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Unmanned Spaceflight.com _ Venus _ High-Temp Electronics For Venus Exploration

Posted by: dtolman Mar 13 2013, 03:36 PM

(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-carbide-electronics/16410/
http://www.grc.nasa.gov/WWW/SiC/publications/EDLOhmicContact2010.pdf

Another decade or so and a long-term Venus lander could be possible with (practically) off the shelf electronics!

Posted by: tasp Mar 13 2013, 05:50 PM

Having electronics operate at a higher temperature works 2 ways to make for a longer operating time on the surface.

Firstly, it takes longer to heat them up more, and also, the rate of heat flow into the probe decreases as the temperature difference between inside and outside decreases.

Additionally, having a wider temperature operating range might allow the use of different/better phase change heat absorbents.

We could be seeing quite a jump in operating time that's possible.

Posted by: Robotbeat Mar 25 2013, 04:30 PM

Of course, if you can operate at 500C, you don't need to have phase/change...

Resistors, Capacitors, inductors, all those sorts of things can work at 500C, though not the usual components. A resistor is fundamentally a simple device, as are capacitors and inductors... They can technically be constructed entirely with just some conductor and some insulator material.

Now that we have silicon carbide ICs of tens of gates operating at 500C, lots of stuff is possible. A turing-complete computer (provided you have some sort of memory, could be coil or capacitor based) can be made with just a couple hundred gates, though you have to be satisfied with very low performance (maybe just a 4-bit or 8-bit computer, but it's Turing Complete so can simulate higher). Whether it's worth it...

Posted by: hendric Mar 25 2013, 05:02 PM

QUOTE (Robotbeat @ Mar 25 2013, 10:30 AM) *
Now that we have silicon carbide ICs of tens of gates operating at 500C, lots of stuff is possible.


http://spectrum.ieee.org/semiconductors/devices/silicon-carbide-logic-circuits-work-at-blistering-temperatures

has some interesting details. Problem now isn't the semiconductor per se, but everything around it such as interconnect between the transistors (metal layers) and packaging etc.

Posted by: stevesliva Mar 25 2013, 06:51 PM

In addition to high-temp industrial applications, I wonder whether technologies like this could eventually avoid the need for ridiculous active cooling of server farms. I think the ideal would be servers that reliably operate around 100C, so that you could simply cogenerate (if that is the right term) by circulating water and creating steam. Right now 40C is the typical limit.

Posted by: nprev Mar 26 2013, 12:24 AM

Silly question: How are they doing surface-mount boards? My first guess is silver solder, which is what is used on aircraft engine thermocouples, but curious to see if a better technology has arisen.

Posted by: siravan Mar 27 2013, 12:14 AM

I wonder about sources of power. Is there any high temperature solar panel? Also, there is not much light on the venus surface. I remember Venera description of "same as noon in a winter day in Moscow", which is probably not a whole lot. RTG is worse. To generate any electricity using a thermocouple, one needs a temperature gradient, which would be extremely hard to maintain on venus.

Posted by: ElkGroveDan Mar 27 2013, 12:19 AM

QUOTE (nprev @ Mar 25 2013, 04:24 PM) *
Silly question: How are they doing surface-mount boards?


Tungsten solder, Nick. I have a patent pending.

Posted by: nprev Mar 27 2013, 03:24 AM

I'm officially your distant relative now, Dan, and I got a few bills... tongue.gif

Seriously, this is not a trivial problem. A Venus lander of any sort either requires a VERY well-controlled temperature environment for its electronics (which IIRC was the Venera strategy) or not only electronic components that can survive extreme temp swings during the cruise phase but also the same for all required electrical connections.

The latter are obviously quite vulnerable to materiel expansion/contraction cycles, which ultimately loosen connections over time and introduce either spurious or high-resistance interface points which can do all sorts of nasty things to signal flow. (For example, MIL-STD-1553 data buses really don't like impedance changes; tends to turn perfectly good data words into gibberish.)

How I see this playing out is a loosening of environmental control constraints over time for the silicon itself but capability bounded by a hard constraint on connection methods unless suitable (and workable, as Dan pointed out) connection/wiring alloys of some sort can be developed that are extraordinarily resistant to thermal cycling. That's a rather daunting challenge in metallurgy.


Posted by: mcaplinger Mar 27 2013, 03:39 AM

QUOTE (nprev @ Mar 26 2013, 08:24 PM) *
The latter are obviously quite vulnerable to materiel expansion/contraction cycles...

The cruise environment is fairly benign and once you get to Venus it's just hot all the time, there isn't a lot of diurnal variation. Exactly what the interconnect is made of is another question. That said, the SiC components are at a very early level of development so I'd say we are quite a ways away from having real and capable systems that would work at Venus ambient conditions.

RTG-powered refrigeration systems are feasible:
http://web.archive.org/web/20010106124800/http://www.msss.com/venus/vgnp/vgnp.txt.html

but for the foreseeable future I think short-lived landers are all we are likely to see, unfortunately.

Posted by: Explorer1 Mar 27 2013, 03:44 AM

If one is willing to constrain the landing site by altitude the engineering challenge can probably be lessened as well. Maxwell Montes is almost 100 C cooler that the mean; any lander would last a bit longer there and at the other high points.

Posted by: ElkGroveDan Mar 27 2013, 01:24 PM

QUOTE (nprev @ Mar 26 2013, 07:24 PM) *
Seriously, this is not a trivial problem. A Venus lander of any sort either requires a VERY well-controlled temperature environment for its electronics (which IIRC was the Venera strategy) or not only electronic components that can survive extreme temp swings during the cruise phase but also the same for all required electrical connections.

It's a real problem but I'm confident that existent materials technology can solve it -- especially the problem of conductive connections. I would imagine a mechanically secure solution such as clamping or spiral threading which is secondarily secured by a high temperature polymer. (If I were building it in my garage I'd be using RTV silicon or two part-epoxy which are reliable to 600F. I'm sure the JPL toolbox has even better stuff in it).

The electronic components are another story but frankly I'm pretty certain there are already temperature rated ICs and such in use in military and industrial applications which offer a starting point for this kind of high-temperature electronic circuit design -- probably servos, relays and optical applications as well.

Posted by: mcaplinger Mar 27 2013, 02:41 PM

QUOTE (ElkGroveDan @ Mar 27 2013, 06:24 AM) *
(If I were building it in my garage I'd be using RTV silicon or two part-epoxy which are reliable to 600F.... frankly I'm pretty certain there are already temperature rated ICs and such in use in military and industrial applications which offer a starting point for this kind of high-temperature electronic circuit design...

Venus ambient is around 450C or almost 900F. There are no ICs I'm aware of that get anywhere close. Most mil-spec parts go to 150C or maybe 200C in a few cases (junction temps, not ambient.)

Posted by: siravan Mar 27 2013, 03:15 PM

One small thing in favor of high temperature electronics for Venus is that, while very high, the temperature is relatively stable. You don't need components that works at both 20 C and 450 C. They only need to work at 450+/-50 C, which is probably somewhat easier task. The lander can have a separate set of electronics for the cruise and native high temperature ones after landing.

Posted by: mcaplinger Mar 27 2013, 04:20 PM

QUOTE (siravan @ Mar 27 2013, 08:15 AM) *
You don't need components that works at both 20 C and 450 C.

That would enormously simplify testing, though.

For our Venus proposals we spent a fair amount of time worrying about how we could even simulate the environment in any practical way. How do you put a scope probe on something that has to be at 450C to work?

