EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Rick Law on June 18, 2017, 02:45:56 am
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With so many experienced and knowledgeable folks here, I love to see your assessment of how modern electronics would make it easier, harder, or no different.
In the 1960's, USSR landed probes on Venus - atmospheric temperature around 450C-500C, surface pressure about 90x ours. Comparing a probe to survive Venus verses to survive Mars, a Mars probe is a cake-walk.
The longest lasting USSR Venus probe lasted just over two hours. If we (humans) are to do it again, how would we do the electronics for a Venus probe today? Can we make it survive the temperature/pressure part of Venus indefinite?
I know that some IC's are available in military specs and they are a lot more robust. But, I am not sure if any IC can function with temperature 450C-500C indefinitely. Some (non military specs) IC's has (regarding soldering) < 270C for 5 seconds. That alone say it is not going to work well for a probe sitting on Venus at >450C. Batteries - is there even one that could work at 450C-500C? Perhaps we are limited to nuclear reactor power.
For the purpose of this conversation, let's limit the probe's function to camera feed, plus surface temperature, wind speed, and atmospheric pressure. We can also assume that the vehicle that got the probe to Venus remains in orbit and can store/relay information. So, as long as the probe can transmit to the orbiter, the probe is considered as working.
I have some thoughts on it, but I am no where nears the knowledge of some of you folks here. So I love to see your assessments of how we may do it today.
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Vacuum tubes. Lots and lots of tubes. Just put the sensors down there and do the processing up where it's safe...
We could probably make something like Nuvistors as reliable as this
http://www.radiomuseum.org/tubes/tube_175hq.html (http://www.radiomuseum.org/tubes/tube_175hq.html)
Or dig up the "thermionic integrated micromodules" they were working on.
http://www.hts-homepage.de/Silizium/Silizium.html (http://www.hts-homepage.de/Silizium/Silizium.html)
But in general I find the "space folks" go for easy things, over and over and over and over. They talk big, but when it comes to real challenges, they're not interested. (Must be the huge, ossified bureaucracies.)
Venus is one, going inside Jupiter is another. I don't trust Jupiter, I want to know what's going on in there.
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There were so many Russian Venus probes! I had no idea. https://en.wikipedia.org/wiki/Venera
One lesson from that: lens caps are even more of a pain on Venus than on Earth.
It would be nice to start by learning how the Russians did it back then. Does anyone know?
My first thought was evaporative cooling. But wait, the pressure is up to 100 atm. What could you use as coolant?
Isotope decay heat batteries would be hard, since for adequate heat gradient the thermopiles would have to operate at near red heat.
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It would be nice to start by learning how the Russians did it back then. Does anyone know?
http://mentallandscape.com/V_Venus.htm (http://mentallandscape.com/V_Venus.htm)
TL;DR: Heat accumulators (melting lithium nitrate), insulation and lander pre-cooling before separation.
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Tubes don't help any; you definitely don't get much processing power for a given flight platform.
Remember, this thing needs to be shoved up from the surface of Earth! Weight and size is important!
There was an article recently about SiC being tested under similar conditions:
https://www.compoundsemiconductor.net/article/101024-nasa-demos-sic-circuits-for-venus-missions.html (https://www.compoundsemiconductor.net/article/101024-nasa-demos-sic-circuits-for-venus-missions.html)
That's probably not good enough on its own (plus, there's a lot more stuff that needs to be made in SiC, besides just the drivers, microcontroller and link radio -- sensors and cameras and detectors oh my). A refrigerator would be effective at that point, at least: you could get away with silicon (just barely, with no margin) at 200C, say, and that would help a lot with other devices and materials.
Related: http://www.sciencedirect.com/science/article/pii/S0094576507001208?via%3Dihub (http://www.sciencedirect.com/science/article/pii/S0094576507001208?via%3Dihub)
But no, a rover is short sighted -- I think the better plan is a flying machine! The atmosphere is very dense, so it's no trouble at all to fly at a modest altitude, with very little power, or hover with a little helium. This would give us a fantastic opportunity to observe weather patterns (say, equip it with a Doppler radar?) as well as the chemistry at various levels (maybe a mass spec, as well as various THz to UV spectrometers). Radar would of course double for measuring altitude and mapping landforms.
