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Future Venus Missions
Phil Stooke
post Jul 1 2005, 01:30 AM
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Oh well, might as well start that new topic since it's already well advanced in the Juno area...

My perspective on landers is as follows. All the landers we've had so far were dropped blind onto an essentially unknown surface. Any future landers can be targeted for specific terrains. It really is not true that we have had representative landings. Even a descent image or two, a panoramic photo plus a bit of surface composition, from a simple Venera-class lander just updated a bit, would be useful if we could put several down at well chosen targets. My choices would be:

Examples of the main plains units (smooth, fractured, ridged)

tesserae

high elevation radar-bright tesserae

large fresh lava flow unit ('fluctus')

crater dark parabola

crater ejecta outflow unit

dunes area.

And I have always assumed, rightly or wrongly, that it would be relatively easy to put these down, so they ought to be fairly inexpensive as planetary landers go.

Phil


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Guest_BruceMoomaw_*
post Jul 1 2005, 09:23 AM
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Well, to repeat a point I've suggested (somewhere) on this site before: given the great additional difficulty of designing a Venus probe if you have to add an airlock to it to allow it ingest samples into its interior, how much good compositional data can you get on Venus' surface WITHOUT such an airlock. A surprising amount, I suspect. A test has already shown that the LIBS system planned for instantaneous, precise and long-distance element measurements on the MSL rover should work just as well in Venus' environment ( ).

On Mars and on airless worlds, this instrument can probably be combined with a Raman spectrometer (which also uses laser light) for a lot of mineralogy studies (although this system wasn't considered quite ripe enough by the LIBS group right now to add it to their proposal for the MSL's LIBS; it's worked fine in ground tests). I'm not sure whether Raman would work as well at long-range in the super-dense Venusian atmosphere -- it relies on measuring an extremely small trace of backscattered laser light -- but even if it doesn't, you could put the fiber-optic connections to a Raman spectrometer and its laser on a simple arm on the lander to contact the local surface in different places. You could also add other gadgets to that arm: a microscopic imager, and maybe even an abrading wheel to grind the weathering crust off Venusian rocks -- which the lander could probably locate on the surface using a simple hardness sensor on the arm.)

Add a panning near-IR spectrometer to the lander (plus a tiltable flashlamp (or broadband laser) to periodically illuminate the surface and allow that spectrometer to distinguish its reflectance spectra from thermal emission spectra), and maybe also a gamma-ray spectrometer inside the lander's hull, and you could answer damn near every important scientific question about Venus' surface -- except for in-situ age dating -- without ANY airlock, and without any need for instruments that require a long time to gather their data (such as X-ray and Mossbauer spectrometers). An X-ray diffractometer like the one on MSL (which also requires ingested samples) could provide additional mineralogy data, but I question whether it's really essential by itself given the Raman and near-IR spectrometers.
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JRehling
post Jul 1 2005, 04:28 PM
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Phil is, of course, completely right about the list of interesting Venus terrains; I think anything but an aerobot approach will leave us a long time in seeing all of them, but a network of four geophysical stations ought to be chosen opportunistically to sample some of the more unusual locations.

A possible Venus exploration gizmo: either an aerobot or a stationary lander that needed a source of artificial light to do spectroscopy despite the incessant IR glow could have microprojectiles that contain nothing but a flash device. This need not require any wet chemistry or electronics whatsoever, or very minimal versions thereof, and therefore be extremely simple and light. An aerobot could drop them, or a stationary lander could eject them several (tens of?) meters away, and then the main craft would image the surface at the time/place of the flash. To get the purest signal, this could be done at night, when only the venusian IR glow would persist. Of course, with-flash and without-flash data would help to get rid of the noise. Perhaps this adds nothing to the LIBS approach -- the question is whether a laser casts its light farther and cheaper and more multispectrally than a "bottlerocket" style of flash. The laser could be used more often, but the flash would allow work at a distance to eliminate all of the scattering problems of the laser and half of the atmospheric absorption. Perhaps an aerobot that is not configured for Venus surface heat, but stays a few km up, could make use of flashes in a circumstance where a laser would require a lower and hotter "perivenus"? Just a thought on the behalf of 13th century technology.
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JRehling
post Dec 15 2005, 01:34 PM
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QUOTE (JRehling @ Jul 1 2005, 08:28 AM)
A possible Venus exploration gizmo: either an aerobot or a stationary lander that needed a source of artificial light to do spectroscopy despite the incessant IR glow [...]
*


