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Unmanned Spaceflight.com _ Venus _ Venera Images

Posted by: vikingmars Sep 14 2005, 09:26 PM

biggrin.gif Here is the Venera 13 fully calibrated image, produced from raw imaging 3-filters data (note the 3 horizons at left well discernible). It was published inside "L'Astronomie Magazine" of Societe Astronomique de France.
Enjoy !

 

Posted by: Decepticon Sep 14 2005, 09:31 PM

Wow! Nice work.

Posted by: um3k Sep 14 2005, 10:07 PM

Very nice!

Posted by: hal_9000 Sep 14 2005, 10:25 PM

WoW!

Posted by: gpurcell Sep 14 2005, 10:36 PM

QUOTE (vikingmars @ Sep 14 2005, 09:26 PM)
biggrin.gif Here is the Venera 13 fully calibrated image, produced from raw imaging 3-filters data (note the 3 horizons at left well discernible). It was published inside "L'Astronomie Magazine" of Societe Astronomique de France.
Enjoy !
*



Very, very nice!

Posted by: tedstryk Sep 15 2005, 12:18 AM

QUOTE (vikingmars @ Sep 14 2005, 09:26 PM)
biggrin.gif Here is the Venera 13 fully calibrated image, produced from raw imaging 3-filters data (note the 3 horizons at left well discernible). It was published inside "L'Astronomie Magazine" of Societe Astronomique de France.
Enjoy !
*


I am skeptical about that being a three image mosaic. I think that it is a three image mosaic merged with the clear channel scan. The color data simply isn't that good (The fact that the data is from Brown leads me to assume that it is the same set I use, because that is where I got mine). . Also, the color imagery doesn't extend out that far. Here is the best that can be produced with three frames.

The holes in the red image and some of the holes in the green image could be filled form two other images. It is also either scaled up or super-resolution - this is far bigger than the original image. I made a similar attempt and came up with this.




That said, it is an excellent image. I am assuming that whoever made this used the whole data set for a super-resolution product and produced color with the available images in each band.

Posted by: vikingmars Sep 15 2005, 07:18 AM

smile.gif Dear Tedstryk,
Yes, indeed, I had to reconstruct some missing data from different channels and adjust them for their wavelenghts, before integrating them to make the full final RGB color image. Also, the final product is somewat blowed-up because I had to make those fill-ins on a very precise up-to-the-pixel basis !

Posted by: tedstryk Sep 15 2005, 02:31 PM

QUOTE (vikingmars @ Sep 15 2005, 07:18 AM)
smile.gif Dear Tedstryk,
Yes, indeed, I had to reconstruct some missing data from different channels and adjust them for their wavelenghts, before integrating them to make the full final RGB color image. Also, the final product is somewat blowed-up because I had to make those fill-ins on a very precise up-to-the-pixel basis !
*


Great work!

Posted by: tedstryk Sep 19 2005, 05:17 PM

I have updated one of my mosaics from Venera 13. I have tried to do gap fill by guessing how features might continue from one side to the other.


Posted by: Decepticon Sep 19 2005, 09:45 PM

Now thats cool!

Posted by: GregM Sep 24 2005, 03:39 AM

.

Posted by: Decepticon Sep 24 2005, 05:05 AM

tedstryk I was wondering if you have ever edited the image so it would look as if I was standing on Venus?

I once saw a image like it in astronomy magazine but it was small.

Posted by: tedstryk Sep 24 2005, 12:33 PM

QUOTE (Decepticon @ Sep 24 2005, 05:05 AM)
tedstryk I was wondering if you have ever edited the image so it would look as if I was standing on Venus?

I once saw a image like it in astronomy magazine but it was small.
*



Other than http://pages.preferred.com/%7Etedstryk/venerac.html, I have found that frustrating. In addition to the wierd projection in terms of its shape, the fact that the camera turned so much as it scanned creat the appearance of everything being right in front of you. I remember an issue of Astronomy with some Venera images back in the late 1980s, but I think it was just the Venera 14 camera 1 picture that they showed.

Posted by: Bob Shaw Sep 24 2005, 02:48 PM

QUOTE (tedstryk @ Sep 24 2005, 01:33 PM)
Other than  http://pages.preferred.com/%7Etedstryk/venerac.html, I have found that frustrating.  In addition to the wierd projection in terms of its shape, the fact that the camera turned so much as it scanned creat the appearance of everything being right in front of you.  I remember an issue of Astronomy with some Venera images back in the late 1980s, but I think it was just the Venera 14 camera 1 picture that they showed.
*


The Soviets were very keen on 'epiphotography' - images made with a rotating turret and a slit rather than a traditional 'eye' design. They famously marketed the Horizont 35mm camera in the West which worked in this way, and is now a collectors item - it moved not only the optical barrel but the film as well, and you ended up with (I think) a 2X normal length negative. The geometry of such images - like those from the Viking Landers - is strange. All the data is there, but it all looks somehow *wrong*, as the perspective doesn't do what you expect. Such cameras were once very popular for school photographs, and produced a very high quality and long format print. Their mechanisms were sometimes slow enough for kids to race away behind the camera, come in from the other side, and be photographed twice!