Posted by: siravan Mar 27 2013, 05:16 PM

Agree. I didn't think of it from this aspect. But in the end of day, you cannot rely solely on testing at 20. You need to test in a similar environment as Venus. Also, what about the atmosphere? I guess CO2 at 90 bars and 450 C is rather corrosive.

Posted by: Robotbeat Apr 5 2013, 05:56 PM

I've found a microcontroller that's supposed to work at 250C:
http://www.ic72.com/pdf_file/i/141332.pdf
Doesn't look to be widely available, but it's still the very best I've found for a microcontroller (it's hard to even find transistors in this range...).
http://www.ims.fraunhofer.de/news/detailansicht/article/high-temperature-electronic.html

That's getting close. Some people think the highest altitude parts of Venus are around 350-380C (100 degrees cooler than the average surface). This would allow long-duration stays in the lower parts of Venus's atmosphere (tethered balloon?) or perhaps make simple cooling techniques feasible (high-temperature solar panels hooked directly up to Peltier cooling devices... though the long and hot night would be a problem...).

Which reminds me, are there any electronics that could /survive/ at 400C, even if they can't operate at that temperature? The instruments could be operated only during the daylight when there is power to run the cooling equipment. Of course, operation by an RTG (even a small one) would be preferable, but that increases the minimum cost significantly. Which reminds me, are there any betavoltaic devices (far cheaper, less restriction on usage I think) which can operate at 400C? Too bad they only output on the order of 1E-6 Watts. We need at least one Watt before we can talk about cooling electronics (more like tens of watts, for a very small device).

What is the insolation (Watts per meter squared, not just direct but also diffuse) at noon on the surface of Venus?

Posted by: stone Apr 8 2013, 06:34 AM

All the ideas are very strange, but NASA Glenn Research Center is already working on it.

http://www.lpi.usra.edu/meetings/ipm2012/pdf/1133.pdf
Development of a High Temperature Venus Seismometer and Extreme Environment Testing Chamber

A lander mission without camera is not a mission.
One point is: Is it possible to have a CCD or MOSFET camera at 4500-500C?



Posted by: djellison Apr 8 2013, 01:32 PM

QUOTE (stone @ Apr 7 2013, 11:34 PM) *
A lander mission without camera is not a mission.


Yes it is. Not all spacecraft can, should or must carry cameras. Would it be nice to take a more modern imaging suite to the surface of Venus? Obviously.

There is still huge quantities of science to be done without one, however.

Posted by: dtolman Apr 8 2013, 03:00 PM

The Solder question is very interesting. Looking into the state of the art for down-hole operations, it seems the solders used are at the very edge of being useful in their current applications (150-200 C) - for COTS it seems the mix of 5% tin, 93.5% lead, and 1.5% silver is useful up to ~250 C.

Beyond that point it seems that we're off into specialty solders for research projects - I see references to Aluminum being used (692 C melting point), though I imagine that's hard to work with (and how long will it last?). I do see a recent https://share.sandia.gov/news/resources/news_releases/wells_alloy/ of a cheaper solder of gold-silver-germanium which may fill the gap (ceiling of 350 C) - which if it does take off commercially would get COTS printed circuit boards right on the edge of being useful for a Venus mission with minimal cooling.

Also, figured I'd throw in some references to some off the shelf ICs that I found while looking into this - I see references from TI for a http://www.ti.com/lit/ml/sgzb012/sgzb012.pdfrated at up to 250 C (and down to -55 C). Honeywell claims they have an http://www.honeywell.com/sites/servlet/com.merx.npoint.servlets.DocumentServlet?docid=D68327A99-8E8D-E47E-7296-3298F97A9008 that is rated for 5 years operation at 225, and that their max temp is close to 300 C.

Amazing how far they've come in the past decade.

EDIT - and it may be moving a lot farther. Just found this http://sbirsource.com/sbir/awards/141414-high-temperature-smart-sensor-for-downhole-logging-and-monitoringto United Silicon Carbide to demonstrate an electronic sensor package for downhole operations that runs at 500C (!). Based off the linked abstract, they were able to demonstrate a working package...

Posted by: stevesliva Apr 8 2013, 03:56 PM

Flash Memory would be vital-- avoids mechanical storage:
http://www.ti.com/ww/en/hirel/high_temp_flash/index.shtml?DCMP=hirel-htflash-en&HQS=hirel-htflash-bti-en

Posted by: Robotbeat Apr 8 2013, 04:30 PM

QUOTE (djellison @ Apr 8 2013, 07:32 AM) *
Yes it is. Not all spacecraft can, should or must carry cameras. Would it be nice to take a more modern imaging suite to the surface of Venus? Obviously.

There is still huge quantities of science to be done without one, however.

It'd be useful to have a camera even for just a few minutes (during descent and on the surface) for situational awareness. It just needs to take a few pictures then can burn up. It would help tremendously to know exactly where on the surface of Venus your lander landed and what sort of soil or rock you landed on. Not needed for the long-term, though, like temperature, pressure, wind speed, and seismograph measurements would. A disposable camera is a good 80/20 solution for a lander (it's difficult to keep a camera cool, since heat can travel more easily through windows, for instance).

I suppose an old tube-style camera may be workable at high temps.

Interesting about the DOE electronic sensor package at 500C...

And when you're talking about 350+C, the term is usually "brazing" not soldering. But yeah, the non-active portions of the circuit become basically just as difficult at these temps...

Posted by: tasp Apr 8 2013, 05:43 PM

Don't know specifically about vacuum tube cameras (iconosocope I believe is the archaic term, LOL) in high heat, but vacuum tubes in general have a problem with high temperatures, surprisingly enough.

Despite the vacuum tube cathodes being strongly heated during operation (and that's why we used to wait for things to warm up before they would work), the anodes (which tubes need too) cannot be too hot. Going back 40 years in my schooling, I think the problem is secondary emission at high temp on the anode. The tube won't work right (or at all) if the anode is as hot as the cathode, and performance decreases as the temperature difference between anode and cathode decreases.

Solid state electronics as noted above are the best bet. Amazing the advances they have made in this regard.

A camera at these temperatures, even neglecting the electronics, is a fussy thing. having it stay in focus when that hot since the housing will likely expand and move everything. Lens coatings, seals, chemical attack from the corrosive atmosphere, etc. this is a tough challenge all the way around.

You'd also not want too much IR sensitivity in the image pickup or it would be swamped with it!!

Posted by: centsworth_II Apr 8 2013, 05:53 PM

Why is everyone talking about cameras on Venus like it's never been done?


http://photoshopnews.com/2006/09/12/old-soviet-images-of-venus-yield-fresh-surprises/

Posted by: Gsnorgathon Apr 8 2013, 06:05 PM

I'm guessing folks are thinking of design for long-term survival. A camera that lasts a few hours is a bit easier than one that might last long enough to see sunrise on the morning following the landing. (And wouldn't that be something?)

Posted by: Holder of the Two Leashes Apr 8 2013, 08:42 PM

No roving. Probably very little change in local weather. Changes in shadow patterns on the ground over the course of weeks, but how likely is it you would see anything else different in the landscape in the short term? We really don't know for sure.

I'd say two highly detailed 360 pans in color, offset for 3D (raising or lowering the camera a bit), each pan transmitted twice, and maybe if you get the seismometer emplaced quickly enough, a quick parting shot of that. You're good to go and the camera can fry.