A bit of terrestrial exploration of Venus: Christophe Pellier's images of Venus's nightside in the 2004 section overexpose the dayside in IR and you can faintly make out the nightside glowing from the surface heat!

http://www.lpl.arizona.edu/~rhill/alpo/venustuff/recobs.html

This is the first I have seen this in a photograph.

There have always been rumors of people seeing an "ashen light", seeing exactly this sort of spectacle, with the eye. Well, 1000 nm is certainly beyond the abilities of human detection, and I'm highly skeptical that anyone could see this with their own rods and cones.
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Jeff7
post Dec 15 2005, 06:33 PM
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QUOTE (JRehling @ Dec 15 2005, 08:34 AM)
A bit of terrestrial exploration of Venus: Christophe Pellier's images of Venus's nightside in the 2004 section overexpose the dayside in IR and you can faintly make out the nightside glowing from the surface heat!

http://www.lpl.arizona.edu/~rhill/alpo/venustuff/recobs.html

This is the first I have seen this in a photograph.

There have always been rumors of people seeing an "ashen light", seeing exactly this sort of spectacle, with the eye. Well, 1000 nm is certainly beyond the abilities of human detection, and I'm highly skeptical that anyone could see this with their own rods and cones.
*


I suppose it might be possible - a few people can hear much higher frequencies than the average person. It doesn't seem too far fetched that we'd get the occasional genetic abnormality that would alter a person's visual spectrum slightly. But granted, stretching it all the way to 1000nm may be a bit much.
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JRehling
post Dec 15 2005, 09:21 PM
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QUOTE (Jeff7 @ Dec 15 2005, 10:33 AM)
I suppose it might be possible - a few people can hear much higher frequencies than the average person. It doesn't seem too far fetched that we'd get the occasional genetic abnormality that would alter a person's visual spectrum slightly. But granted, stretching it all the way to 1000nm may be a bit much.
*


Well, it's not only how far out 1000nm is, but the fact that normal people have a greatly diminished sensitivity even at red. You can see a red laser in a dark room, sure, but a dim red light is much harder to see a dim green light of the same energy. Rods are only slightly sensitive to red light (they have about the same response curve peak as green-sensitive cones)... and when it comes to detecting *dim* red that happens to be right next to dazzling bright white (!) I am *very* skeptical. If the night side of Venus were somehow isolated from that bright crescent, I might believe it. Put another way, someone orbiting over the night side of Venus would have a much better chance of looking down and seeing non-black than someone on Earth looking into the bright crescent and seeing *dim* dark, near IR.
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Bob Shaw
post Dec 15 2005, 11:38 PM
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A simple explanation for at least part of the story:

If the light reflected off Venus can cast shadows on Earth, then Earthshine must similarly illuminate the night side of Venus (remember the Clementine Lunar night-side shots, with the Solar corona and various planets in view, and think, if you will, how *dark* the surface really is compared to the white clouds covering Venus). Of course, at closest approach Venus is 100x further away than the Moon, so the effect will always be somewhat less...

If the Ashen Light waxes and wanes with Terrestrial cloud cover, then the case is settled (that phenomenon is visible on the Moon, and has been used to estimate changes in the overall albedo of the Earth).

I wonder whether Venus Express will be able to image the clouds of Venus by Earthshine?