Posted by: dvandorn Sep 24 2005, 04:02 PM

QUOTE (Bob Shaw @ Sep 24 2005, 09:48 AM)
...Such cameras were once very popular for school photographs, and produced a very high quality and long format print. Their mechanisms were sometimes slow enough for kids to race away behind the camera, come in from the other side, and be photographed twice!
*

As you could with the Viking cameras. There is an official Viking Imaging Team portrait out there somewhere, taken with one of the Viking cameras. At least one person appears in the picture three times. Several others appear in it twice.

-the other Doug

Posted by: djellison Sep 24 2005, 04:05 PM

QUOTE (dvandorn @ Sep 24 2005, 04:02 PM)
There is an official Viking Imaging Team portrait out there somewhere, taken with one of the Viking cameras.  At least one person appears in the picture three times.  Several others appear in it twice.

-the other Doug
*


http://history.nasa.gov/SP-425/ch8.htm


I've seen a larger version, and I think that actually, the guy who's on the bottom row - is on the image about 6 times

Doug

Posted by: JRehling Sep 24 2005, 04:39 PM

QUOTE (Decepticon @ Sep 23 2005, 10:05 PM)
tedstryk I was wondering if you have ever edited the image so it would look as if I was standing on Venus?

I once saw a image like it in astronomy magazine but it was small.
*


The net sum image data taken by a Venera camera would be properly compiled into a cup shape that shows you the horizon on the ends, and does *not* show you the horizon in the middle, but instead shows you the extreme foreground in the middle. Don Davis's sketch shows that cup shape in a grid across the middle of this image:

http://www.donaldedavis.com/2004%20new/VENERGRD.jpg

If the probes all landed straight up, it would be possible to neatly project their images into that cup shape, but if you try, you get results that are a bit off due to the tilt of the landers. I have played with these images to get acceptible looking cups, which I have stored on another computer than the one I'm using now. I frankly find them frustrating because the "best part", the middle horizon, is absent.

Venera 13 and 14 had two cameras facing opposite directions, and Ted's work shows the bits of horizon that are almost-contiguously captured by the side portions of the images.

There's really no better you can do with the raw data.

My attempt to use Venera images to give you the feeling of standing on Venus, I linked to here:

http://www.unmannedspaceflight.com/index.php?showtopic=909&st=75

As I said there, three of these images are 100% Venera brightness data, but I cloned and rearranged portions of the images so that any patch in my image is actual image data from that lander, true to the Y dimension, but slid around in the X to create a rectangular panorama with no gaps and pretty true to real Venus "stuff". The coloring is mainly fictional. The upper right image shows half of the Venera 10 "cup", which gives you an idea of what the whole set of 6 cups (1 each from Venera 9 and 10, 2 from Venera 13 and 14) would look like.

An all-real, non-fragmented panorama of Venus showing more than a bit of the horizon is simply impossible with Venera data. ESA hasn't said much about a Venus lander, so we'll probably see a first real panorama of Venus when the New Frontiers mission to Venus gets picked, which will either be fourth or fifth in that sequence of five (counting New Horizons as #1). That might happen around 2018-2025. A Discovery-class selection could perform that investigation (and others of great interest) but will likely not happen, IMO.

Posted by: Bob Shaw Sep 24 2005, 05:09 PM

QUOTE (djellison @ Sep 24 2005, 05:05 PM)
I've seen a larger version, and I think that actually, the guy who's on the bottom row - is on the image about 6 times

Doug
*



Doug:

Exactly!

And, if the image had been created in a setting other than that of a desert (ie with straight lines, buildings etc included) then you'd see the funny perspective, too...

Bob Shaw

Posted by: vikingmars Oct 4 2005, 08:00 PM

smile.gif Looking again closely at the Venera 13 camera 1 raw data, I made an small interesting (discovery : the lander has moved slightly between the 2nd and 3rd clear pans. So I did a quick pixel overlap between the 2nd and 5th clear pans to gain higher resolution.
Here it is (at right, compared to a "regular" image).
Unfortunately, this is the only segment available with no noise. To build an entire hi-res panoramic picture with no noise, I would need to fill in the gaps of the 2nd pan, with data from 3rd to 5th clear pan, thus useless to make hi-res !

