NASASpaceFlight.com Forum
Robotic Spacecraft (Astronomy, Planetary, Earth, Solar/Heliophysics) => Space Science Coverage => Topic started by: zubenelgenubi on 11/23/2017 07:53 pm
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In the Science article Armed with tough computer chips, scientists are ready to return to the hell of Venus (http://www.sciencemag.org/news/2017/11/armed-tough-computer-chips-scientists-are-ready-return-hell-venus):
Another test of [NASA Space Flight Center] Glenn's silicon carbide electronics could potentially come quite soon: a proposal called Venus Bridge Orbiter and Surface Science (V-BOSS), one of two candidates for a quick-to-fly, low-cost (less than $200 million) "Venus Bridge" mission that NASA's associate administrator for science, Thomas Zurbuchen, asked Venus scientists to prepare in the wake of the failed Discovery [13/14] round. While details of the V-BOSS won't be set until early next year, it would build off of the LLISSE and add an orbiter to relay lander data back to Earth.
In this presentation at the 12th Low-Cost Planetary Missions Conference, Pasadena, CA, August 15, 2017
Venus Bridge: A Smallsat Program Through the Mid-2020s (http://www.lcpm12.org/wp-content/uploads/2017/08/1215-1235-Grimm.pdf), by Robert Grimm (SwRI), James Cutts (JPL), Martha Gilmore (Wesleyan U.), Robert Herrick (U. Alaska), Gary Hunter (GRC), Noam Izenberg (APL), Kandis Lea Jessup (SwRI), and Robert Lillis (UCB)
VEXAG was directed in Feb 2017 by NASA’s Science Mission Directorate Associate Administrator (T. Zurbuchen) to determine if useful Venus exploration can be performed within a $200M cost cap.
A “Venus Bridge” Focus Group was chartered to consider ideas on architectures, technology, and science that
could be pursued by one or more small missions launching in the early-to-mid 2020s.
The opportunity to study the feasibility of implementing linked missions and demonstrating or developing new technology within the defined cost cap were key aspects of the charter.
And
Perform Two Studies of Linked Orbital and In Situ Elements
Orbiter + surface element (lander): GRC / COMPASS
Orbiter + atmospheric element (probe or aerial platform): JPL / Team X.
The two orbiters will be configured with different strawman instruments.
Element linkage as single package, single launch, or separate launches.
Delivery to Venus most likely from fly-by or separation from other interplanetary injection.
James Cutts is also listed as on the "Venus Exploration Roadmap Topical Analysis Group and Venus Bridge Focus Group" on the VEXAG "About Us" page https://www.lpi.usra.edu/vexag/about-us/ .
Also, there's the VEXAG 2017 Town Hall meeting: https://www.lpi.usra.edu/vexag/meetings/Townhall-LPSC-2017/Presentation.pdf
And, there's the Venus Science & Exploration: Decadal Mid-Term Status, The Venus Exploration Analysis Group (VEXAG) at: http://sites.nationalacademies.org/cs/groups/ssbsite/documents/webpage/ssb_180559.pdf
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What is the other candidate mission mentioned, but not named, in the Science article quote?
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https://youtu.be/BuR5ect-B34
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Between the computer chips and 'steampunk' (for lack of an astute yet flamboyant description of mechanical clockwork computing), it seems reasonable to reattempt a visit to Venus. I think the trick might be to focus on simple missions, at least for anything that lands. Even without the aforementioned developments, orbiting Venus and entering its atmosphere are currently achievable; the DaVinci proposal would have been interesting for one.
While chemistry seems to be the biggest interest, I'd be more interested in the interior of Venus so we can properly see how it compares to Earth; indeed how two Earths can differ in more than atmosphere and location. Between the eschewed (if just nonexistent) plate tectonics, massive lava cataclysm that resurfaced the planet within the last billion years, and missing magnetosphere, those already imply something's not Earthlike inside. That'd be my justification for, at least with landers, attempting seismology first while leaving chemistry and other investigations to orbiters and balloons.
What would be needed to arrange a seismometer package on Venus, assuming either 'hot chips' or 'steampunk' methods in as simple yet useful a device as possible?
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I wonder how the VICI funding from New Frontiers 4 impacts this proposal. Unless NASA gives a formal new start I am afraid that at best this mission will be similar to Resource Prospector: Not enough to die but not enough to live either
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What would be needed to arrange a seismometer package on Venus, assuming either 'hot chips' or 'steampunk' methods in as simple yet useful a device as possible?
SiC chips are quite exotic and not-quite-available yet.
