High-Temp Electronics For Venus Exploration, recent advances |
High-Temp Electronics For Venus Exploration, recent advances |
Mar 13 2013, 03:36 PM
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Member Group: Members Posts: 127 Joined: 20-April 05 Member No.: 291 |
(MOD NOTE: Started a new topic for this discussion to continue. Please remember the 'no sci-fi engineering' provision of rule 1.9. Have fun!)
Also, since I'm thinking about surface operations on Venus, the state-of-the-art in high temperature electronics has advanced quite far in the past decade. Its now possible to buy off the shelf chips from vendors designed to operate at the 250-300 C range. Meanwhile basic functionality has been tested at and beyond the temperatures needed for long-term surface operations on Venus: http://www.grc.nasa.gov/WWW/SiC/ http://www.gizmag.com/extreme-silicon-carb...ctronics/16410/ http://www.grc.nasa.gov/WWW/SiC/publicatio...Contact2010.pdf Another decade or so and a long-term Venus lander could be possible with (practically) off the shelf electronics! |
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Jun 11 2013, 12:51 PM
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Junior Member Group: Members Posts: 20 Joined: 19-March 13 Member No.: 6897 |
The big problem, I am told, is memory. We can probably make devices with hundreds or perhaps a couple thousand transistors (enough for a microcontroller, the Intel 4004 had 2300 transistors), but we pretty much can only do SRAM right now, which limits us to maybe 100-200 bits (not even bytes) in the near term (next few years). And even that is difficult. I don't get the idea that it's just a few steps to a big VLSI.
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Jun 13 2013, 05:37 AM
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#3
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Senior Member Group: Members Posts: 1591 Joined: 14-October 05 From: Vermont Member No.: 530 |
I don't get the idea that it's just a few steps to a big VLSI. As an example, I don't necessarily think that once a technology is reliable, there's any hurdle between 4004 and 8085 these days. Took them 5 years in the 70s, but the lithography was all new. Today, there's no point in technology development where anyone would cut and run with a 4004 thinking they next step to the 8085 wouldn't be quickly surmountable. Sure, a Pentium (22 years) might be a leap. I don't think it serves much purpose to imagine it will take as many years to move up the Moore's law curve as it did in the 70s, when microns were considered really small geometries. There's not going to be a long period comparable to the 70s when we could make microcontrollers, but only laughably piddling ones. Plus, the thing is that even if it did take the whole 5 years it did in the 70s, that doesn't seem that long when you're talking about unmannedspaceflight! I think it's conceivable they could solve board reliability and instrument reliability before they solve IC reliability, and someone will send a system with discrete components. I just don't think it's that plausible we'll send one with a 4004-level IC when the wait for 8085 or 8086 will not be long at all. |
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Jun 13 2013, 12:56 PM
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#4
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Junior Member Group: Members Posts: 20 Joined: 19-March 13 Member No.: 6897 |
As an example, I don't necessarily think that once a technology is reliable, there's any hurdle between 4004 and 8085 these days. Took them 5 years in the 70s, but the lithography was all new. Today, there's no point in technology development where anyone would cut and run with a 4004 thinking they next step to the 8085 wouldn't be quickly surmountable. Sure, a Pentium (22 years) might be a leap. I don't think it serves much purpose to imagine it will take as many years to move up the Moore's law curve as it did in the 70s, when microns were considered really small geometries. There's not going to be a long period comparable to the 70s when we could make microcontrollers, but only laughably piddling ones. Plus, the thing is that even if it did take the whole 5 years it did in the 70s, that doesn't seem that long when you're talking about unmannedspaceflight! I think it's conceivable they could solve board reliability and instrument reliability before they solve IC reliability, and someone will send a system with discrete components. I just don't think it's that plausible we'll send one with a 4004-level IC when the wait for 8085 or 8086 will not be long at all. I think you're missing something, here... With high-temp electronics, we don't have access to Moore's Law. There are just one or maybe two places that really are even trying to do complex integrated circuits. There's very, very little financial incentive for improvement, it's essentially ALL gov't funded. The state of the art can improve, but it is a direct function of money spent, not purely time. This is markedly different from the situation with the early IC CPUs like the 4004, where you have a huge market for improvements. Nowadays, tens of billions of dollars are spent on fabs and improving the technology for making conventional integrated circuits. Definitely not the case for silicon-carbide circuits, nor is it likely to ever be so. The market is tiny, you can't simply wait for it! That said, an 8-bit architecture may make more sense than a 4-bit even at the extreme limit of minimal transistor count. |
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