Short circuit on ISS

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An electrical failure on ISS has deprived ISS of one of its main circuits.

They have alternative wiring and are using that, so that all equipment is presently functioning. However, a similar failure in 2014 required a spacewalk to fix. Moreover, they don’t have the necessary spare parts on board to fix the problem. They will have to be shipped up, and it is too late to put them on the Cygnus freighter now packed and ready for launch on December 3.



  • Gealon

    I don’t want to come off sounding Too sarcastic, but some prototype interplanetary vehicle this is.

    “No good spare parts for the job are on board.”

    Does that mean they went into the box of fuses and only found blown ones? Who does that? If this has happened before, why isn’t there a spare onboard, ready to be swapped out at any time? I can’t imagine it’s a scheduling issue, just bump someone’s science project and fly the thing. Astronaut safety should be of primary concern and a replacement for everything small enough to fit though the airlock should be up there. Granted it’s good that they have redundancy built into the system, but from that I’m reading that redundancy is still channeling power through the same component. What happens if it fails completely?

    I’m expecting too much though. The station isn’t being used for useful science, it’s political tool and as such properly maintaining it isn’t a priority. Heck, they’ve already put a deadline on it for decommissioning. I know this post is sort of turning into a rant but I watched them build this thing year upon year with wonder. However when it was finally completed after ten years of construction there was immediately talk about dumping it and when that would happen. It was then I realized what NASA really is and it’s sad. The faster we can take space private the better because only in the insane logic of bureaucracy can you justify spending billions over more then a decade to build something only to plan to ditch it once it’s finished and then spend billions more over TWO decades to build something that will never fly.

    Sorry Rob about getting emotional but the article just made me mad and highlights everything that’s wrong with big space. They waste our money on building this huge machine that could do great things, and then don’t even keep it properly stocked.

  • If you read my book Leaving Earth you would read me ranting in much the same way as you do here.

    The reasons the parts are not on board ISS however is not entirely NASA’s fault. The launch failures of both Cygnus and Dragon has limited cargo runs to the station. NASA had done the right thing having these two new private cargo companies, but unfortunately both had a launch failure.

  • Edward

    Gealon wrote: … a lot.

    1) The reason that they don’t just bump a science experiment is that the problem is not urgent. Doing science is urgent, because that is what this very expensive laboratory is for, and the previous three lost payloads over the course of the past 13 months (Robert didn’t mention that the Russians also had a launch failure of a cargo run) have reduced the amount of experiments available to the astronauts/cosmonauts.

    2) It is not a fuse, it is a circuit breaker, which just needs to be flipped once the short circuit is fixed. It is the equipment, not a fuse, that is shorted that needs replacement. There are still seven other redundant routs for the power, so there is no urgency (see item 1).

    3) packing a spacecraft is not like throwing stuff into your trunk. Weight, center of gravity, and mass moment of inertia have to be accounted for, otherwise you will have surprises while guiding your spacecraft to its destination (next time you watch “Apollo 13” notice that they move a couple hundred pounds of unneeded equipment in order to make up for the lack of moon rock mass during the reentry phase of the mission).

    4) Opening and repacking the spacecraft takes time, and this is late in the schedule. A replacement part has to be obtained, and tested. Making sure it works before launch is a good idea, because everyone would likely complain if it were hastily packaged and flown but then did not work. A certain amount of time is needed to put the spacecraft onto the rocket, and repacking the spacecraft could delay this operation. Since this is not an urgent problem, it is not worth the extra trouble, cost, delays, and likely error(s).

    5) Things done in a rush often get fouled up. Since this is not urgent, it is best to plan it all very carefully and make sure that things do not go wrong. It isn’t as though we accidentally left an astronaut behind and have to rescue him before he dies.

    6) The ISS is not a dry run for a Mars mission, but is a proving ground for equipment, processes, procedures, and human requirements for such a mission. This is where we find out what is needed, what breaks down and how often, and how compatible various people are with each other during long durations of small crews.

  • mkent

    To add to what Edward wrote, the last word I saw is that a replacement part will be flown on the cargo run after next, currently scheduled to be Dragon’s SpX-8 run on 03 Jan 2016. As the shorted equipment will have to be replaced on EVA, and those things take time to plan and train for, there is time to wait for the January flight.

    I think from a big picture standpoint, the bigger lesson to learn is that having regular cargo runs to the ISS is a good thing. Since CRS-2 is taking over for ATV and possibly HTV, I would like to have seen NASA go with six cargo runs a year from three providers (3 SpaceX, 2 Orbital, 1 Boeing) on a regular every-other-month schedule. It would benefit not only maintenance issues but also commercial experimenters who, more than anything, value schedule reliability and repeatability.

    Alas, NASA wants only four, or at most five, cargo flights a year.

  • Gealon

    I am actually aware of a lot of what was said and would like to apologize again, it was a rant but I knew I was ranting so I kept it civil. My fuse comment was actually more to illustrate the absurdity of the words I read in the article, “No GOOD part.” was said to be in board, suggesting that they do have a replacement and that it is also defective, which is the equivalent of going into the box of spare fuses and only finding blown ones. My point was, why has the defective part been kept up there and no replacement flown yet.

    I also understand the complexities of packing, stacking and flying a rocket, and again, my comments were not as detailed as I would have liked and somewhat more emotionally charged then would normally be the case. Yes, they have 7 other busses to rout power through and yes there have been a string of launch failures, but it still does surprise me that a replacement wasn’t on hand. That coupled with the “No good” qualifier and my general frustration with the program just boiled over.

    Thanks to all three of you for understanding and your constructive comments.

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