Posted by: siravan Apr 8 2013, 10:38 PM

I think it is unreasonable to expect a full fledge high-temperature computer with tons of flash memory; at least early on. The more likely system would be something akin to the late 1960s or early 70s technology (say Voyager style). One solution is to have most of the telecommunication systems and memory and command handling in a separate orbiter (which of course uses regular electronics), which then commands the lander in realtime and records the data without need for much memory in the lander. The orbiter could be in a low polar orbit and can probably communicates with the lander 10 minutes every 90 minutes or so.

Posted by: tasp Apr 9 2013, 02:44 AM

For instance, the longer the camera lasts, the longer the focal length you can have on the camera (assuming a scan platform or a moving mirror of some kind).

The idea being, you have more time for more pictures, so a longer focal length gets you higher resolutions further from the probe. You'd want the time available (indefinite would be GREAT!) and the data rate available for the camera system to be utilized in sending as many pixels as possible of the area the probe lands in. Probably too much to hope for that the probe could analyze the pictures and aim for 'interesting' rocks or hills/mountains in the distance. So the probe should attempt to mosaic the entire area. (maybe a simple filter might be possible, even analog techniques might be useful. For instance, a photo of sharp angular details will have more high frequencies in an analog readout of the camera than will a photo of an area with rounded/soft forms. Presumably the sharp angles pictures would be more interesting)

Also should factor in transmission efficiency of the atmosphere, a hazy or dusty area (assuming areas on Venus vary in these details) would limit how much detail could be recorded at a distance.

Colorimetry will be a little different. We already know from the color filters used in the Soviet era that there is essentially no blue or violet light at the surface. Color analysis will be confined to red thru ~green. Also, viewing the surface in IR will be hindered at wavelengths corresponding to the ambient temperature, an IR camera won't record much detail in that band, nor at longer wavelengths. I don't know about polarized IR, maybe somebody knows if that has any practicality in this tough environment?

Posted by: DFinfrock Apr 9 2013, 03:00 AM

QUOTE (siravan @ Apr 8 2013, 10:38 PM) *
The orbiter could be in a low polar orbit and can probably communicates with the lander 10 minutes every 90 minutes or so.


How difficult would it be to park a satellite in a geostationary orbit for full-time communication with a lander? Would it require too much fuel to achieve such an orbit?

Posted by: tasp Apr 9 2013, 04:00 AM

The rotation period for Venus is sooo long . . .

How long is it ???

It's Hill Sphere isn't big enough for a geostationary (Venusostati, whatever) satellite!!


biggrin.gif

Posted by: tasp Apr 9 2013, 04:05 AM

However, there are alternatives.

For folks with Sirius satellite radio (to cite a terrestrial example of something you might have), the satellites are in highly elliptical polar orbits, with their high points over the northern hemisphere. This means those satellites spend very little time over the south pole, but quite a bit over the north pole (but at a great altitude)

So if you had a probe on the surface, and it was anticipated to last long enough for this to matter, you might want to put it poleward and have an orbiter in a path similar to the Sirius radio satellite.

{BTW, Sirius did not invent that technique, the Soviets used it extensively for many years prior}

Posted by: stevesliva Apr 9 2013, 05:42 AM

QUOTE (siravan @ Apr 8 2013, 05:38 PM) *
I think it is unreasonable to expect a full fledge high-temperature computer with tons of flash memory; at least early on.


Why? Once you have ICs working at your target temp, making them small/highly integrated is something we've figured out how to do really, really, well in the past 40 years since Voyager was state-of-the-art. Sure, you may be able to demonstrate a discrete component system at 600C while ICs only work at 250C. The thing is, though, once you have the basic IC components working at your target temp, I think it's entirely reasonable to assume you'll have a very competent microcontroller with decent volatile storage. Nonvolatile storage might have a different temp spec, but all that means is the power has to be on.

Given those 40 years since Voyager, I'm not sure that with the skills we've gained in highly integrated circuits that we're ever going to have any high-temp technology that's "IC" without it being good enough to make a pretty complex integrated microcontroller. Either you have a lander with relatively unprogrammable instruments transmitting all data in real time-- and perhaps that would be really cool if it was long-lived-- or you have enough integration to do C&DH on the lander. It's really hard to imagine an in-between.

Posted by: siravan Apr 9 2013, 11:51 AM

Making an IC is the difficult part. It is not clear if you have a high temperature semiconductor, it can be turned into an IC easily. I'm no expert by any mean, but my understanding is that the reason silicon ICs exist and work great is the favorable crystalline structure of Si and the existence of insulator bases that integrate well with Si (such as SiO2 and, in case of radiation hardened electronics, Al2O3=sapphire). I'm not sure if silicon carbide shares these favorable features. I guess that the earliest systems will be mainly based on discrete elements and few low density ICs.

Posted by: dtolman Apr 9 2013, 02:07 PM

They've already started making Silicon Carbide IC's - so the barrier has been breached. My understanding is that the problem is making them durable for long term use.
This http://www.grc.nasa.gov/WWW/SiC/publications/PSSA-JFETICs09.pdf is about 4 years old, so the state of the art has advanced since then, but I found it to be a good overview.

Posted by: stevesliva Apr 9 2013, 04:56 PM

QUOTE (siravan @ Apr 9 2013, 06:51 AM) *
I'm not sure if silicon carbide shares these favorable features. I guess that the earliest systems will be mainly based on discrete elements and few low density ICs.


That sort of gets at my point-- I tend to think if you have the technology to get reliable "low density ICs" at your spec high temp, you'll very soon have enough VLSI to get a damn decent microcontroller. If it involves wafers--SiC, sapphire, whatever-- and lithography, they sort of hit the ground running these days. Technologies mature with VLSI as a given. I tend to agree that if other technologies aren't mature, the board those ICs go on might be a trip back to times when things were handmade rather than on PCBs, but again, just my opinion, is that if you have anything proven in manufacture that you can call an IC, lithography is probably going to allow you to have a microcontroller with an instruction cache and data cache. Technologies exit the lab with that level of integration. [It's my opinion that] When there is a facility that starts making qualified SiC IC's, it will have the ability to enable microcontrollers from the get-go, so it's fun but not necessary to imagine system architectures that don't need LSI.

Posted by: Robotbeat Jun 11 2013, 12:51 PM

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.

Posted by: JRehling Jun 11 2013, 04:50 PM

I wonder if a "two-brain" strategy might make sense for a Venus lander. One that has sensitive parts and stays alive for hours, then dies as expected, and one that has tough, robust, vacuum-tube-style electronics that transmits low-bandwidth data for months. In particular, if that could break down into imaging and gas chromatography that is done during descent and just after landing -- perhaps a laser-induced spectrometer -- and then long-term seismological monitoring.

It's encouraging to think that improvements in electronics might make this mission cheaper one day, if not now. The last and only time a US mission transmitted data from the surface of Venus was 1978. That's astonishing.

Posted by: Robotbeat Jun 12 2013, 05:13 PM

Indeed, I had thought of such an approach. It makes certain things a lot easier, for instance the camera and as you said some kind of spectrometer. You'd also want probably a pressure probe, temperature probe, and anemometer (wind speed), too, to determine if seismic events are really just caused by the wind.

Posted by: stevesliva Jun 13 2013, 05:37 AM

QUOTE (Robotbeat @ Jun 11 2013, 08:51 AM) *
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.

Posted by: tasp Jun 13 2013, 05:48 AM

I'm wondering if something like a corner reflector might be made of some high temperature (and chemical) resistant material, that could have it's dielectric properties, or reflection angle, (or something) that varies in a predictable way with temperature and or pressure.