Bob Shaw


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Posts in this topic
- Phil Stooke   Future Venus Missions   Jul 1 2005, 01:30 AM
- - BruceMoomaw   Well, to repeat a point I've suggested (somewh...   Jul 1 2005, 09:23 AM
|- - JRehling   Phil is, of course, completely right about the lis...   Jul 1 2005, 04:28 PM
|- - JRehling   QUOTE (JRehling @ Jul 1 2005, 08:28 AM)A poss...   Dec 15 2005, 01:34 PM
|- - Jeff7   QUOTE (JRehling @ Dec 15 2005, 08:34 AM)A bit...   Dec 15 2005, 06:33 PM
|- - JRehling   QUOTE (Jeff7 @ Dec 15 2005, 10:33 AM)I suppos...   Dec 15 2005, 09:21 PM
|- - Bob Shaw   A simple explanation for at least part of the stor...   Dec 15 2005, 11:38 PM
|- - JRehling   QUOTE (Bob Shaw @ Dec 15 2005, 03:38 PM)A sim...   Dec 16 2005, 02:17 AM
- - BruceMoomaw   I see I forgot to provide the URL for the LPSC abs...   Jul 1 2005, 09:27 AM
|- - Myran   QUOTE (BruceMoomaw wrote.)....and without any need...   Jul 1 2005, 04:31 PM
- - BruceMoomaw   The main justification for simplifying a Venus lan...   Jul 1 2005, 11:28 PM
|- - AndyG   Given that the surface is so hot and so highly pre...   Jul 7 2005, 02:39 PM
|- - Bob Shaw   As there are some fairly well-described outline de...   Jul 7 2005, 02:54 PM
|- - JRehling   QUOTE (Bob Shaw @ Jul 7 2005, 07:54 AM)As the...   Jul 7 2005, 08:18 PM
- - BruceMoomaw   Actually, this type of mission -- a balloon using...   Jul 8 2005, 01:58 AM
|- - Bob Shaw   Bruce: Very interesting - you are a fount of know...   Jul 8 2005, 02:47 PM
|- - Bob Shaw   Among the interesting points in the .PDFs to which...   Jul 8 2005, 03:03 PM
||- - Bob Shaw   A conceptual small Venus atmosphere probe picture ...   Jul 20 2005, 01:45 PM
|- - gndonald   QUOTE (Bob Shaw @ Jul 8 2005, 10:47 PM) S...   Feb 20 2006, 04:34 PM
- - remcook   ESA is looking at a mission that is using a balloo...   Jul 20 2005, 01:53 PM
- - BruceMoomaw   NASA's Venus Exploration Analysis Group (VEXAG...   Nov 6 2005, 02:15 AM
|- - JRehling   QUOTE (BruceMoomaw @ Nov 5 2005, 07:15 PM)the...   Nov 6 2005, 06:29 AM
- - remcook   a good update from emily on oncoming missions (VEX...   Nov 9 2005, 10:01 AM
- - BruceMoomaw   To my delight, last night I stumbled by chance acr...   Nov 24 2005, 03:23 PM
|- - JRehling   QUOTE (BruceMoomaw @ Nov 24 2005, 07:23 AM)On...   Nov 25 2005, 05:22 PM
- - BruceMoomaw   One other thing which I just now noticed on the la...   Nov 24 2005, 03:26 PM
- - Phil Stooke   I just tried to access the Venus lander PDS file B...   Nov 24 2005, 04:10 PM
- - BruceMoomaw   It just came through OK for me again (using the UR...   Nov 24 2005, 10:10 PM
|- - vjkane2000   QUOTE (BruceMoomaw @ Nov 24 2005, 03:10 PM)On...   Nov 26 2005, 06:31 AM
- - Phil Stooke   You're right, Bruce... tried a different machi...   Nov 25 2005, 02:22 PM
- - BruceMoomaw   Remember Magellan, which completed 1.5 orbits arou...   Nov 26 2005, 02:27 AM
- - BruceMoomaw   This wouldn't make the SAGE landers that much ...   Nov 26 2005, 08:24 AM