There are so many things to study that you might not think of, right away. What about the electrical environment? Ionosphere? Ion detectors, an electrometer, maybe a wideband radio system to check atmospheric absorption, scattering and other things, that would be cool.
This would be best paired with an orbiter, which can take high resolution radar itself, and has companion instruments for the flier's radio experiments. Could be some bonus knock-on experiments, like attempting to communicate with the Mars orbiter, and occultation with the Sun and planets to better measure orbits, sizes and so on.
Tim
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I know that some IC's are available in military specs and they are a lot more robust. But, I am not sure if any IC can function with temperature 450C-500C indefinitely. Some (non military specs) IC's has (regarding soldering) < 270C for 5 seconds. That alone say it is not going to work well for a probe sitting on Venus at >450C. Batteries - is there even one that could work at 450C-500C? Perhaps we are limited to nuclear reactor power.
Silicon semiconductors have a max temp of about 270degC because it wil just turn conductive above that with little modulation capability. I have no exact knowledge how this was calculated, but relates to the increase of spontaneously generated charge carriers, setting the max temperature at this level in silicon. Maybe it is possible to find a material that goes significantly above this, but finding and developing one is unlikely to be an easy task. Just remember that before the transistor really took off we had to work with a lot of relatively unreliable (Germanium) transistors. It took quite some investment to get this far, and I doubt there will be much market for 400+degC electronic components. I think most probes just relied on thermal insulation for the gear to remain working until it heated as far as to fail.
I heard of molten salt batteries (https://en.wikipedia.org/wiki/Molten-salt_battery), that (only) work on elevated temperatures and might be usable, but I know little of them. I think the electronics might still be an issue.For the purpose of this conversation, let's limit the probe's function to camera feed, plus surface temperature, wind speed, and atmospheric pressure. We can also assume that the vehicle that got the probe to Venus remains in orbit and can store/relay information. So, as long as the probe can transmit to the orbiter, the probe is considered as working.
I have some thoughts on it, but I am no where nears the knowledge of some of you folks here. So I love to see your assessments of how we may do it today.
I think it will be ludacrisly expensive to make this work, but it might be possible. I think the cost would be at least an order of magnitude greater than what humanity is willing to spend on getting a probe to a planet we have very little chance of ever being able to survive. We can scatter the surface with working probes, but what do we realy want to know?
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I will guess that like teslacoil a floating platform would be better, a simple heated bag ( finally a use for weapons grade Plutonium, just take a 5kg unit there in a few long tubes and a driver to modulate the heat slightly) and let it float at around the 1 atmosphere mark, where the atmosphere is mostly CO2. Initial gas fill for descent can be simple cryogenic nitrogen in a dewar, kept cool on the journey there by the simple method of having a heat shield parasol to keep it frozen solid then warm up just before separation and aerobraking, and use half as coolant during this for the instrument package, and boil the rest during parachute descent to inflate the balloon with hot light gas at ambient pressure, then light up the heaters to keep it pressurised. Small reserve of cryogenic gas and then you simply start using ambient CO2 as fill gas.
At 1 atmosphere or so you are going to be within the ability of regular electronics, and above the clouds enough so the major storm action is far below, but you are close enough to use laser to get composition of the lower areas, and sample the ambient, plus use simpler stuff for the probe to get info of the high altitudes, which will be a lot more than a probe in orbit, as you can get a reference for the orbiter instruments to use.
Landers you are really only able to use big phase change thermal sinks, and cool them down during cruise to 3K for best performance, and insulate the heavy steel pressure vessel inside, with a nice polished inner vacuum dewar to hold the electronics and batteries. You probably will want to have 3 different batteries, something low temperature for the start, something medium temp and then an outer sodium sulphur battery for final phase which is activated by being at 400C, acting as both cooler and battery for the high power phase. Then cryofreeze the inner phase change material and design it for a 15 hour life, and it might actually get to that before something fails.