The reflector could be dropped and then illuminated with a radio signal from an orbiter, and the return echo would be phase modulated, or whatever the device can be made to do to alter the signal, and then you would have a point on the surface that could me monitored for one or a very few parameters, for as long as the orbiter lasted.

A reflector on an anemometer would frequency modulate the reflection (if done properly) in proportion to the wind velocity. Two such reflectors on a bimetallic arm on a pivot would introduce a bias to the wind signal that would be temperature related.

Might be a way to get some very basic long term data from a few interesting sites. Just need to have a very simple, and robust device in the right location.

Posted by: Robotbeat Jun 13 2013, 12:56 PM

QUOTE (stevesliva @ Jun 12 2013, 11:37 PM) *
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.

Posted by: stevesliva Jun 13 2013, 09:24 PM

QUOTE (Robotbeat @ Jun 13 2013, 08:56 AM) *
I think you're missing something, here... With high-temp electronics, we don't have access to Moore's Law.


Yeah, but you have access to anything that trickles down from the silicon ecosystem. It's unlikely that you're going to end up with an IC made on a 50mm wafer with 10um geometries. Something like SiC wafers with W wiring... that will still get proven in a 150mm or 200mm research fab at submicron geometries. They aren't reinventing everything from the 1970 level.

The funding is otherwise a huge issue. But I think automotive applications will help. And for whatever reason, it seems LED makers are interested in SiC.

Posted by: Robotbeat Jun 17 2013, 01:12 PM

Power draw is a huge issue, because you can't do CMOS. Memory draws a ton of power, so even if you can build a big chip, you would need a very large power source. Which is a pretty big problem on the surface of Venus, where very little light gets through, your cold end for a heat engine is already nearly as high as the hot end for MMRTG.

Posted by: dtolman Jun 17 2013, 09:13 PM

Doesn't seem to me that high temperature memory is that far behind IC's. As someone mentioned before, TI is selling anhttp://www.ti.com/ww/en/hirel/high_temp_flash/index.shtml?DCMP=hirel-htflash-en&HQS=hirel-htflash-bti-en currently. I've seen some research documents that refer up to 300 C memory units in lab tests being run now, so the OTS max temperature should keep pushing up over the next few years.
EDIT: and I now see this http://www.raytheon.co.uk/capabilities/proven/semiconductor/index.html by Raytheon that they are working on a SiC based CMOS rated at 450C.
So why can't we do CMOS on Venus?

This might be of interest -http://www.netl.doe.gov/technologies/oil-gas/publications/EPreports/NT42947_TSA.pdf on the challenges (and solutions) for building 250 C rated ICs, that goes into memory solutions as well.
--
IC related Bonus - found this http://www.grc.nasa.gov/WWW/SiC/publications/PSSA-JFETICs09.pdf. Think I missed this on my last review of papers on high temperature ICs.

Posted by: Robotbeat Jun 18 2013, 12:18 PM

QUOTE (dtolman @ Jun 17 2013, 03:13 PM) *
Doesn't seem to me that high temperature memory is that far behind IC's. As someone mentioned before, TI is selling anhttp://www.ti.com/ww/en/hirel/high_temp_flash/index.shtml?DCMP=hirel-htflash-en&HQS=hirel-htflash-bti-en currently. I've seen some research documents that refer up to 300 C memory units in lab tests being run now, so the OTS max temperature should keep pushing up over the next few years.
EDIT: and I now see this http://www.raytheon.co.uk/capabilities/proven/semiconductor/index.html by Raytheon that they are working on a SiC based CMOS rated at 450C.
So why can't we do CMOS on Venus?

This might be of interest -http://www.netl.doe.gov/technologies/oil-gas/publications/EPreports/NT42947_TSA.pdf on the challenges (and solutions) for building 250 C rated ICs, that goes into memory solutions as well.
The tech that works up to 250C is not usable to the ~500C needed for Venus (it /can't/ work, the tech simply stops producing gain at that point). The Raytheon CMOS SiC stuff is interesting, but a lot of this stuff has been "talked about" for a good couple decades without significant progress towards something actually usable. Goes on the list, though!
QUOTE
IC related Bonus - found this http://www.grc.nasa.gov/WWW/SiC/publications/PSSA-JFETICs09.pdf. Think I missed this on my last review of papers on high temperature ICs.

Ah, yes, Philip Neudeck... One of the people I've talked to on trying to see what will and won't work. This field is so small that a lot of the references are by the same people. Some people are really optimistic about getting a usable large-scale IC in a short time, others are quite pessimistic. The consensus currently is that memory is a really hard problem. You need Megabytes of memory, not just the 100 bits that might be doable in the next 5 years.

(And Mike K, also one of the authors of that paper, is probably the most interesting person I've ever met at NASA. He's on my list of most favorite people ever.)

And the question isn't about physical impossibility or not, but on state of the technology... If you want a mission that actually /happens/ and isn't a paper study, we can't be happy with a TRL of "well, physically it's possible." The people who decide whose mission to build will reject that every time.

...That said, prove me wrong!

Posted by: dtolman Jun 18 2013, 02:30 PM

I think you're being pessimistic. The state of the art for commercial tech is moving to a 500C package. Automotive want it, and drillers need it - with immediate potential sales in the 10K-100K annual range, and potentially in the Millions if it becomes standard in engines, there's enough sales carrot to push research. NASA can wait, and in 5-10 years use COTS equipment as the basis of a Venusian lander.

The question of pushing existing tech into the 500C range is interesting - found http://publica.fraunhofer.de/documents/N-178272.html that claims they were able to get existing Silicon-on-Insulator EEPROM cells working at up to 450C in a lab, well beyond the ~200C they are rated for now. That bodes well for getting memory working at venusian ranges in the near-future, rather the nebulous "5-10 years from now" that never arrives.

As for existing tech - there definitely isn't anything outside of a lab that will work over long durations, but short duration missions are possible now with existing tech from what I can see. For example, http://www.odplegacy.org/PDF/Operations/Engineering/Logging_Tools/GRC.pdf that is rated at 4-5 hours at 400C. While the sensors in this particular unit may be of limited interest*, my point is that they can get modern electronics to last long enough to return useful data from the upper elevations of the highlands for a few hours - now.

EDIT * - thinking about it, measuring temp/pressure/motion at a lot of locations would probably be useful. Wonder how expensive it would be to equip borehole sensor packages with a transmitter and a parachute, and dump a bunch across the highlands of Venus? Gotta be cheaper than doing it from scratch...

Posted by: Robotbeat Jun 18 2013, 03:36 PM

QUOTE (dtolman @ Jun 18 2013, 08:30 AM) *
...

EDIT * - thinking about it, measuring temp/pressure/motion at a lot of locations would probably be useful. Wonder how expensive it would be to equip borehole sensor packages with a transmitter and a parachute, and dump a bunch across the highlands of Venus? Gotta be cheaper than doing it from scratch...

I've thought of the same thing... The issue is partially that if you /actually/ press the borehole guys about operation at 460C, they dither a bit. They aren't nearly so optimistic as their websites claim.

I hope you're right about me being pessimistic

Posted by: dtolman Jun 18 2013, 06:36 PM

Its a good thing that Ishtar Terra has temperatures that drop as...low... as ~380 (Maxwell Mons - +11km above surface), and averages "only" 420 or so at its average height of ~+5km.
Gotta start somewhere on Venus, and Maxwell Mons and the other high peaks around Ishtar Terra might be a good place to start with existing tech.