|- - vjkane2000   QUOTE (BruceMoomaw @ Nov 26 2005, 01:24 AM)Th...   Nov 27 2005, 06:08 AM
|- - JRehling   QUOTE (BruceMoomaw @ Nov 26 2005, 12:24 AM)Th...   Nov 27 2005, 07:13 AM
- - edstrick   I'd be really interested in knowing the calcul...   Nov 27 2005, 09:51 AM
- - BruceMoomaw   First: it's not the WEIGHT of imaging cameras ...   Nov 27 2005, 09:55 AM
- - Phil Stooke   Bruce said: "One possibility that comes to m...   Nov 27 2005, 09:32 PM
|- - tedstryk   Another possibility is, if the probe transmits at ...   Nov 28 2005, 03:01 AM
|- - vjkane2000   QUOTE (tedstryk @ Nov 27 2005, 08:01 PM)Anoth...   Nov 28 2005, 03:34 AM
- - BruceMoomaw   But, once again, a high-resolution radar orbiter -...   Nov 28 2005, 02:09 AM
- - Phil Stooke   Bruce, yes, lots of tesserae have small ponds of l...   Nov 28 2005, 03:34 AM
- - edstrick   The frustration of understanding anything about th...   Nov 28 2005, 06:16 AM
- - RNeuhaus   Why does not do design a good space architecture a...   Nov 28 2005, 03:20 PM
|- - JRehling   QUOTE (RNeuhaus @ Nov 28 2005, 07:20 AM)Why d...   Nov 28 2005, 04:51 PM
|- - RNeuhaus   QUOTE (JRehling @ Nov 28 2005, 11:51 AM)An or...   Nov 28 2005, 08:42 PM
- - BruceMoomaw   I take for granted that the first three or four ge...   Nov 29 2005, 01:16 AM
- - djellison   Ahh - Nico and I saw a presentation about that at ...   Dec 15 2005, 01:38 PM
- - BruceMoomaw   Yep. One would think that -- if the Ashen Light a...   Dec 16 2005, 03:17 AM
|- - David   QUOTE (BruceMoomaw @ Dec 16 2005, 03:17 AM)Ye...   Dec 16 2005, 01:48 PM
- - BruceMoomaw   Well, it's a fact that E.E. Barnard -- one of ...   Dec 16 2005, 11:27 PM
|- - Bob Shaw   There's an empirical test (for once), and that...   Dec 17 2005, 12:22 AM
|- - David   QUOTE (BruceMoomaw @ Dec 16 2005, 11:27 PM)We...   Dec 17 2005, 12:47 AM
|- - JRehling   QUOTE (BruceMoomaw @ Dec 16 2005, 03:27 PM)We...   Dec 17 2005, 06:28 AM
|- - ljk4-1   QUOTE (BruceMoomaw @ Dec 16 2005, 06:27 P...   Feb 21 2006, 10:20 PM
|- - Bob Shaw   QUOTE (ljk4-1 @ Feb 21 2006, 10:20 P...   Feb 21 2006, 10:54 PM
||- - DonPMitchell   Bob, what in particular did you want to know about...   May 4 2006, 08:33 PM
||- - Bob Shaw   QUOTE (DonPMitchell @ May 4 2006, 09:33 P...   May 7 2006, 03:51 PM
||- - DonPMitchell   QUOTE (Bob Shaw @ May 7 2006, 08:51 AM) D...   May 7 2006, 05:37 PM
||- - Bob Shaw   Don: Thanks! I hadn't previously realise...   May 7 2006, 06:02 PM
||- - DonPMitchell   QUOTE (Bob Shaw @ May 7 2006, 11:02 AM) D...   May 7 2006, 06:10 PM
||- - Bob Shaw   QUOTE (DonPMitchell @ May 7 2006, 07:10 P...   May 7 2006, 06:14 PM
||- - DonPMitchell   QUOTE (Bob Shaw @ May 7 2006, 11:14 AM) C...   May 7 2006, 07:13 PM
||- - mchan   Over mine, too. IJFGI. Learn something new every...   May 8 2006, 12:52 AM
||- - Bob Shaw   QUOTE (mchan @ May 8 2006, 01:52 AM) Over...   May 8 2006, 09:07 PM
|- - JRehling   QUOTE (ljk4-1 @ Feb 21 2006, 02:20 P...   Feb 21 2006, 11:56 PM
- - dvandorn   One reason Martian craters are hard to see from Ea...   Dec 17 2005, 01:39 AM
