficult, then that learning curve is not possible.

      1. Trigonoceps occipitalis

        Re: Over tightened screws?

        In the early days of military mechanization the Driver/Mechaninc had a list of checks to perform before first use every day. Among "oil level", "water level" etc. was "check tightness of cylinder head bolts". This was easily accomplished with a spanner and applying a quarter turn on each bolt. Result: many head bolts shearing.

        Of course the PHB was always helpful. During an inspection the inspecting officer asked a driver/mechanic "Is it pinking?"

        On receiving the reply "No."

        PHB says "Well, get it pinking right away!"

        Hands up those who think Scott Adams makes it all up.

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