thanks for that answer, especially the explanation of how rad-hardening is usually done okay, swapping harddrives isn't a task. although it's quite a pita to copy the backup onto the drive (okay, it just takes some time, maybe somebody from mission control can do that via teamviewer or a similar system).but since SSDs are lighter, they might use them instead of regular hdds. bringing up another problem. the same situation that causes hot pixels on cameras (which can be erased from pictures quite easily) can also cause damages on the surface of flash-chips. and that can cause everything from slight pixel-errors in video files to severe malfunctions with the operating system.regarding your last paragraph: I guess that's quite a big problem, if the crew is approaching mars or some other planet/dwarf planet/asteroid, without much spare part supply. it's "easy" for ISS, just request a new device, delivered by the next soyuz, progress, htv, cygnus or dragon capsule. for example: on mars, supply is up to 2 years away, and depending on which approach is finally used, they might even consider not to send that spare part.
SSD/flash memory also has a limited life regardless of radiation. This is due to how they work; each block of memory can only be written to a few thousand times.
I was under the impression that all COTS hardware is almost certainly equipped with firmware modifications to keep fans running (no convective cooling) or in case of system without fans, small fans installed permanently.Also, I though the digital cameras had redundant firmware chips, so one could continue to use the camera even if the reprogrammable chip had fried because of radiation. I don't know if that applied to some previous camera models, though.
here's a quick source document I found on Texas Instruments Space Qualified components. Has a fairly good write-up. Check the beginning & end sectionshttp://www.ti.com/lit/sg/sgzt006d/sgzt006d.pdf
http://forum.nasaspaceflight.com/index.php?topic=36552.msg1315454#msg1315454in this thread, I asked about using standard electronics with a radiation shielding on satellites, and mentioned regular notebooks on the ISS. the discussion quickly started revolving around the notebooks, that they don't last long...so, I'm starting this thread here, because that discussion clearly doesn't belong into the other thread (spaceX entering the commercial satellite market) with a few questions:1. how long does consumer-electronic last? so far I saw some notebooks on ISS-videos and Nikon full frame cameras. or are those devices specially designed to work (or last longer) in space?2. what causes electronics to fail in space, whether directly exposed to space, like on satellites, on mars-rovers or perhaps on philae, or in a shielded environment like on the ISS?3. how about repairing those devices? especially on missions to other planets, a failing laptop can't be easily replaced, but they might have a few spare parts for those devices. is that more complicated in zero-g? (I'm thinking about small screws floating around).4. which parameters (radiation-shielding, temperature) are required to allow standard electronics to work for several years?
At what voltages and frequencies (or DC) is power supplied on ISS and other spacecraft these days? I seem to recall reading about some quite high frequencies (400 Hz?) being used and have wondered why (maybe less potential for arcing?).
Quote from: Proponent on 01/14/2015 08:56 amAt what voltages and frequencies (or DC) is power supplied on ISS and other spacecraft these days? I seem to recall reading about some quite high frequencies (400 Hz?) being used and have wondered why (maybe less potential for arcing?).The iron core in a transformer will saturate at a certain magnetic flux density. For 60 Hz (16.7 ms period) you need more iron than 400 Hz (2.5 ms period) to avoid that. When the core saturates it stops coupling flux from the primary winding to the secondary winding and then the primary winding just becomes a short. Think fire.
For further reading ex-NASA engineer extraordinaire John Muratore outlines the SpaceX approach to a non-radhardened solution. http://aviationweek.com/blog/dragons-radiation-tolerant-designhttp://en.wikipedia.org/wiki/Byzantine_fault_tolerance
If someone hasn't already noted this, for an interesting contrast, the Dragon cargo spacecraft uses a "radiation-tolerant" practice, rather than rad-hardening. In short: Add lots of voting computers.http://aviationweek.com/blog/dragons-radiation-tolerant-design
Quote from: MattMason on 01/16/2015 02:05 pmIf someone hasn't already noted this, for an interesting contrast, the Dragon cargo spacecraft uses a "radiation-tolerant" practice, rather than rad-hardening. In short: Add lots of voting computers.http://aviationweek.com/blog/dragons-radiation-tolerant-designYup, mentioned twice already on a one page (thus far) thread.
It may have been mentioned a couple of times, but I'll add here that the "fault-tolerant" design, at both the hardware-design and software-design level, will be the key critical piece of technology that will make the use of lower-cost (non-rad-hardened) electronics in space possible. And when solved, it also gets us flying electronics in space that are only a year or two-old, and thus flying electronic technology that is much closer to the state-of-the-art.