...And see the prominent hill at the horizon !

biggrin.gif Enjoy the two pictures : (i) comparison and (ii) perspective oriented 45° to simulate what you would see if you were on Venus !

 

Posted by: vikingmars Oct 4 2005, 08:21 PM

biggrin.gif ...and I forgot to show you how the camera 1 pan looks like with all bad vertical noise removed by filling all the gaps !
Here it is (still as a raw version). Enjoy !


 

Posted by: ljk4-1 Oct 4 2005, 08:29 PM

QUOTE (vikingmars @ Oct 4 2005, 03:00 PM)
smile.gif Looking again closely at the Venera 13 camera 1 raw data, I made an small interesting (discovery : the lander has moved slightly between the 2nd and 3rd clear pans. So I did a quick pixel overlap between the 2nd and 5th clear pans to gain higher resolution.
Here it is (at right, compared to a "regular" image).
Unfortunately, this is the only segment available with no noise. To build an entire hi-res panoramic picture with no noise, I would need to fill in the gaps of the 2nd pan, with data from 3rd to 5th clear pan, thus useless to make hi-res !

...And see the prominent hill at the horizon !

biggrin.gif Enjoy the two pictures : (i) comparison and (ii) perspective oriented 45° to simulate what you would see if you were on Venus !
*


Venera 13 transmitted data from the planet's surface for 2 hours and 7 minutes, the longest of any lander there. And of all the landers that contained seismometers, only one detected what may have been a very faint and distant quake.

So this begs the question: If the lander movement was real, was it due to a surface movement, was it slipping off one of the rocks, perhaps because it was on a small hill or an angled rock - or was it pushed? cool.gif

Posted by: vikingmars Oct 4 2005, 08:50 PM

smile.gif Well ljk4-1... I don't know about the "Venusquake", but the lander movement is real.
See it herewith enlarged 400% (a shift of 2 pixels vertically between Clear pan 2 and Clear pan 5).

 

Posted by: tedstryk Oct 4 2005, 08:59 PM

QUOTE (vikingmars @ Oct 4 2005, 08:50 PM)
smile.gif Well ljk4-1... I don't know about the "Venusquake", but the lander movement is real.
See it herewith enlarged 400% (a shift of 2 pixels vertically between Clear pan 2 and Clear pan 5).
*


I can't tell if the lander has moved of the scanning mechanism has shifted. Don Mitchell suggested that there would be some shifting due to the expansion of spacecraft materials in the Venusian heat.

Posted by: ljk4-1 Oct 4 2005, 09:03 PM

QUOTE (vikingmars @ Oct 4 2005, 03:50 PM)
smile.gif Well ljk4-1... I don't know about the "Venusquake", but the lander movement is real.
See it herewith enlarged 400% (a shift of 2 pixels vertically between Clear pan 2 and Clear pan 5).
*


I am not questioning the veracity of the movement, but I do have these two questions:

1. What made Venera 13 move, especially in such a short time period?

2. Why hasn't this movement ever been brought to attention or noticed before? Or did I just miss something in the literature?

Always a treat to find something new, even in images over two decades old - which reminds me to say, it's about time we put some more landers on Venus!

Posted by: tedstryk Oct 4 2005, 10:21 PM

QUOTE (ljk4-1 @ Oct 4 2005, 09:03 PM)
I am not questioning the veracity of the movement, but I do have these two questions:

1.  What made Venera 13 move, especially in such a short time period?

2.  Why hasn't this movement ever been brought to attention or noticed before?  Or did I just miss something in the literature?

Always a treat to find something new, even in images over two decades old - which reminds me to say, it's about time we put some more landers on Venus!
*



It also may have shifted as it settled after landing. I don't think expansion and a slight change in the track of the scanning photometer can be ruled out.

Posted by: JRehling Oct 4 2005, 10:41 PM

QUOTE (tedstryk @ Oct 4 2005, 03:21 PM)
It also may have shifted as it settled after landing. I don't think expansion and a slight change in the track of the scanning photometer can be ruled out.
*


My bet is that something inside the spacecraft changed. Also, can we exclude the possibility of a 2-pixel shift due to some un-venus-related processing? I can think of scads of ways that postprocessing would lead to such a shift.

If something did take place on Venus, note that these landers were very heavy, and moreover, in comparison to the local environment, also very cold -- they may have caused some contraction of materials in immediate contact with them.

Posted by: Bob Shaw Oct 4 2005, 10:50 PM

QUOTE (vikingmars @ Oct 4 2005, 09:00 PM)
And see the prominent hill at the horizon !

