"Popovkin said that some microchips used on the craft were imported and possibly of inadequate quality to resist radiation. He did not specify where the chips were manufactured.
"Yuri Koptev, a former space agency head who led the Phobos-Ground investigation, said 62 percent of the microchips used in the probe were "industrial" class, a less-sophisticated level than should be used in space flight."
How long has Russia been using I class chips, rather than S class chips, in its spacecraft, and do they use only S chips in manned craft?
Or did somebody just get a coordinate transform wrong? The images at
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suggest that the vehicle ended up in a stable configuration but with the wrong end pointing towards the Sun. Be really embarrassing if this was just a case of a dropped minus sign...
I worked at a semi where we transformed some standard products into class S. All we did is put them on epi, which wasn't common at the time, with a few tweaks to the process. Or that is all they told me. ;-)
It may be that COTS chips on epi work fine in space, and epi is very common today. SOI also improves rad hardness.
I tried to find stats on percentage of bulk CMOS, but nothing found. I suspect that is the kind of information you need to buy.
Of course, where would you find enough engineers capable of doing decent latch-up resistant designs on bulk these days?
One of the sleazier semis I worked at would do the initial run in both bulk and epi. If there was a latch up issue in bulk but the epi worked, you sold the epi product until pricing demands made a redesign on bulk profitable.
As I always state, if the parameter is not on the data sheet with tested limits, it doesn't exist. Don't blame the manufacturer if your sub sinks or satellite falls to earth because some spec you needed was only listed as typical. There are custom flows just for such situations.
The page says that Phobos Grunt is aerodynamically stabilized with the heavy tanks forward and the sun cell panels as brakes behind.
So the panels should be illuminated one half orbit.
Of course that could be wrong, but the sun sensors should be able to discover that the Sun isnt shining on them and start searching for it, shouldnt they ?
How long could the probe work with recharge half the time ?
Often the cooling ribs are under the solar panels for best shade. Have they overheated due to be illuminated, so the electronics are cooked ?
...These "sleazy semis" were far more the norm than the exception, especially about 17 years ago when I was helping design the SummaJet for SummaGraphics. This one particular common IC - and for the hate of me I can't recall what sort of amp chip it was - when bought in bulk, over 80% of the chips would lock up within 96 hours of continuous operation. And by "continuous operation", this meant either continuous torture-test printing - a real "Romulan Engineering" test that one - or just sitting there waiting for a print job. There were a dozen manufacturers we went through, and every single bulk batch we got had either the same lockup rates, or exceeded those rates by as much as
15% even though they'd run a few days longer before locking up.
...But that wasn't the punch line. Not only could we not determine just *what* was triggering the lockups - it wasn't any errant signals and/or voltage issues coming down the line from the main proc on the processor/RAM board that was the plotter's brains - but if you let the plotter sit there locked up for more than 48 hours, it was pretty much guaranteed that within the next 24 the IC in question would actually
*catch fire*, spewing flame out like a gas jet when it first ignited. I actually witnessed this on four separate occasions, and we actually caught it not only on videotape with a camera about a foot from the IC, but on the lab's security cameras just before one set the whole proc board alight and triggered the fire alarms. Luckily the sprinkler systems didn't go off, because about 300 rolls of various plotter paper and 25 years worth of stored yet-to-be-digitized blueprints would have been ruined. And trust me, nothing stinks worse in a print environment than mildewed vellum :O
...However, when we got samples that had been run through extended pretest by the manufacturers instead of just the bulk testing, the lockup rates dropped to less than 5% of the samples supplied, and where a chip that locked up once was pretty much guaranteed to lock up again and again and again without un-fail, those that did experience a lockup usually did not experience a lockup again. And out of all the samples received from the various chip houses, not one single IC ever caught fire. We still stuck a heat sink on it just to play safe when we shipped the final product - especially the custom jobs we did for Mutoh - and AFAIK not a single SummaJet ever caught fire in the field even after CalComp bought the place out and finished up the sales contracts.
...And alas, we never *did* find out just what in the bulk test process was causing those chips to become so damaged that they would immolate. The only in-depth testing we had time to do other than to verify that the signal and voltage issues were either not there and/or not our fault was to strip back the outer housing and take a look at the inner circuit before and after lockup - and in one case, after immolation had started but was suffocated before too much damage was done - and see if anything was out of the norm. The only damage we saw before IC install was the "arclight" or "craters of the Moon" effect that occurs when too much static discharge has been passed through an IC through improper handling - read: touching the pins with bare fingers, no grounding strap at the very least, etc - and the ICs that had this microdamage were also ones prone to lockup. Subsequent analysis showed no additional evidence of "arclighting", which ruled out damage caused by our assembly team during installation and soldering, and the one that briefly caught fire also showed no additional "arclighting" - at least when we compared the unimmolated areas to photos of the pre-installed IC.
...So, to Bottom Line it all, it was something in the bulk test process that was damaging the ICs that wasn't duplicated in the samples sent to us that were extensively tested at the foundries. What that was, however, was never determined, and due to time constraints and shipping schedules, it was determined that we'd pay the chip houses extra to ship us the e-test samples as if they were the requested bulk shipments, stretch out our delivery dates a bit, and pass the cost per chip on to the consumer, which only added about $20.00 USD per unit. We were later able to offset that by about $5.00 USD by switching to a different resin for the inkjet cartridge holder wedges - that's a clusterfrack that deserves a whole book chapter to fully describe the history of - and trimmed another $5 to $7.00 USD per unit for those who bought a SummaJet with the full 32MB of RAM installed, as we got a price break from a RAM supplier. That left ~ $4.00 USD to pass on to Joe Customer, but for an inkjet that performed
95% identical to an HP job, using the same carts, operating at the same speed, and all for about 30% less cost, that four bucks was just a drop in the bucket compared to the sales tax on such an item.
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