Timeline for answer to How can I keep the computers on my spaceship from temperature related death after a hull breach? by user64742
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| Dec 23, 2016 at 2:45 | comment | added | user64742 | @BenVoigt the crew needs to be protected from the radiation. One would assume that the hull is the protecting the crew through some kind of lining. If that is breached, then neither the crew not the computer is protected. Seems logical to me? If we're sectioning off the computer than why not just get rid off the air in that region as well? The ship would be lighter. | |
| Dec 23, 2016 at 2:01 | comment | added | Ben Voigt | Unless you are postulating some sort of magnetic bottle (and if you are, then getting it reactivated to protect the crew is a priority, with protection of the computer systems as a happy side effect), cost savings ("cutting corners") is exactly why radiation shielding would be limited to only the crew compartment. The server room would have no radiation shield to be breached. A sufficient amount of lead simply requires far too much mass. There simply is no relationship between pressure hull and radiation shield. | |
| Dec 23, 2016 at 1:52 | comment | added | user64742 | @BenVoigt also, not all systems are designed perfectly. People cut corners. Things end up shoddy. Mistakes happen. Considering that radiation might be an issue is important to consider in an incident like this. The last thing anyone should ever do is assume a vector for failure should be ignored because chances are.... that will be the place that fails. I do not assume the radiation containment has failed. I assume the computer has no shielding. The ship itself is the shield. I assume that whoever designed the ship assumed the hull would never be breached. Hence why overheating is an issue. | |
| Dec 23, 2016 at 1:50 | comment | added | user64742 | @BenVoigt im just posting an answer saying the op might have this to consider in planning their scene. They seem to want to justify a computer system breaking down due to a hull breach and radiation could effect the systems prevent the computer from combusting. At some point in the chain, theres going to be a system that can be damaged. An asteroid hit the side of the ship. I'd imagine that nobody prepped for such a disaster; hence the need to find a gameplan to stop critical failure. I assume this is a scenario where the characters need to think on the fly and not a planned for event. | |
| Dec 22, 2016 at 23:05 | comment | added | Ben Voigt | The "less-critical" systems will already be designed for operation in radiated environments, just with a lower level of redundancy (perhaps you have just two copies, and when they disagree, you re-run the entire computation which after all is non-critical -- at the same time the critical systems might have 9-way redundancy, three copies each of three different designs, to minimize the chance that the manufacturer dutifully made multiple identical copies of a design flaw). Remember you can have an awful lot of extra silicon for the mass of lead-lining a computer case. | |
| Dec 22, 2016 at 23:04 | comment | added | Ben Voigt | I see in your comments on other answers, you consider the problem to be the loss of integrity of shielding, thus increased radiation. But the fact is, it's much cheaper (in the metrics that matter, mass and volume) to make computers work in space via redundancy and radiation-hardening (larger transistor geometry) than shielding. The only reason the hypothetical spacecraft has any shielding at all is for the benefit of the crew. | |
| Dec 22, 2016 at 22:59 | comment | added | user64742 | @BenVoigt fair enough, but by the same reasoning the computer shouldn't fail from heat as I can just wrap everything in coolant. It's still worth mentioning to keep in mind. There might be less-critical systems using microprocessors like for scientific databases used as reference material. :) | |
| Dec 22, 2016 at 22:52 | comment | added | Ben Voigt | You can make very complicated computers with 70nm production process. You'll need an order of magnitude more silicon than the same computer power using 14nm, but the mass/power/volume increase is not so great as to make it prohibitive. Alternatively, you can use an in-between amount of silicon, and put redundant copies of the 14nm circuitry and use majority-vote and other error-correction techniques (the voting logic had better be the large geometry, but it's a very small fraction of the total). | |
| Dec 22, 2016 at 22:48 | comment | added | user64742 | @BenVoigt how is that at all relevant? An advanced spaceship needs a more complicated computer than that. | |
| Dec 22, 2016 at 19:55 | comment | added | Ben Voigt | It's all about the size of individual transistors. For the geometries used in new consumer processors, like 14nm, individual high energy particles will cause a substantial jump in the voltage where they hit, changing the result. Older larger geometries have more capacitance on the gate of each MOSFET, making them considerable more tolerant of radiation, so they tend to still be used for computers intended for space (as well as near X-ray machines, etc). Making transistors larger works for logic circuits and memories alike. | |
| Dec 22, 2016 at 2:19 | history | answered | user64742 | CC BY-SA 3.0 |