*


That's just the rim of Gusev...

Posted by: Bob Shaw Oct 4 2005, 10:53 PM

QUOTE (JRehling @ Oct 4 2005, 11:41 PM)
My bet is that something inside the spacecraft changed.
*


Well, the scanning mechanism moved, the filters moved, the whole shooting match heated up... ...it's surely a tribute to the engineers that so few critical dimensions altered!

Posted by: RNeuhaus Oct 5 2005, 04:04 PM

QUOTE (Bob Shaw @ Oct 4 2005, 05:53 PM)
Well, the scanning mechanism moved, the filters moved, the whole shooting match heated up... ...it's surely a tribute to the engineers that so few critical dimensions altered!
*

The Venus's temperature is like to the kitchen oven. I am afraid that the Venera spaceship might still be in good shape....if it is made of kitchen oven's technology...

Rodolfo

Posted by: JRehling Oct 5 2005, 04:42 PM

QUOTE (RNeuhaus @ Oct 5 2005, 09:04 AM)
The Venus's temperature is like to the kitchen oven. I am afraid that the Venera spaceship might still be in good shape....if it is made of kitchen oven's technology...

Rodolfo
*


Well, it's quite a bit hotter than my kitchen's oven, but if the construction is mainly steel, or even aluminum, then all of the Veneras should externally look largely or even perfectly intact today, but many of the innards surely were sensitive to high temperatures. The idea was that thermal inertia would give the craft a time to work on the surface, until the first critical component failed. After that, other harm may have come as well. I suspect any earthly wiring insulation would drip away in venusian heat, although I don't know if the Soviets used a superior brand for Venera or if they merely calculated that something else would fail sooner.

It is enlightening to consider that many materials (sufficient even for some science instruments) can easily be made to withstand long stays in venusian heat. The problem is that electronics developed for that purpose do not exist, so the choice is either to expect short survival time, use a nuclear reactor to run a refrigeration system, invent the high-temperature electronics a craft would need -- or some combination of those three.

Posted by: ilbasso Oct 5 2005, 09:02 PM

Wasn't there also the thought that there is sulfuric acid rain on Venus? What would that do to a spaceship that was sitting there for a couple of months?

Posted by: RNeuhaus Oct 5 2005, 09:11 PM

How does the Venus has some kind of rain when the inside temperature is so hot that evaporates everything? There is nothing that can cool the atmosphere to make some rain?

Rodolfo

Posted by: tedstryk Oct 5 2005, 09:13 PM

QUOTE (RNeuhaus @ Oct 5 2005, 09:11 PM)
How does the Venus has some kind of rain when the inside temperature is so hot that evaporates everything? There is nothing that can cool the atmosphere to make some rain?

Rodolfo
*



There is no sulfuric acid rain on the surface of Venus. There has been speculation that it exists in the upper levels of the atmosphere. But in none of those models does it come anywhere near the surface before evaporating.

Posted by: helvick Oct 5 2005, 09:49 PM

QUOTE (tedstryk @ Oct 5 2005, 10:13 PM)
There is no sulfuric acid rain on the surface of Venus.  There has been speculation that it exists in the upper levels of the atmosphere.  But in none of those models does it come anywhere near the surface before evaporating.
*


And possiblyhttp://news-info.wustl.edu/news/page/normal/633.html on the mountain tops.

Ah yes - the ultimate in extreme skiing - hanging about on the top of Maxwell Montes, waiting for a fresh fall of galena powder on the southern piste. Peachy.

Posted by: vikingmars Oct 8 2005, 05:08 PM

(following item #19)
http://www.unmannedspaceflight.com/index.php?showtopic=1410&view=findpost&p=22733

smile.gif ...So, after verifying that there is also a 2-pixel shift visible on Venera 13 camera #2 images (between clear pans 1 and 2), I decided to apply my techniques building an hi-res Venera 13 color image from the data available.

I then built 2 different pancromatic pans : the 1st one from clear pan 1 (filling the gaps with green pan 1 and red 1 pan) and the 2nd one from clear pan 2 (filling the gaps with green pan 2 and red pan 2). Then I pixel-overlapped them to build an hi-res pancromatic pan. This one was then fused with the colors of the low-res picture (shown on item #1 : http://www.unmannedspaceflight.com/index.php?showtopic=1410&view=findpost&p=20445);

Here is the result : a gain of a 1.3-1.5 resolution over my previous color version.
I think it shows the maximum of details I can retrieve now from the V13 data.
Enjoy !