EDIT: Another project for ~450 C operation, through the DoE:
http://www4.eere.energy.gov/geothermal/projects?filter[field_project_technology][0]=%2214%22
http://www4.eere.energy.gov/geothermal/sites/default/files/documents/gtp_pr2012_basetechtools.pdf (from last year - final results in the forthcoming 2013 report) indicates they were able to get data back from a 450C environment (vacuum flasked electronics).

Posted by: Robotbeat Jun 18 2013, 07:22 PM

QUOTE (dtolman @ Jun 17 2013, 03:13 PM) *
...
EDIT: and I now see this http://www.raytheon.co.uk/capabilities/proven/semiconductor/index.html by Raytheon that they are working on a SiC based CMOS rated at 450C.
So why can't we do CMOS on Venus?
...
IC related Bonus - found this http://www.grc.nasa.gov/WWW/SiC/publications/PSSA-JFETICs09.pdf. Think I missed this on my last review of papers on high temperature ICs.

A quote from the NASA paper: "While silicon electronics experience clearly demonstrates that complementary MOSFET (CMOS) technology is desired for implementing integrated circuits, development of the necessary high electrical quality gate-insulators that would enable long-term 500 C operation of SiC MOSFETs will likely prove elusive for many years to come [21]."

Posted by: stevesliva Jun 19 2013, 06:08 AM

^ Yeah, JFETs don't need that gate insulator. They also only had n-type, so of CMOS, they have MS. Nothing people haven't worked around in the past to make large devices. But, unfortunately, at the 10um geometries I poo-pooed earlier and with really low reliability, which isn't something that's easy to work around. Infinite money and access too commercial dev fabs, though... sigh.

Posted by: dtolman Jun 19 2013, 02:49 PM

Sorry to keep shining rays of optimism here, but circling back to Raytheon's claims, it looks like its more than pie-in-the sky. Here is a 2012 paper describing testing they did with a SiC CMOS at 400C:
http://www.raytheon.co.uk/rtnwcm/groups/rsl/documents/content/rsl_semi_high_temp_article.pdf.

So components that could theoretically function at ambient temperature on the (high plateau/peak) surface of Venus are in labs now. Assuming they're reliable, its just a question of time before they're commercially available.

Finally - if you want something to add to your reading list, I stumbled upon this http://books.google.com/books?id=MXxbv4pzgbYC&pg=PA228&lpg=PA228&dq=raytheon+high+temperature+sic&source=bl&ots=m9IA9RkPQ9&sig=DZtkMWHmQ-VxnoWg0_fORROiFyI&hl=en&sa=X&ei=lsLBUcmMOIuO0QHPyIHgCA&ved=0CFoQ6AEwBDgK#v=onepage&q=raytheon%20high%20temperature%20sic&f=false

Posted by: Robotbeat Jun 19 2013, 02:57 PM

dtolman:
Ah, behold the motivating power of proving someone wrong on the Internet!

Thank you. smile.gif The Raytheon paper is quite useful to me. http://www.raytheon.co.uk/rtnwcm/groups/rsl/documents/content/rsl_semi_high_temp_article.pdf.

(Still, power consumption at temperature is pretty high...)

Posted by: Bill Harris Jun 21 2013, 07:00 PM

I'd suspect that the solution will come from the emerging technology of non-silicon transistors with nanoscale materials.

Beyond Silicon: Transistors Without Semiconductors
http://www.sciencedaily.com/releases/2013/06/130621121015.htm

--Bill


Posted by: Robotbeat Jun 25 2013, 12:25 PM

QUOTE (Robotbeat @ Jun 19 2013, 08:57 AM) *
dtolman:
Ah, behold the motivating power of proving someone wrong on the Internet!

Thank you. smile.gif The Raytheon paper is quite useful to me. http://www.raytheon.co.uk/rtnwcm/groups/rsl/documents/content/rsl_semi_high_temp_article.pdf.

(Still, power consumption at temperature is pretty high...)

The Raytheon paper makes no mention to how long it can last at 400C. I've heard that the insulating layer doesn't last terribly long at those temperatures. The fact that no mention is made of length of time is a bad sign.

Posted by: tasp Jun 25 2013, 03:27 PM

Thanx Robotbeat for mentioning the power consumption, it brings up another concern.

A hypothetical device on Venus operating at the high ambient temperature there will not be 100% efficient (nothing is anywhere), and it will warm above ambient temperature and need to dissipate some power into the environment.

It's another challenge, the device will need a heat sink (or active cooling, erf) and it makes the situation more complex, like it's not difficult enough already.

The material of the heatsink will need to be compatible with the environment and function properly.

Posted by: djellison Jun 25 2013, 04:11 PM

QUOTE (tasp @ Jun 25 2013, 07:27 AM) *
The material of the heatsink will need to be compatible with the environment and function properly.


The material of every spacecraft needs to be compatible with the environment it's sent to and to function properly.


Posted by: SpaceListener Jun 25 2013, 08:48 PM

If the chamber where it is stored electrical instruments has a static insulation and the air is emptied, the internal temperature would be lower than outside? I think the heat sink in Venus is not useful because the atmosphere is warmer outside than the inside of chamber.

Posted by: dtolman Jun 26 2013, 03:45 PM

If you can get electronics running at ambient, just leave them exposed* and cool them off with a fan. After all - thats what we do with PCs here when they run hotter than the atmospheric temp smile.gif

On a more realistic note, if memory serves, the latest surface proposals were nuclear powered and cooled with a Stirling Cycle heat engine. Of course those missions anticipated a 200 C interior and 500 C exterior - a 300 C differential. I imagine the power requirements for running the heat engines would be lower if you can get the electronics closer to 400 C and a 100 C - or smaller - differential, and more than make up for the hotter electronics.

*Now we just need high temperature, acid rain resistant electronics

Posted by: siravan Jun 26 2013, 05:59 PM

QUOTE
Now we just need high temperature, acid rain resistant electronics


Not much of acid rain on the surface (sulfuric acid evaporates before reaching ground), but high preesure-hot CO2 is highly corrosive and problematic. It seems that the only thing "easy" for a venus lander is the actual EDL. Parachutes to around 20-30 km, then free fall all the way down.

Posted by: Robotbeat Jun 26 2013, 09:09 PM

QUOTE (dtolman @ Jun 26 2013, 10:45 AM) *
If you can get electronics running at ambient, just leave them exposed* and cool them off with a fan. After all - thats what we do with PCs here when they run hotter than the atmospheric temp smile.gif

On a more realistic note, if memory serves, the latest surface proposals were nuclear powered and cooled with a Stirling Cycle heat engine. Of course those missions anticipated a 200 C interior and 500 C exterior - a 300 C differential. I imagine the power requirements for running the heat engines would be lower if you can get the electronics closer to 400 C and a 100 C - or smaller - differential, and more than make up for the hotter electronics.

*Now we just need high temperature, acid rain resistant electronics

Indeed, those actively cooled mission proposals are what my mentor has been working on. But the power requirements are pretty big for active cooling, since your heat dump is so hot. That means completely custom high-power radioisotope... Flagship class funding requirement, but at best a Discovery-class risk level, so unlikely to fly before I retire.

But one good thing about Venus's atmosphere is that because it's so dense, it should carry /extra/ heat away rather well, better than on Earth. Of course, the problem is that you have to start out at ~450C or so....