Final thing, use a lens cap that will absolutely, positively, and reliably separate and not foul up the camera or any other science instruments even in failure. You want your probe to last power wise so it's last messages are just data of the main controller and radio transmitter solder joints melting.
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There were so many Russian Venus probes! I had no idea. https://en.wikipedia.org/wiki/Venera
Nor me, I have vague memories of them sending some up but that looks like a truly heroic effort to get images back... even colour corrected ones! Have you seen the weight of some of those probes?! :o
I can't see a great deal of point in a 'do-over' (I understand the fundamental question though). It looks to me as if the Soviets did an outstanding job in establising that the surface looks a bit like a very badly maintained car park! That's very valuable information in itself - it's not a dusty surface, it's hard and rocky and all that implies for sampling.
The most successful approach in their later probes seems to have been to enclose the electronics and everything else in a strong sphere, best for resisting the pressure and smallest surface area, that makes sense. To get any further surface information would require sampling of the rock and some sort of on-board analysis laboratory - that would have to be outside the sphere, and given the temperature and pressure, more or less impossible. Maybe you could do something optical with laser ablation and a spectroscope from inside the sphere but that's about it, as far as I can see.
From the above link I see that the Russians are far from abandoning the programme with another probe due to launch in 2024. The main purpose seems to be radar mapping which seems to be the best approach given the precision that they can monitor changes in height of features on Earth these days.
The main reason for doing anything more on the surface would probably be to investigate mineral exploitation possibilities (I suspect organic life is out). For that, the best bet would be a 'smash and grab' type approach - drop to the surface, grab a rock and get off again (maybe including the Helium baloon method to get to the upper atmosphere before using thrusters) and return it to Earth for analysis. That could still be done with the cool down, insulate and time limit approach that they used.
As far as something staying on the surface 'indefinitely' (for actual mineral exploitation) I think it would have to be much bigger than can be achieved in a single launchable probe - maybe something assembled in orbit. Then you might have the possibility of soft landing something big enough to have an active cooling system - what about some form of heat pump technology that pumps internal heat into a radiator panel that gets hot enough (incandescent) to be able to radiate heat to the surroundings. That would need quite a bit of power too!
I can't see a probe being able to operate internally at surface temperature using current technology, power source, passive and active electronics or other bits - I think it would need to include active cooling.
EDIT: Phew!, hopefully a slightly more insightful reply for my 2000th post than my 'UK mains plug plastic cover' one, that was a near thing!. :phew:
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Apparently NASA has already been working on a new high-temp silicon formula https://phys.org/news/2017-02-nasa-electronics-longer-venus-surface.html
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If we ever wanted to do anything with Venus, perhaps it might be *slightly* more feasible to just remove most of the atmosphere.
No, can't suggest a workable method. But neither can I think of any way to build useful machinery that would run on the surface as it is now.
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As far as something staying on the surface 'indefinitely' (for actual mineral exploitation) I think it would have to be much bigger than can be achieved in a single launchable probe - maybe something assembled in orbit. Then you might have the possibility of soft landing something big enough to have an active cooling system - what about some form of heat pump technology that pumps internal heat into a radiator panel that gets hot enough (incandescent) to be able to radiate heat to the surroundings. That would need quite a bit of power too!
Can you imagine the facility required to test such a machine? !!!! (https://www.eevblog.com/forum/Smileys/default/scared.gif)
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Does anyone have any idea what they want to discover on Venus? Don't get me wrong, it is always fun to think about ways to do the (near) impossible, but no info on what we want the probe, that we want to build at great expense to function reliably for the long term, ever to DO on the surface of Venus. Again, I love thinking about it, but I cannot help seeing actual problems in my own (Dutch) society that might need addressing first. Yeah, mining operations sound tempting, but aside from the logistics, we might want to invest on our own planet just to use a little bit less of the resources we have in a surprising abundance right here.
PS Sorry I am being kind of a whine here, I don't intend to discourage dreaming.
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Again, I love thinking about it, but I cannot help seeing actual problems in my own (Dutch) society that might need addressing first.