- - Phil Stooke   I think the whole issue of earth-based identificat...   Dec 17 2005, 05:21 AM
|- - Bob Shaw   QUOTE (Phil Stooke @ Dec 17 2005, 05:21 A...   Feb 20 2006, 10:11 PM
- - edstrick   There was a full set of preliminary science papers...   Feb 22 2006, 08:37 AM
- - Phil Stooke   Replying to Bob about seeing Aristarchus with his ...   Feb 22 2006, 01:34 PM
- - BruceMoomaw   The presentations from the second VEXAG meeting ha...   May 3 2006, 02:51 PM
|- - nprev   Mr. Esposito's presentation was indeed informa...   May 5 2006, 12:40 AM
|- - DonPMitchell   QUOTE (nprev @ May 4 2006, 05:40 PM) Mr. ...   May 5 2006, 01:53 AM
|- - BruceMoomaw   QUOTE (nprev @ May 5 2006, 12:40 AM) Mr. ...   May 6 2006, 09:22 AM
|- - PhilHorzempa   QUOTE (BruceMoomaw @ May 6 2006, 05:22 AM...   May 7 2006, 04:39 AM
||- - DonPMitchell   QUOTE (PhilHorzempa @ May 6 2006, 09:39 P...   May 8 2006, 09:08 AM
|- - tty   QUOTE (BruceMoomaw @ May 6 2006, 11:22 AM...   May 7 2006, 06:00 PM
|- - BruceMoomaw   QUOTE (tty @ May 7 2006, 06:00 PM) Plate ...   May 8 2006, 01:39 AM
- - RNeuhaus   I feel that the last proposal from VEXAG is more s...   May 3 2006, 04:01 PM
- - Phil Stooke   Hi Don! That was quick! Phil   May 4 2006, 09:00 PM
- - BruceMoomaw   Aha! I always wondered why Madame de Pompadou...   May 8 2006, 10:09 PM
|- - Bob Shaw   QUOTE (BruceMoomaw @ May 8 2006, 11:09 PM...   May 8 2006, 10:40 PM
|- - Chmee   QUOTE (Bob Shaw @ May 8 2006, 06:40 PM) B...   May 9 2006, 04:28 PM
|- - ljk4-1   QUOTE (Chmee @ May 9 2006, 12:28 PM) So w...   May 9 2006, 05:56 PM
|- - Bob Shaw   QUOTE (Chmee @ May 9 2006, 05:28 PM) So w...   May 9 2006, 05:56 PM
- - BruceMoomaw   After clawing my way through my CD-ROM library of ...   May 12 2006, 08:08 AM
- - vjkane   Presentations from the last VEXAG meeting are now ...   Jul 23 2008, 03:48 PM
- - Vultur   I think Venus rovers and balloons, someday, might ...   Nov 15 2008, 07:49 PM
- - Enceladus75   Whilst it would be brilliant to have rovers on Ven...   Nov 19 2008, 07:58 PM
- - PhilCo126   Venus resembles a depiction of "Hell" so...   Nov 20 2008, 07:04 PM
- - Juramike   The Venera landers did manage last about an hour o...   Nov 20 2008, 08:35 PM
|- - vjkane   QUOTE (Juramike @ Nov 20 2008, 08:35 PM) ...   Nov 21 2008, 05:31 PM
|- - huygens_stowaway   QUOTE (vjkane @ Nov 21 2008, 05:31 PM) Th...   Dec 4 2008, 09:37 PM
|- - centsworth_II   QUOTE (huygens_stowaway @ Dec 4 2008, 04...   Dec 4 2008, 10:02 PM
- - Paolo   An interesting Venus Flagship Mission Study   Jul 12 2009, 03:01 PM
- - qraal   Hi Guys Geoff Landis discusses aerobots and surfa...   Jul 16 2009, 09:34 AM
|- - MahFL   The Landis paper is really interesting, I did not ...   Jul 16 2009, 12:35 PM
|- - stevesliva   QUOTE (MahFL @ Jul 16 2009, 08:35 AM) The...   Jul 16 2009, 03:52 PM
- - tasp   And recall, even with an electronic device operati...   Jul 16 2009, 11:25 PM
- - stevesliva   Yeah. One of the reports mentioned that resistors...   Jul 16 2009, 11:39 PM
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