Also, although there is no acid rain droplets on the surface, you do have the products of dissociated sulfuric acid, so corrosion is still a problem. But a better problem to have than the incredibly high temperatures.

Posted by: dtolman Jun 27 2013, 05:14 PM

Thinking about it, perhaps if the goal is electronics that work in near-ambient temperatures, then the cooling schemes where they need to refrigerate the electronics is all wrong. If the goal is to get to 400+C rated electronics, than a totally different cooling system will be needed. Once you get to the point where the electronics are hotter than the outside air, which at 400 C rated electronics might be true for highland landings, you can switch to less exotic methods - passive radiators, or some kind of liquid cooling (sodium?).

I don't know much about more passive cooling techniques, but I imagine that a sodium (or some other high temperature liquid) cooled electronics bay would be a lot cheaper, lighter, and require less power than a Stirling Engine.

Posted by: Robotbeat Jun 29 2013, 06:15 AM

QUOTE (dtolman @ Jun 27 2013, 12:14 PM) *
Thinking about it, perhaps if the goal is electronics that work in near-ambient temperatures, then the cooling schemes where they need to refrigerate the electronics is all wrong. If the goal is to get to 400+C rated electronics, than a totally different cooling system will be needed. Once you get to the point where the electronics are hotter than the outside air, which at 400 C rated electronics might be true for highland landings, you can switch to less exotic methods - passive radiators, or some kind of liquid cooling (sodium?).

I don't know much about more passive cooling techniques, but I imagine that a sodium (or some other high temperature liquid) cooled electronics bay would be a lot cheaper, lighter, and require less power than a Stirling Engine.

If you can get the electronics to work at just above ambient /reliably for a long time/, then cooling isn't much of a problem in Venus's dense atmosphere. But that's a pretty big if. And the Raytheon stuff isn't "rated" for 400C, it's been operated there for some (presumably quite limited) finite period of time. A problem with the highlands, though, is that it's not really a good place to land something like a seismometer because it looks much rockier than most of the Venera landing sites.

Posted by: Xcalibrator Sep 9 2013, 02:31 PM

QUOTE
A RFI http://go.usa.gov/jtdJ has been issued in FEDERAL BUSINESS OPPORTUNTIES for a new prize competition being considered by NASA. As currently envisioned the Extreme Environments Challenge would focus on finding innovative solutions to the problems surrounding the survival and operations of scientific probes in extreme environments, such as on the surface of Venus where temperatures approach 500 C, the atmospheric pressure is about 90 times that at the Earth’s surface, and the atmosphere is corrosive. The approach being considered would entail a series of competitions that would focus on 1) electronics and mechanisms, and 2) thermal management, and 3) power with a culminating systems integration competition.


Sorry for the very late notice (RFI responses are due tomorrow); it took a couple weeks to get validated to post here after I registered.

Posted by: dtolman Nov 15 2013, 05:01 PM

So when can we find out what the result was for the RFI?

---

Of possible interest to those following high temperature electronics news:
A new 230 C rated capacitor http://powerelectronics.com/passive-components/hermetically-sealed-smd-tantalum-capacitor-series-230-c-rating AFAIK this is significantly higher than other commercially available capacitors which previously struggled to hit the 200 C mark. I've read a few papers which suggest the ceiling for this kind of technique is around 250-260 C, so still room for improvement.

-
For anyone doubting the commercial pressure/demand for hitting 300+ C, a http://www.offshore-mag.com/articles/print/volume-73/issue-11/departments/drilling-production/spe-sets-attendance-record.html. Readers here might be amused at the 3rd paragraph of the quoted section (below) - looking to commercial sectors to push high temperature electronics while they look back at NASA to push it forward. Perhaps there are some synergistic opportunities waiting out there? smile.gif

QUOTE
Already, there are wells today with parameters than cannot be measured because bottomhole temperature exceeds the operating limits of any known sensors. Short-term measurements, like those made with wireline tools, fare better than long-term ones, like those made with LWD strings that must withstand high bottomhole temperatures for hours or days. And production sensors, like downhole gauges, must be able to operate flawlessly for weeks at a time or longer. The current record for the most robust downhole pressure and temperature gauge performance is 410F (210C) for 15 days at 16,754 ft (5,107 m). Unfortunately, this record was set far above the well's total depth, leaving the operator to extrapolate the data to estimate actual bottomhole pressure and temperature. Along with electronic circuitry, batteries in particular are regarded as one of the weakest links in high-pressure/high-temperature technology.

Perhaps the most promising frontier of potential energy is the geothermal one. The prospect of being able to capture geothermal energy and convert it to electrical energy has been a long-time dream. But early experience in geothermal exploration shows that bottomhole temperatures of 600F (316C) or more can be expected. If we expect to operate logging and drilling tools at these temperatures, we need a breakthrough in electronics and sealing technology. We need to be able to make our electronic components out of new, more robust materials that can take the heat. We need seals that can contain superheated steam without failure.

An excellent asset has been the deep space exploration program. Temperature conditions on Mars, for example, can be harsh. If the oil and gas industry can adapt some of the technology that has enabled long-term equipment viability in a Mars Rover, it might be able to extend its reach. But the space program has experienced severe budget cutbacks. Will it be able to sustain its first-class R&D programs?

Posted by: dtolman Feb 4 2014, 02:25 AM

Just 3 months later a series of http://www.kemet.com/kemet/web/homepage/kechome.nsf/weben/Hi%20Temp%20Ceramic are now on the market.

--

I had mentioned a DoE high temperature project last year. http://www4.eere.energy.gov/geothermal/sites/default/files/documents/self_consuming_packer_peer2013.pdf, though it seems to only focus on a new Epoxy formulation tested to 315C.

--

The RFI xCalibrator mentioned was part of http://www.nasa.gov/directorates/spacetech/centennial_challenges/index.html#.UvBPHvuUewc, but I'll be damned if I can find anything on it at the site.

Posted by: stevesliva Jul 18 2014, 10:52 PM

GE and New York State are moving from 100mm to 150mm wafers for SiC:
http://www.gereports.com/post/91863830615/chipping-in-tech-from-ge-labs-could-make-planes
https://www.governor.ny.gov/press/07152014NY-Power-Electronics-Manufacturing-Consortium

One caveat is that the NYS Semiconductor research efforts generate a lot of PR hotair. I'm not even sure GE is the leader in SiC integration. Nonetheless, the fact that the industry's already moving to 6" wafers for SiC does sort of reiterate my earlier point that devices will be VLSI from the get-go with no interregnum period where you have to cobble CPUs together from multiple discrete few-T chips.

Posted by: dtolman Jan 9 2015, 03:02 AM

Its been a while, but there continues to be a steady drumbeat of every higher temperature commercial components that inch closer to (or even surpass) Venusian temperatures.
Some examples:
http://www.compoundsemiconductor.net/article/94862-ge-researchers-develop-250degc+-sic-transient-voltage-suppressor.html (Surge protector)
http://www.engineering.com/DesignerEdge/DesignerEdgeArticles/ArticleID/8932/High-Temperature-Elastomers-in-Oil-Gas.aspx (think, Vulcanized Rubber), rated to 450 C
http://www.electronicsweekly.com/news/manufacturing/kyocera-pushes-htcc-packaging-1000c-2014-09/ (!)

http://electroiq.com/chipworks_real_chips_blog/2014/12/08/iedm-2014-preview/#comments mentions a talk on a diamond MOSFET (transistor) that worked in temps ranging up to 400 C (http://www.his.com/~iedm/program/session/s11.pdf!).

