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Future Venus Missions
Juramike
post Nov 20 2008, 08:35 PM
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The Venera landers did manage last about an hour on the surface.

I like to think that with all the improvements in instrumentation technology (and better luck), that a next generation lander could do great science even with only an hour of lifetime.

-Mike


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vjkane
post Nov 21 2008, 05:31 PM
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QUOTE (Juramike @ Nov 20 2008, 08:35 PM) *
The Venera landers did manage last about an hour on the surface. I like to think that with all the improvements in instrumentation technology (and better luck), that a next generation lander could do great science even with only an hour of lifetime.

The current lander plans seem to be counting on about an hour or two, so not much improvement there. However, there are a couple of ways of getting more science. First, you could grab samples, inflate a balloon, and do the analysis in the cool clouds. That is the official Venus lander goal for the New Frontiers Venus mission and I believe for the proposed Venus Flagship mission. However, it's recognized that that approach is expensive, so simply short lived landers are an acceptable alternative and were proposed for the first New Frontiers competition and are rumored to be proposed for the upcoming competition.

The other possibility is to use remote laser sensing (both a la MSL and Raman) to target multiple features at the landing site without the difficult problems of bringing samples inside the craft. My hope is that a periscope could sit atop the lander. An on board camera would analyze images of the site, identify a variety of targets, and target the laser accordingly.

I just posted a long discussion of possible New Frontiers Venus missions at http://futureplanets.blogspot.com/ that discusses these options and has links to proposed mission descriptions.


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huygens_stowaway
post Dec 4 2008, 09:37 PM
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QUOTE (vjkane @ Nov 21 2008, 05:31 PM) *
The current lander plans seem to be counting on about an hour or two, so not much improvement there. However, there are a couple of ways of getting more science. First, you could grab samples, inflate a balloon, and do the analysis in the cool clouds.


I'm definitely no expert on the surface composition of Venus, but I wonder if samples would undergo chemical changes when transported to a much cooler, lower pressure environment prior to analysis. Would any valuable science be lost this way?
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centsworth_II
post Dec 4 2008, 10:02 PM
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QUOTE (huygens_stowaway @ Dec 4 2008, 04:37 PM) *
...I wonder if samples would undergo chemical changes when transported to a much cooler, lower pressure environment prior to analysis....

I expect the collection system would seal samples off from the external environment. The samples would probably be very small.
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Paolo
post Jul 12 2009, 03:01 PM
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An interesting Venus Flagship Mission Study


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qraal
post Jul 16 2009, 09:34 AM
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Hi Guys

Geoff Landis discusses aerobots and surface rovers in some detail. New Silicon carbide electronics can operate at 500 C for hundreds of hours, so they'd be ideal for the rover...

Landis Paper for NASA

VEXAG presentation from 2008

...such a mission would stretch the state-of-the-art, which is a worthwhile goal for NASA. Would also allow design of deep-probes for the gas-giants! Down to the 200 bar level on Jupiter, 300 on Saturn and 800 bar on Uranus/Neptune.
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MahFL
post Jul 16 2009, 12:35 PM
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The Landis paper is really interesting, I did not realise electronics could operate reliably at 500 C.
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stevesliva
post Jul 16 2009, 03:52 PM
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QUOTE (MahFL @ Jul 16 2009, 08:35 AM) *
The Landis paper is really interesting, I did not realise electronics could operate reliably at 500 C.


I don't think they can, yet. I think automotive applications are pushing silicon CMOS electronics to over 200C, and coupled with the reliability requirements of cars, they might start using SiC when it gets to the VLSI stage. Reading the paper, they fully admit that SiC has been played with at 500C, but only on the order of a single logical gate. Their comment, not mine, is that this is comparable with the state of the art during the Mercury program. Between now and when it's used on a spacecraft, someone needs to progress the technology from 10 transistors to a few thousand for a microcontroller. And validate both volatile and nonvolatile memories of some sort. If they get a flip-flop working at 500C, they're golden. The nonvolatile memory can be magnetic coils, Apollo-style. wink.gif

...as I keep reading... Yup, they say memory is still a big unknown in SiC. Oh, and they say it's not yet complementary, so it's higher power than CMOS (where the C stands for complementary).

They also waffle back an forth about what would be heavier:
Electronics running at 300C and a big cooling system.
Or Electronics running at 500C and a smaller cooling system.

Personally, I'd bet that any mission in the next few decades doesn't have any large ICs running at 500C. I'd love to be wrong, though. Maybe private industry will find some application that needs it. Geothermal power or efficient furnaces or something.
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tasp
post Jul 16 2009, 11:25 PM
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And recall, even with an electronic device operating at 500C, you still need insulators, conductors, capacitors, resistors, tuned circuits, etc. And to be able to resist a corrosive environment and high pressure.

This is quite a challenge from a materials engineering standpoint.


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stevesliva
post Jul 16 2009, 11:39 PM
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Yeah. One of the reports mentioned that resistors exist that work at 500C, but existing capacitors don't, really.
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tasp
post Jul 17 2009, 03:00 AM
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I think you need a capacitor to make a radio. And just making a high temp cap would not be sufficient, the device would need to maintain precise electrical characteristics over an extreme temperature range. All the parts would be subject to thermal noise effects, particularly amplifiers and digital circuits, and this might be another big problem.

Seems like the mining and drilling industry might have need of devices that would work in this regime. Maybe smelters too. Might be some incentive here to generate some useful spin off devices.


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siravan
post Jul 17 2009, 03:16 AM
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QUOTE (tasp @ Jul 16 2009, 11:00 PM) *
...the device would need to maintain precise electrical characteristics over an extreme temperature range.


Not exactly, temperature on the surface of Venus has a rather narrow range. In fact, the temperature difference between day and night sides is small. You need an electronic system which works in 450-500 C. It does not need to work in lower temperatures. Presumably, the cruise stage and the EDL stage can use separate, "traditional", microelectronic systems.
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Paolo
post Jul 17 2009, 05:46 AM
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Conference on Venera-D (sorry, link in Russian only)
http://www.laspace.ru/rus/news.php#302


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James Van Allen
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stevesliva
post Jul 17 2009, 03:37 PM
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QUOTE (tasp @ Jul 16 2009, 11:00 PM) *
I think you need a capacitor to make a radio. And just making a high temp cap would not be sufficient, the device would need to maintain precise electrical characteristics over an extreme temperature range. All the parts would be subject to thermal noise effects, particularly amplifiers and digital circuits, and this might be another big problem.

Seems like the mining and drilling industry might have need of devices that would work in this regime. Maybe smelters too. Might be some incentive here to generate some useful spin off devices.


I know. You and I are viewing this pretty similarly-- there's a whole 70 years of progress in electronics, discrete, IC, passives, packaging, boards, etc etc that needs to be reinvented for operation above 300C, which is a spec likely driven by automotive applications. Major skepticism. I think the only solution you could rely on in the near term is to throw it over to the mechanical and thermal engineers to make a colder box. The irony is that that's my take as knowing the EE side of things. I'm sure the mechanical engineers don't exactly find it easy, either... but at least there is more precedent for mechanical engineering in extreme environments.
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stevesliva
post Oct 1 2009, 04:45 AM
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QUOTE (stevesliva @ Jul 16 2009, 10:52 AM) *
I don't think they can, yet. I think automotive applications are pushing silicon CMOS electronics to over 200C, and coupled with the reliability requirements of cars, they might start using SiC when it gets to the VLSI stage.

Just saw this article about SiC ICs being pushed to maturity by the hybrid and electric vehicle markets.
http://www.semiconductor.net/article/35522...Time_Coming.php
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