SiC transistors and diodes however are readily available and quite suitable for simple multiplication and simple signal selection, as well as some power amplification.
A simple architecture for a device to last 12h would be something like a dewar with ice in, cooled to -40C (a commonly available industrial minimum temperature), which has (say) 5l internal volume, 4l filled with ice.
The dewar suffers a heat gain of some 50W (guesstimation based on my thermos which does 4W@473K internal), and assuming it's a little better because it's $100k).
4kg of ice melting gives you 1.2MJ, and heating from -40 to +60C gives you another 1.6MJ, 2.8MJ/(3600s*50W)=15h.
Add a sodium-sulfur battery, on the hot-side for power, pop up when you've landed a little disposable camera that takes a superresolution pan and melts once you've got that data safe onboard to stream up.
Once the high res sensor has melted, you get one or ten pixels back over a fibre, and motor drive signals to move the camera head around and do spectroscopy over.
Your room-temperature electronics then broadcast the camera data at a high rate to an orbiter to earth, which can then command the spectrometer to be pointed at things, and arms to extend and grab stuff and ...
Once the room temperature side dies, you fall back on really simple stuff, perhaps with a SiC microcontroller, perhaps not.
Low power oscillator fed a minimally processed signal from seismometer and anemometer, in a multiplexed manner. (only in line of sight, of course)
Even more advanced stuff might be doable by compromising the heat leak into the dewar a little, and using a camera inside, with a relay lens.
Allowing even fairly minimal ICs on the outside of the cold-box (such as those mentioned above), as well as cameras, makes this project a whole lot easier.
In many ways, outside the hot box, this looks more like 1900s electronics than 2020. Eveything is more bulky, there are very limited polymers, and more ceramics and use of spaced insulation rather than plastic seperators.
Bearings are much larger and due to worse magnet performance motors are heavier and produce less power.
Modern small silicon ICs make this quite a lot better than the later Veneras in that they can get a lot of data very fast, and store it for replay to the relay.
(https://i.redditmedia.com/djTbAVyxRJT8X0InjYKfUNFAAxQvbBpeZKUZethKJx8.jpg?w=998&s=a5bc2ef7705e1fa7bdb3bd514dcd6630)
Something more like a 8K*64K panorama with many different filters (at a somewhat lower resolution) in the minute or so the camera takes to overheat.
Another interesting idea may be that as it is so much, much easier to soft-land stuff on Venus, you make a few dozen little kilo packages that are supposed to last only minutes on the surface, and soft-land due solely to the density of the atmosphere.
You toss them out once your dispenser craft slows to mach 1, and then as it further slows, pop out a small basically off-the-shelf RC drone at ~0.5 bar and 55km. Circle round over the balls and collect their data and then relay to orbit and hence to Earth.
This would all be with pretty near-term or current technology - the last requires almost no technology development, and gives you close-up images of a dozen or two widely seperated sites, and images of the descent through the atmosphere.
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Gallium nitride processor: Next-generation technology for space exploration
http://www.spaceflightinsider.com/missions/commercial/gallium-nitride-processor-next-generation-technology-space-exploration/
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What would be needed to arrange a seismometer package on Venus, assuming either 'hot chips' or 'steampunk' methods in as simple yet useful a device as possible?
SiC chips are quite exotic and not-quite-available yet.
SiC transistors and diodes however are readily available and quite suitable for simple multiplication and simple signal selection, as well as some power amplification.
That's a start at least. I wouldn't expect any mission within the next 15 years to employ exotic means yet.
A simple architecture for a device to last 12h would be something like a dewar with ice in, cooled to -40C (a commonly available industrial minimum temperature), which has (say) 5l internal volume, 4l filled with ice.
12 hours would be remarkable enough; poor Philae had to settle for a similar amount of time and managed to accomplish the majority of its objectives before being reduced to intermittent contact and a slow death. Even Huygens operated for barely longer than the Veneras and likewise garnered a healthy amount of data on Titan.
Once the room temperature side dies, you fall back on really simple stuff, perhaps with a SiC microcontroller, perhaps not.
Low power oscillator fed a minimally processed signal from seismometer and anemometer, in a multiplexed manner. (only in line of sight, of course)
Are there any other forms of analog instruments that could operate?
I would presume temperature devices would have some difficulty, mainly because Venus is perpetually hot, but could a thermocouple be optimized to measure a range of say 400 to 500 degrees Celsius? What Wikipedia says regarding nickel,platinum, or iridium-alloyed thermocouples cites ranges as high as 2000 degrees Celsius.