A http://www.ttiinc.com/object/me-slovick-20140612.htmlnote the demand for 200-250 C rated components is growing - with ceramic, Tantalum, and film based capacitors competing in that temperature range.

Posted by: elakdawalla Jan 9 2015, 04:44 PM

That's cool. Asking in near-perfect ignorance: what has to happen before component like these can actually be used in deep-space applications? I imagine the process of certifying their reliability is not a quick one.

Posted by: mcaplinger Jan 9 2015, 06:25 PM

QUOTE (elakdawalla @ Jan 9 2015, 09:44 AM) *
what has to happen before component like these can actually be used in deep-space applications?

A full-up system operating in the expected mission environment (temp, pressure, etc.) for at least 3x the desired mission life would be an absolute minimum.

Posted by: marsbug May 5 2015, 03:14 PM

http://news.uark.edu/articles/27519/nsf-grant-will-further-development-of-high-temperature-integrated-circuits

Posted by: dtolman May 11 2015, 08:16 PM

A few items of interest:
Another new 250C tested commercial capacitor (from the graphs, might be able to perform briefly above 250). Also shock tested to 500G. http://www.edn.com/design/components-and-packaging/4439354/Going-deep--Capacitors-take-the-heat-of-extreme-down-hole-drilling contains a nice guide to the commercial state of the art for downhole high-temp/high-pressure rated electronics. This caught my eye as useful to know:
The UK Energy Institutes Model Code Of Safe Practice originally standardized a definition for High-Pressure/High-Temperature (HPHT) wells, as having undisturbed bottom-well temperatures above 149C and needing pressure-control equipment with a rated working pressure of over 69MPa (10,000 psi). These limits are no longer adequate to distinguish todays most extreme wells, and new definitions are emerging. Although yet to become widely standardised, the ultra High-Pressure/High-Temperature (uHPHT) category now covers temperatures from 204C to 260C and pressure from 139MPa to 241MPa, while extremely High-Pressure/High-Temperature (xHPHT) refers to temperatures above 260C and pressures above 241MPa.

So guess xHPHT is the new google search term to enter in if you're looking for commercial Venusian survivable equipment smile.gif
Entering it into google shows a small, but growing list, of xHPHT research and products - this one caught my eye:
http://www.quartzdyne.com/newsletters/october-2014.html It reports that the new ASIC has survived over 1,000 hours testing at 275C. Gotta wonder at what point COTS high-temp equipment doesn't require a nuclear reactor to cool anymore for a viable Venusian lander. More information on their high temperature IC development http://www.quartzdyne.com/pdfs/IME2014-newsletter.pdf

Not specifically high temperature, but
http://www.ttiinc.com/object/me-zogbi-20150424.html - which I mentioned earlier this year as a future technology with high temperature thresholds.

Posted by: hendric May 12 2015, 08:14 PM

Very interesting stuff, can't wait to see a rover on Earth's sister planet!

Posted by: JohnVV Jun 3 2015, 03:30 AM

new(ish) carbon nanotube ram chips that can withstand 300C for a LONG time
http://hardware.slashdot.org/story/15/06/02/2056228/fabs-now-manufacturing-carbon-nanotube-memory-which-could-replace-nand-and-dram

http://www.computerworld.com/article/2929471/emerging-technology/fab-plants-are-now-making-superfast-carbon-nanotube-memory.html

Posted by: dtolman Aug 1 2015, 01:37 AM

NASA has http://www.semiconductor-today.com/news_items/2015/jul/nasa-ozark_280715.shtml to design 500c rated SiC components for a future Venus surface mission.

EDIT: While I'm looking at the subject...
http://phys.org/news/2015-07-polymer-energy-higher-temperatures.html. High Temperature Capacitors is one specific application mentioned in the article.

Posted by: nprev Aug 15 2015, 04:06 PM

http://spectrum.ieee.org/tech-talk/aerospace/robotic-exploration/nasa-commissions-ultra-high-temp-chips-for-venus-landsailing-roveron Venus electronics & applications. First I've heard of the concept rover mentioned there.

Posted by: hendric Aug 17 2015, 08:30 PM

Wow, an imager running at 600*F? Even if UV only that is one hell of an accomplishment. Hazcams via blacklight!

Posted by: Habukaz Sep 3 2015, 09:39 PM

Meta-news:

QUOTE
Inside the 14-ton, stainless steel, 3- by 6-foot chamber, temperatures can soar beyond 900 degrees Fahrenheit, hotter than the surface of Venus. At the same time, pressure can reach nearly 100 times the weight of Earth’s atmosphere at sea level.

[...]

In addition to scientific research, GEER also will be used to test sensors and equipment, such as high-temperature electronics, that one day could enable long-duration surface missions to Earth’s mysterious sister planet.


http://news.discovery.com/space/hell-on-earth-nasa-recreates-venus-extreme-atmosphere-150902.htm

EDIT: see it has already been mentioned - guess it is ready now?

Posted by: colin_wilson Jun 16 2016, 09:56 AM


Swedish tech lab KTH is working to develop high-temperature silicon carbide electronics for ambient temperature operation at the surface of Venus.

https://www.kth.se/blogs/wov/
https://www.kth.se/blogs/wov/files/2014/10/Working_on_Venus_KAW_160304.pdf

They're pretty ambitious - aiming to demonstrate digital CPUs, amplifiers, gas sensors, seismometers.

From the PDF document linked above:

"
The project started January 2014 and has eight
PhD students in the different work packages.
Our present bipolar technology has been scaled
to smaller transistors, and self‐aligned nickel
contacts have been developed. Four new
integrated circuit designs were made for
different parts of the lander electronics: CMOS
circuit test set, a 4‐bit microprocessor, RF
transistors for the radio transceiver and a
prototype pixel sensor for the imaging. Most of
these have been fabricated by the PhD students
in the KTH Myfab clean room, some are still in
progress. Preliminary testing and modeling
show operation up to 550 C, sufficient for the
Venus target. A first demonstration has been
made of capacitive inertial sensing at high
temperatures; gas sensors have been annealed
at 500 C for 300 h; photodiodes sensitive in the
near UV range (200 to 400 nm) have been tested
up to 550 C. Power sources have been
identified, and passive components like
inductors have been tested to 500 C.
"

Posted by: Explorer1 Jul 6 2016, 06:21 PM

Interesting article I found today: a Sterling engine with lithium fuel? http://www.bbc.com/future/story/20160705-the-toughest-spaceship-weve-ever-built

Posted by: Xcalibrator Aug 23 2016, 02:55 PM

ROSES-16 Amendment 25 releases the new program element C.24 https://nspires.nasaprs.com/external/solicitations/summary.do?method=init&solId=%7B7C46C02B-4ADB-BDD8-CA52-714DE026F336%7D&path=init.

The Hot Operating Temperature Technology (HOTTech) program supports the advanced development of technologies for the robotic exploration of high-temperature environments, such as the Venus surface, Mercury, or the deep atmosphere of Gas Giants. The goal of the program is to develop and mature technologies that will enable, significantly enhance, or reduce technical risk for in situ missions to high-temperature environments with temperatures approaching 500 degrees Celsius or higher. It is a priority for NASA to invest in technology developments that mitigate the risks of mission concepts proposed in response to upcoming Announcements of Opportunity (AO) and expand the range of science that might be achieved with future missions. Note that this HOTTech program element is not soliciting hardware for a flight opportunity.