1. A Dutchman can't see the relevance of looking at a planet that is literally 100% clouds?! :-DD
2. Besides the applications to weather research, the idea of a flying (not orbiting or hovering or landing) probe is novel, untested (in space -- mind that solar powered airplanes have been tested on Earth for many years, however!), and sure to yield knock-on technological benefits.
3. To be fair, you'll never solve your problems. Not if you concentrate on them, not if you simply funded their solutions / treatments better. We'll never solve our problems. Neither will anyone else. (Not sure if this comes through right; I mean the "you're a jerk, I'm a jerk, that guy over there is a jerk" mode of sarcasm. :P ) Heck, attacking those sorts of (social and political) problems head-on would probably have the opposite effect of bringing unwanted attention to an already unseemly part of existence!
It's like airplane crashes: the less common they are, the more widely reported they are. The fact that they're rare is insanely fantastic (air travel has never been safer). But it also makes them more sensational, and therefore over represented in media. Which gives people the false impression that they're more common than they are. Brains are notoriously bad at stuff like this.
Instead, why not harness our fallacious psychology for good? Why not distract us from our woes with a greater goal, something we can unite behind? It can still be selfish, like pulling down asteroids for precious metals, or it can be lofty and idyllic like starting colonies on other planets and moons!
At least, that's what I like to think about. YMMV. :popcorn:
Tim
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Europa is the right destination. Why not go land somewhere that could return an epic result rather than somewhere we've already been, and we know is a terrible place? It's like staying at a Howard Johnsons more than once. Wasn't the first time bad enough?
Venus, Part Deux would certainly be an interesting engineering exercise, but little more.
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Because we were told, in no uncertain circumstances, to not attempt any landings on Europa.
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Because we were told, in no uncertain circumstances, to not attempt any landings on Europa.
Rules were meant to be broken, even Art Clarke's. :-+
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1. A Dutchman can't see the relevance of looking at a planet that is literally 100% clouds?! [...]
Touché! :-DD
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First, thanks for the many insightful ideas here. I was particularly pleased to find a link to the high-temperature silicon research that NASA is working on. I read a lot but I was totally uninformed about that even existed.
I did not share my thought within the original post because I wanted to hear your thoughts first.
My thoughts are along the line of active cooling of the probe because I believe if we can work out a way to cool the small volume inside a probe, beside making further Venus research easier, many other things can be done with that technology. There is every reason to believe that "air condition" to be workable at 450C. But of course that is a huge engineering challenge.
Flying probes (which is what we used for Jupiter) is an interesting idea and offer many advantages. What it can't do is actual sampling, and one can argue it actually is not ON Venus.
I love the idea of some day human's foot print on Venus. Some proposed mining, but I cannot see a condition that would make Venus raw material back worth the cost of bring it back to earth commercially.
Same reason I dabble in electronics, I like to learn the possible. Hence, the idea of human's foot print on Venus interests me. Mars first... Perhaps even Europa before Venus - wow, the though of what may be swimming below the Europa ice cover just blows my mind.
Thanks for the many mind tingling thoughts presented.
Again, I love thinking about it, but I cannot help seeing actual problems in my own (Dutch) society that might need addressing first.
1. A Dutchman can't see the relevance of looking at a planet that is literally 100% clouds?! :-DD
2. Besides the applications to weather research, the idea of a flying (not orbiting or hovering or landing) probe is novel, untested (in space -- mind that solar powered airplanes have been tested on Earth for many years, however!), and sure to yield knock-on technological benefits.
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Tim
I have rather similar thought, except the Dutchman part. I think it is global and certainly not particular to any individual or to Dutch: Far too many on earth doesn't see the need for space research but think we should spend big bucks on global warming.
Either way, earth as we know it will end: global warming, next ice age, sun going red-giant, asteroid strike, gamma ray burst... Us human will need to find ways around many of those events for us human to stay around just a bit longer till the next crisis.
I think Venus offers excellent opportunity for research. I am not sure I am comfortable with the idea of using a whole planet as a lab, but the idea is an attractive one to me. Seeding the atmosphere with something to reflect more light, actually trying to create a nuclear winter... All are very interesting.
