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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, 11:28 PM
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The main justification for simplifying a Venus lander is that it can enable you to launch more than one at one time. Larry Esposito's "SAGE" concept -- which, from what little I know about it, apparently DID have both an airlock and a GCMS atmospheric analyzer -- neverthless consisted of two or three landers on one mission.
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AndyG
post Jul 7 2005, 02:39 PM
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Given that the surface is so hot and so highly pressured, why not take a leaf from the early explorers of the ocean bottoms? Dredge for rocks!

Picture a balloon flying in Venusian atmosphere at about the 32km level. This height is good since it's below the bulk of the cloud cover, giving you the ability to view the surface. Pressure is around 8bar and the temperature is around 200C. Not really a problem for well-designed electronics & balloon materials. Water doesn't automatically boil at this pressure/temp, so may be useful for radiators.

A thin titanium wire, with a basic end effector, could be winched down from a balloon at this height to pick up suitable rocks for analysis back within the balloon. A wire some 1.32 mm across, tapering to around 1mm at the bottom, would in total mass about 160kg, and enable a load of about 20kg to be lifted, assuming some 5kg mass for a grabber/hardened camera, etc.

100kg of lift in a CO2 atmosphere could be provided with just under 8 cubic metres of H2 in the balloon, so the size of the bag could be really quite trivial.

Andy G
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Bob Shaw
post Jul 7 2005, 02:54 PM
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As there are some fairly well-described outline designs for RTG-powered refrigerated landers, I find myself wondering whether the waste heat from the refrigeration system could be used to produce lift in a hot-air balloon. An almost mechanically inert (in terms of externals - obviously, there's pumps and whatnots beavering away inside!) lander could drift around the landscape, rising from time to time then falling once more. Think of a Galilean Thermomoter, and the way the glass spheres bob up and down...

You'd get:

Multiple ground-truth sites
Aerial imaging
Meteorology

And probably a few other goodies, too!


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JRehling
post Jul 7 2005, 08:18 PM
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QUOTE (Bob Shaw @ Jul 7 2005, 07:54 AM)
As there are some fairly well-described outline designs for RTG-powered refrigerated landers, I find myself wondering whether the waste heat from the refrigeration system could be used to produce lift in a hot-air balloon.  An almost mechanically inert (in terms of externals - obviously, there's pumps and whatnots beavering away inside!) lander could drift around the landscape, rising from time to time then falling once more.  Think of a Galilean Thermomoter, and the way the glass spheres bob up and down...

You'd get:

Multiple ground-truth sites
Aerial imaging
Meteorology

And probably a few other goodies, too!
*


It'd be great if it worked, but of course, the refrigeration scheme itself involves a lot of mass per payload mass.

Venus permits a lot of buoyancy, potentially, especially if helium filled the balloon, but that margin could be eaten up with a nuclear-powered refrigerator + thermal insulation + ???

Also, heated CO2 would not give you much buoyancy compared to helium unless you really heated the hell out of it. Venus's high ambient temperature really works against that. To halve the density of CO2, you'd have to double the temperature, up to roughly 1000K! I'm no material scientist, but I guess you're talking about fewer and fewer possible balloon materials that will hold up as a strong, thin film when boosted to white heat!

I think compressing and uncompressing helium (at thermal equilibrium with the outside) would provide a *lot* more lift with less mass. Although, I understand and admire you're looking for synergy between a design side-effect and a possible desirable feature.

The synergy you get in design with Venus balloons is that the higher a balloon resides, the cooler the ambient temperature that must be withstood. If thermal inertia (passive!) can keep the system alive throughout a single exploratory drop, then we might have systems that can only tolerate the Venusian surface environment temporarily, but long enough for an arbitrary number of descents. The Veneras operated in this fashion. A balloon carrying a heat sink could reach thermal equilibrium at 40-100 C. Then the question is: How much time would be required in a surface stay to do useful science? For imagery, very little. To grab a sample, very little. It is possible, in times of favorable geometry, to work a single telemetry/command feedback loop with Earth-based controllers in just a few minutes. (Transmit an image, ask which rock/soil unit should be grabbed, and receive that command -- the AI for that is beyond MER, but not beyond reason.) If a ~45-minute surface stay is well within safe margins for thermal constraints, then that's not a bad MO. If descents could be managed at roughly the rate of one per day, then a lot of surface exploration could take place in a primary mission of two or three weeks.

The whole scheme then could be to identify a swath across one line of latitude of Venus that contains several worthwhile terrain units that are, moreover, going to be in local daylight with a line-of-sight to Earth during a desired primary mission. The craft would control its horizontal motion by ascending into local winds, thereby deriving the horizontal motion. The heat sink would get well below top operating temperature, and then the craft would perform a dive to its target. It would take descent images and a single surface panorama, beam them to Earth, and autonomously perform surface science while awaiting a command from Earth identifying which surface patch to sample by arm. After about 20 minutes, the human-made decision would reach the craft, an arm would make a grab for the target, and then the craft would ascend again, and spend its time analyzing the sample up in the cool heights above. An exploration of terrains in the vicinity of 150 E, moving along the equator or 10 S -- could be a heck of a mission, with lots of geological and "remote" sensing of many terrains. Of course, if a pair of these things could be afforded, working at different latitudes but identical longitudes in the same time frame, then a very thorough exploration would result.
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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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