Another interesting idea may be that as it is so much, much easier to soft-land stuff on Venus, you make a few dozen little kilo packages that are supposed to last only minutes on the surface, and soft-land due solely to the density of the atmosphere.
You toss them out once your dispenser craft slows to mach 1, and then as it further slows, pop out a small basically off-the-shelf RC drone at ~0.5 bar and 55km. Circle round over the balls and collect their data and then relay to orbit and hence to Earth.
This would all be with pretty near-term or current technology - the last requires almost no technology development, and gives you close-up images of a dozen or two widely seperated sites, and images of the descent through the atmosphere.
It sounds like something styled after Huygens with a goal of 6 hours for active operation could be reasonable to accomplish. I still would like to know more about what a 'steampunk' device could do at best, including if relaying its data back to an orbiter without active radio is possible; I heard some vague bits about an orbiter sending radar and the passive lander reflecting it back with flickers in the singnal.
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Electronics that can work under Venus conditions seems to be on its way (SiC and GaN).
But how would one power a long duration lander on Venus? There are GaN solar cells. Would they work at Venus temperatures and is there enough light coming in through the athmosphere?
The thick athmosphere might allow wind power. Has this been explored? It's supposed to power the steam punk rower...
According to wikipedia (https://en.wikipedia.org/wiki/Rare-earth_magnet#Magnetic_properties), the curie temperature of some rare earth alloys is well above the venus surface temperature, so electric motors and generators should be possible.
Edit: Found this NASA report from 2013 about solar power for Venus: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150016298.pdf
The surface and lower atmosphere of Venus is a poor place for the use of photovoltaic power systems, because of high temperatures, low light levels, and a spectrum that is deficient in the short-wavelength part of the spectrum. Nevertheless, testing has shown that existing solar cells continue to function without catastrophic degradation at temperatures up to 400°C, equal to that found at the highest elevations of the Venus surface, and calculations show that while the amount of power produced by photovoltaic cells under the expected Venus solar spectrum is low, the power production is not zero. Solar arrays near the equator would produce about 8.7 W/m2 at the average surface of Venus, and 22 W /m2 at elevation of 5 km above the mean surface. We conclude that photovoltaic panels could be used as a power source for missions to the surface of Venus.
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Electronics that can work under Venus conditions seems to be on its way (SiC and GaN).
But how would one power a long duration lander on Venus? There are GaN solar cells. Would they work at Venus temperatures and is there enough light coming in through the athmosphere?
Let's see, a room-temparature dewar flask, a high temperature atmosphere and some high temperature thermocouples... Sounds like power with no moving parts to me.
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Electronics that can work under Venus conditions seems to be on its way (SiC and GaN).
But how would one power a long duration lander on Venus? There are GaN solar cells. Would they work at Venus temperatures and is there enough light coming in through the athmosphere?
Let's see, a room-temparature dewar flask, a high temperature atmosphere and some high temperature thermocouples... Sounds like power with no moving parts to me.
Not really "long duration" unless you figure out how to keep the dewar flask at room temperature.
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Haven't seen this here yet: https://www.lpi.usra.edu/vexag/meetings/archive/vexag_15/presentations/2-Nguyen-HOTTech-Overview.pdf
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Slowly getting somewhere:
https://spectrum.ieee.org/tech-talk/semiconductors/devices/making-radio-chips-for-hell
http://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1270913&dswid=4449
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The Venus Exploration Analysis Group (https://www.lpi.usra.edu/vexag/):
Venus Technology Plan 12/2018 (https://www.lpi.usra.edu/vexag/reports/Venus-Technology-Plan-DRAFT-V1.pdf)
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Another interesting update: Integrated Circuits to Enable Exploration of the Harshest Environments in the Solar System (https://science.nasa.gov/technology/technology-highlights/integrated-circuits-to-enable-exploration-of-the-harshest-environments-in-solar-system)
Although the complexity of these new SiC electronics is presently comparable to that of standard commercial electronics in the 1970s, such electronics at that time nevertheless made possible the Viking and Voyager probes that successfully pioneered historic breakthroughs during their planetary exploration missions.
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NASA Update from Sep 12, 2023: HOTTech Attempts to Tackle Venus (https://science.nasa.gov/technology/technology-highlights/hottech-attempts-to-tackle-venus)
They are making progress with true integrated circuits: A notable “first” achieved in the GEER test was the successful operation of electronic memory, which allows scientific data to be stored until it can be transmitted using silicon carbide (SiC) electronics.