Yeah, hunger and disease on earth is a problem. But if we just focus on that, we may well be left with neither the knowledge or resource to deal with say a discovery of an asteroid that will wipe us out in 9 months.
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Even if Venus research is totally without value, effort expended in this direction has value. There are lots of applications for electronics which can survive high temperatures. Engine controls and monitors. Volcano research gear. Deep oil well loggers. Sensors and controls for really high speed aircraft. Study of the "hot smoker" undersea springs. And many, many more.
Of course this is a two way street. Those other applications may be the source of technologies that enable study of the Venusian surface.
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I love the idea of some day human's foot print on Venus. Some proposed mining, but I cannot see a condition that would make Venus raw material back worth the cost of bring it back to earth commercially.
You're going to have a hell of a job leaving a footprint on that surface! If you can't achieve an actual imprint then you might have to settle for a blob of Hydrocarbon residue. :D
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Developing new technologies under the umbrella of a massively expensive system integration project such as a planetary landing craft is about the most inefficient way to go about it. I know that's a common rationale for executing a space exploration program, but it's just not the best way to develop new science and technologies - if those are the true objective.
We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
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If I recall correctly, the part that failed first on the venera probes was the antennae. The Russians were apparently unable to find a substance with which to coat the antenna array that was both transparent to RF radiation, and immune to an acid bath at huge temperatures and pressures. So they just built massive antennae, knowing that they would die but would hopefully live long enough to get some pictures back.
We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
Mmmm, not sure that I agree with that. There are some very convincing arguments that the real value of the Apollo missions was the huge shot in the arm it gave technological development. Yes, exploration is important. But if we want to remain a world leader in technology, we have to come up with new technology; and space flight is the crucible in which that technology is developed.
If we ever wanted to do anything with Venus, perhaps it might be *slightly* more feasible to just remove most of the atmosphere.
Yep. If we want to make Venus a shade more habitable, we should focus our attention on blowing a megaton of the atmosphere into space.
And if Larry Niven's teleportation booths were ever actually invented, we could teleport that atmosphere to Mars, which could use some extra CO2.
>Charlie
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We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
Mmmm, not sure that I agree with that. There are some very convincing arguments that the real value of the Apollo missions was the huge shot in the arm it gave technological development. Yes, exploration is important. But if we want to remain a world leader in technology, we have to come up with new technology; and space flight is the crucible in which that technology is developed.
Propaganda is often convincing, particularly when is supports our biases.
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I love the idea of some day human's foot print on Venus. Some proposed mining, but I cannot see a condition that would make Venus raw material back worth the cost of bring it back to earth commercially.
You're going to have a hell of a job leaving a footprint on that surface! If you can't achieve an actual imprint then you might have to settle for a blob of Hydrocarbon residue. :D
Naw... hydrocarbon will in time degrade. Let's go for more lasting impressions. Active volcanoes are on Venus and some of the good folks in Pompeii shown us proven ways to leave lasting impressions...
Developing new technologies under the umbrella of a massively expensive system integration project such as a planetary landing craft is about the most inefficient way to go about it. I know that's a common rationale for executing a space exploration program, but it's just not the best way to develop new science and technologies - if those are the true objective.
We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
re: "Developing new technologies under the umbrella of a massively expensive..."
That may be so but doesn't have to be so. That said, we do need massive improvement to how government projects do things. The F35 project is a case and point - an expensive flying turkey.
Massive projects do have another benefit. "Reach the moon this decade..." speech by John F Kennedy (1961) and the one-upmanship during the space race possibly inspired millions world wide to go into science.
One could argue that had there not been a space race and that USSR "lost" (USA getting to the moon first), USSR might not have focus on Venus and did the many "firsts" with their probes to Venus. Much of what we know of Venus came from the many Soviet probes, so we owe our knowledge of Venus to that USSR "defeat".
I think there should be a new 4-way race (US, Europe, Russia, China) for the first working space elevator. Much as I like "foot print on Venus", I prefer the benefit of having a working space elevator first.