HOTTech is limited to high temperature electrical and electronic systems that could be needed for potentially extended in situ missions to such environments. NASA seeks to maximize the benefits of its technology investments and consequently technologies that offer terrestrial benefits, in addition to meeting needs of planetary science. While specific technology readiness levels are not prescribed for the HOTTech program, proposers are reminded that the goal of the program is to mature technologies so they can be proposed as part of a selectable mission concept or technology demonstration to a flight AO with reduced risk. It is the responsibility of the proposer to describe how their proposed technology development effort addresses the goals of enabling or enhancing future mission capability or reducing risk and how the technology will be matured for a flight opportunity as part of an integrated system. Efforts that focus on advancing the technology readiness level (TRL) of a system composed of multiple existing technologies at various TRLs are allowed under this opportunity.

Notices of Intent are requested by September 28, 2016, and the due date for proposals is November 23, 2016.

Posted by: hendric Feb 8 2017, 08:19 PM

https://arstechnica.com/science/2017/02/venus-computer-chip/

An oscillator is a very important step in creating a full Silicon Carbide based CPU capable of operating a Venus temperatures. 1 MHz doesn't sound like much, but it is more than enough for basic analysis. The hard thing to get working is an imager - high temps mean leaky pixels. This is yet another great example of NASA dual use, with this tech being very useful for deep well operation.

Posted by: JRehling Feb 9 2017, 09:28 PM

QUOTE (hendric @ Feb 8 2017, 01:19 PM) *
The hard thing to get working is an imager - high temps mean leaky pixels.


It may be interesting for those who don't know cameras used for amateur photography of Deep Sky Objects are cooled internally, reducing the incidence of such noise. A galaxy or nebula may be roughly 1/100,000th as luminous as a planet, and cooling the camera to, say, -15C when outside temperatures are +15C can help tremendously in producing a clear image, whereas this is not needed for imaging planets.

On the surface of Venus, the luminosity isn't a problem, but the temperature is. On the other hand, another solution to this problem would be to provide passive or active cooling for just long enough to take one image, then let the camera die. Potentially, almost all of the science value would be in taking a single image as soon as possible after landing.

Posted by: algorimancer Feb 10 2017, 07:23 PM

QUOTE (JRehling @ Feb 9 2017, 03:28 PM) *
...provide passive or active cooling for just long enough to take one image, then let the camera die....

So long as the ccd-equivalent sensor doesn't degrade with the heat, active per-image cooling strikes me as feasible. I'd really like to see a rover, rather than just a fixed lander, so multiple images are important. Alternatively, I could envision something like polaroid instant film, a ccd-equivalent on something like a roll, where we get one shot per sensor, read and transmit the image, then roll to the next good sensor.

One problem (aside from heat tolerance) with current sensors is that they have a strong response in the infrared. Not such a good thing on Venus.

Has there been any progress on high-temperature imaging sensors?

Posted by: Holder of the Two Leashes Feb 10 2017, 07:33 PM

If you're using a cooled and sealed environment to house your CCD in, then it is easy enough to deal with the infrared. Just put a filter in the sealed chamber between the camera and the inner window.

Posted by: hendric Feb 13 2017, 05:33 PM

Dr Neudeck kindly forwarded me a concept study for a long-duration Venus surface station:

http://www.hou.usra.edu/meetings/lpsc2017/pdf/2986.pdf



SiC imagers have been developed for solar imaging, because they have a high rejection of infrared due to the large band-gap:

http://techport.nasa.gov/externalFactSheetExport?objectId=16616
http://techport.nasa.gov/file/15351

Imagine a wind-powered rover using UV cameras to drive across Venus, stopping to recharge using a windmill, and with UV LEDs to keep driving during the Venusian night! wheel.gif wheel.gif

Posted by: mcaplinger Feb 13 2017, 06:11 PM

QUOTE (algorimancer @ Feb 10 2017, 11:23 AM) *
One problem (aside from heat tolerance) with current sensors is that they have a strong response in the infrared. Not such a good thing on Venus.

IR cut filters are trivial. The wavelengths silicon sensors are sensitive to are in the very near IR near 1 micron, not in the thermal IR. Imaging in the near IR can be a good thing on Venus because there is less scattering from the atmosphere, at least in some bandpasses. Bottom line: no new technology required if there is some way to cool the sensor.

And we are a long way from having electronics that work at Venus ambient, let alone image sensors, this most recent development notwithstanding.

Posted by: algorimancer Feb 14 2017, 04:37 PM

It sounds like we might be able to contemplate a dumb lander, just sending some basic information like temperature, wind speed, and perhaps seismic data, as early as 5 years from now. Optimistically, maybe a rover with imager in 10-15 years. Technology is coming along. At my age, these time scales aren't too bad smile.gif

Posted by: Holder of the Two Leashes Feb 14 2017, 05:12 PM

Did anybody notice that the SiC imaging chip in question is solar blind? That means operating in a spectrum area of UV that the sun doesn't put out very much of, let alone worrying whether any of that output could make it through the atmosphere. Which means in turn that you are going to have to have some kind of powerful very short wave UV illuminator to light up the area with.

Posted by: hendric Feb 14 2017, 06:17 PM

That's not the way I interpreted the specifications. I think they meant solar-blind in the sense that they don't need special protection against the IR and visible light coming from the Sun: The sensor is inherently not sensitive to IR and visible light, and can tolerate very high operating temperatures.

mcaplinger - The abstract is really for a UV-targeted imager, not necessarily a SiC specific one. They state

"The high sensitivity of silicon CCDs and CMOS arrays in
the visible and near infrared (IR) is a liability when employing
these same arrays in the ultraviolet. As exemplified in the
Hubble telescope instruments, long wavelength blocking filters
exact a high price due to their low transmission in the ultraviolet."

So for their needs a SiC imager is better for UV sun imaging than an Si based imager + IR Cut.

I posted the link to show that SiC based imagers (not necessarily tuned for the Venus environment yet) do exist. They do point out the underlying JFET technology can tolerate 300*C temps.

Posted by: siravan Dec 5 2017, 12:36 PM

The Science journal has a new article about the recent advances in high-temperature electronics for Venus missions, especially silicon-carbide chips developed at the Glenn center:

http://science.sciencemag.org/content/358/6366/984

The current record holder has 175 transistors and is already considered for actual missions. The article also mentions a separate work done at JPL using mechatronics (gears and stuff) instead of transistors, which sounds positively like steampunk.


Posted by: JRehling Dec 5 2017, 04:12 PM

The topic is a bit timely, with Mars Insight launching soon: a low-bandwidth lander with a conventional camera, conventional laser spectrometer, and conventional mass spectrometer plus high-temperature electronics supporting a seismometer could be a heck of a mission. The first three instruments would work for an hour and give us observations upon arrival, while the seismometer would work for months, at least. I suspect that Venus has enough quakes that a few months would be very informative. It'd be really nice to drop two of these at different latitudes of the same longitude and locate the epicenter of the quakes.

Posted by: Gerald Dec 5 2017, 07:12 PM

In order to investigate possible ongoing volcanism, I'd presume, that one would be interested in longer-lasting atmospheric spectrometry.

Posted by: JRehling Dec 7 2017, 04:48 PM

Long-term monitoring of atmospheric composition would certainly be interesting and perhaps the instrument and its logic could be done with high temperature electronics. It's an open question as to how long an interval would be likely to detect changes, which has been done from orbit, revealing roughly one spike in SO2 per decade. Perhaps smaller spikes are more frequent.

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