Quote from: AS-503 on 01/16/2015 05:13 pmQuote from: MattMason on 01/16/2015 02:05 pmIf someone hasn't already noted this, for an interesting contrast, the Dragon cargo spacecraft uses a "radiation-tolerant" practice, rather than rad-hardening. In short: Add lots of voting computers.http://aviationweek.com/blog/dragons-radiation-tolerant-designYup, mentioned twice already on a one page (thus far) thread. It may have been mentioned a couple of times, but I'll add here that the "fault-tolerant" design, at both the hardware-design and software-design level, will be the key critical piece of technology that will make the use of lower-cost (non-rad-hardened) electronics in space possible. So it is an important part of making standard-electronics work in space, and thus very relevant to this thread. And when solved, it also gets us flying electronics in space that are only a year or two-old, and thus flying electronic technology that is much closer to the state-of-the-art.
Quote from: Llian Rhydderch on 01/17/2015 03:36 pmQuote from: AS-503 on 01/16/2015 05:13 pmQuote from: MattMason on 01/16/2015 02:05 pmIf someone hasn't already noted this, for an interesting contrast, the Dragon cargo spacecraft uses a "radiation-tolerant" practice, rather than rad-hardening. In short: Add lots of voting computers.http://aviationweek.com/blog/dragons-radiation-tolerant-designYup, mentioned twice already on a one page (thus far) thread. It may have been mentioned a couple of times, but I'll add here that the "fault-tolerant" design, at both the hardware-design and software-design level, will be the key critical piece of technology that will make the use of lower-cost (non-rad-hardened) electronics in space possible. So it is an important part of making standard-electronics work in space, and thus very relevant to this thread. And when solved, it also gets us flying electronics in space that are only a year or two-old, and thus flying electronic technology that is much closer to the state-of-the-art.Have you stopped a bit to think about it? Who does the voting? How do they communicate their votes? How does the bonding, the layers and the doping react to radiation? How does it handle parasitic charges? They start from COTS, but at least industrial grade COTS parts. And that only works for LEO short duration.Are you aware that gamma rays and high energy protons can actually physically damage parts? How do you make sure you get the correct message from each IC? You need ECC in every single step, even in the cache lines. But that's not the worse part. What happens if you get an error in your voting logic? What happens if your voting IC gets damages because of a relativistic nucleus?
But that's not the worse part. What happens if you get an error in your voting logic? What happens if your voting IC gets damages because of a relativistic nucleus?
Den mussten wir dann in MacGyver-Manier mit LeatherMan-Tool, Sägeblatt und Rasierschaum reparieren. Der Rasierschaum hat verhindert, dass die Späne unkontrolliert wegflogen.
...dass nichtkritische Systeme der Raumstation am besten auf einem standardisierten Notebook laufen, weil man dann Ersatzteile hat. Das sind diese Lenovo Thinkpads, früher waren es die A31p, jetzt A61p.
Von denen haben wir sehr viele an Bord. Wenn die Weltraumstrahlung ein System zerschießt – und das passiert ab und zu mal, besonders an Tagen mit starker Aurora – nimmt man sich einfach ein neues, baut die Festplatte ein und es läuft innerhalb von 10 Minuten. Wenn die Festplatte zerschossen ist, nimmt man die heraus, die neue wird vom Boden aus mit den aktuellen Daten konfiguriert und das Ding funktioniert wieder.
Personal experience here with this too. They're not hard. Only thing I'll say is don't use SD cards, those things were by far the fastest element to fail in our experience. Something in them dies really quickly in radiation environments.
Quote from: mlindner on 01/19/2015 10:39 pmPersonal experience here with this too. They're not hard. Only thing I'll say is don't use SD cards, those things were by far the fastest element to fail in our experience. Something in them dies really quickly in radiation environments.SD cards need +12V to program/erase the "bits" inside them. Since most portable electronics don't have this voltage, there's usually a charge pump integrated onto the NAND flash chip that generates it. If that charge pump uses P/N junction diodes then I'd wager they're the failure point. Slam enough charged particles into the depletion region of a P/N junction and you will render the diode permanently open ("off") or permanently shorted ("on").
Curious if optical processors have been tried in space.If so, I wonder if they are more immune to radiation problems.
Quote from: watermod on 01/23/2015 12:53 amCurious if optical processors have been tried in space.If so, I wonder if they are more immune to radiation problems.Has anyone tried an optical processor yet? Anywhere?I thought they were still firmly vaporware. Interesting research, sure, but still quite a long way from practical applications.