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We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
Mmmm, not sure that I agree with that. There are some very convincing arguments that the real value of the Apollo missions was the huge shot in the arm it gave technological development. Yes, exploration is important. But if we want to remain a world leader in technology, we have to come up with new technology; and space flight is the crucible in which that technology is developed.
Propaganda is often convincing, particularly when is supports our biases.
Which part do you think it is mere propaganda?
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We should visit new worlds because they are worth exploring, not because it would be nice to have a new semiconductor at our disposal.
Mmmm, not sure that I agree with that. There are some very convincing arguments that the real value of the Apollo missions was the huge shot in the arm it gave technological development. Yes, exploration is important. But if we want to remain a world leader in technology, we have to come up with new technology; and space flight is the crucible in which that technology is developed.
Propaganda is often convincing, particularly when is supports our biases.
Which part do you think it is mere propaganda?
It has been a longstanding piece of American yore that we went to the moon to get a plethora wondrous space age technology that changed our lives forever more. However, this is what NASA seems to be able to directly attribute to Apollo as technology spinoffs to benefit the common man: https://www.nasa.gov/sites/default/files/80660main_ApolloFS.pdf (https://www.nasa.gov/sites/default/files/80660main_ApolloFS.pdf)
To say that many of the above only would have reached the masses through the benevolent hand of Apollo is to stretch credibility to say the least.
We went the moon to go to the moon. If we went to the moon to get the DustBuster, I would like a refund on both counts, because DustBusters were shit.
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It has been a longstanding piece of American yore that we went to the moon to get a plethora wondrous space age technology that changed our lives forever more. However, this is what NASA seems to be able to directly attribute to Apollo as technology spinoffs to benefit the common man: https://www.nasa.gov/sites/default/files/80660main_ApolloFS.pdf (https://www.nasa.gov/sites/default/files/80660main_ApolloFS.pdf)
To say that many of the above only would have reached the masses through the benevolent hand of Apollo is to stretch credibility to say the least.
We went the moon to go to the moon. If we went to the moon to get the DustBuster, I would like a refund on both counts, because DustBusters were shit.
Ah... I see where we mis-connected. We=(me, you, and CharlieWorton whom you quoted). I can't speak for Charlie, but for me, here is where I think we missed connection:
Spinoff would be a very small subset. SpinOff is a new business entity resulted from the knowledge/technology. Some technologies were developed/refined under contract from NASA done by an existing company. So formation of a new company is not necessary a default condition for new technology.
Teflon for example, invented since 1938, might have stayed in obscurity and never refined. Since it was developed by an existing company (Dupont), no new company (spinoff) was created even while it was a big hit in the market when it went into the consumer world. What we do know is that most of the pots and pans you get even at Walmart today are coated rather than bare-metal. Teflon was the only coating in cookware that I am aware of until recent when newer technology Ceramic coating makes a return. ("Only" as refer to the stuff available in typical stores. I am sure there might have been specialty stores that might have offer something odd. May be coating such as ancient Roman lead-coated cups and cookware.)
I have to agree about the DustBuster - I don't like them. I'd rather the dirt be kept in a bag and throw out the bag when full. Cleaning out the re-usable bag is suppose to be done out doors but people buy the darn thing for convenience. So, at least from personal experience, the bag will be cleaned in door which results in much of the dirt just re-released.
Also, don't forget the energizing effect of a big technology push. Would there have been satellites today had there not been the V2 rocket? Perhaps. But it would be difficult to argue that rocket technology would have advanced at the same pace had WW II not occur. If you talk to people who ended up in science from that generation (high school/early college age during the space race), I bet you would find many who went into science because of the interested the space race kicked up.
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Sure, it is inefficient to count on efforts to reach some specific goal to develop technology for some other purpose. But if the popularity of that thing allows the technology to be developed, great.
The space race has been a great example of selective telling of the truth by two sides. NASA and others want you to believe everything in the modern world came as the result of their efforts. Others say that NASA slowed everything down and we would have many more shiny toys if we hadn't wasted time, talent and money planting flags on the moon.
The truth is somewhere in between. Not all of the money spent on the moon would have been spent productively here on Earth in the absence of the moon program. And the space program did develop many useful things, some of which would probably have not been developed otherwise.