 

Posted by: RNeuhaus Oct 8 2005, 05:45 PM

QUOTE (vikingmars @ Oct 8 2005, 12:08 PM)
(following item #19)
http://www.unmannedspaceflight.com/index.php?showtopic=1410&view=findpost&p=22733

Precious picture
*

Posted by: Bob Shaw Oct 8 2005, 06:10 PM

Lovely image!

Bob Shaw

Posted by: ilbasso Oct 9 2005, 02:07 AM

Absolutely breathtaking! I'm amazed at the caliber of science that is represented on this site. You are all doing a tremendous service to all mankind by transcending international borders in your work. I'm honored and thrilled to be part of this forum!

Posted by: BruceMoomaw Oct 9 2005, 05:58 AM

QUOTE (tedstryk @ Oct 5 2005, 09:13 PM)
There is no sulfuric acid rain on the surface of Venus.  There has been speculation that it exists in the upper levels of the atmosphere.  But in none of those models does it come anywhere near the surface before evaporating.
*


It's more than "speculation"; it's been known fact for three decades. Venus' clouds are a mist of sulfuric acid, produced by the fact that the traces of sulfur dioxide dumped into its air by its still-actve volcanoes rise high into the atmosphere and are converted by solar UV into sulfur trioxide, which in turn reacts very readily with the remaining tracres of water vapor to form an H2SO4 cloud layer at the 64 to 46 km level. (This is the same process that created such large amounts of H2SO4 on early Mars, which as we now know has had a radical effect on its surface mineralogy.)

But:

(1) As one might expect, given the tiny trace amounts of the gases out of which they form, Venus' clouds are actually very rarified -- you could see through them for kilometers with little blurring. They are opaque to visible light as seen from above (or below) simply because the layer is so spatially thick (as is also the case with Titan's organic smog).

(2) Pioneer 13's biggest entry probe carried a cloud particle-size spectrometer which worked fine -- but detected not a single, solitary particle in Venus' air from 30 km altitude down to the surface.

(3) There are obviously other substances mixed in with the H2SO4 in Venus' clouds, whose identifies we do not know well, and which are subjects of major scientific interest. In particular, there's the stuff that makes so many regions of Venus' clouds look dark in UV photos -- we actually still do not know what this UV absorber is, although the favored theories revolve around its being one of several sulfur compounds. Then there's the possible detection by several of the Soviet landers of small amounts of other elements (Cl, P, and I think Fe) in the clouds, although given the accuracy of Soviet science instruments this is open to question. Finally, that same cloud particle-size spectrometer on Pioneer 13 located what seems to be a small separate population of cloud particles which are considerably larger than the other liquid acid droplets -- and may possibly be nonspherical solid crystals of something.

Posted by: RNeuhaus Oct 11 2005, 10:18 PM

I have found useful information about the Venera's design spacecraft. Visit http://www.russianspaceweb.com/venera75.html

Rodolfo

Posted by: vikingmars Oct 22 2005, 12:20 PM

(Thanks to all for your great contributions about atmospheric science !)

...and (following post 35), I decided to make an acknowledgement to the fantastic art work of Don Davis, by quickly correcting the perspective of the Venera 13 panorama, following his "Venera Grid" made in 1987.
Here is the Venera 13 "Daviscape" !
biggrin.gif Enjoy !

 

Posted by: tedstryk Jan 8 2006, 03:28 AM

Here is an attempt to do similar processing with a Venera 14 scan. This image has much poorer quality raw data, but, visually, it is my favorite of the Venera shots.



And here is a version with the spacecraft removed from the forground using cloning.


Posted by: PhilCo126 Jan 8 2006, 04:02 PM

Superb work on those 1982 Venera color panoramas!

Also great to see that Viking ITEK camera image again. When You look carefully You can see the late Dr Carl Sagan twice in that photo and Dr Thomas Mutch five times kneeling in front of the group ... ohmy.gif

Posted by: tedstryk Jan 9 2006, 02:33 PM

QUOTE (PhilCo126 @ Jan 8 2006, 04:02 PM)
Superb work on those 1982 Venera color panoramas!

Also great to see that Viking ITEK camera image again. When You look carefully You can see the late Dr Carl Sagan twice in that photo and Dr Thomas Mutch five times kneeling in front of the group ...  ohmy.gif
*


Thanks, but actually, I posted the wrong images. These are much better...




Posted by: RNeuhaus Jan 9 2006, 03:08 PM

Very different type of terrain. Mainly rocky, no sand or silica dust. No water erosion signs. Interesting.

Rodolfo

Posted by: JRehling Jan 9 2006, 08:29 PM

QUOTE (RNeuhaus @ Jan 9 2006, 07:08 AM)
Very different type of terrain. Mainly rocky, no sand or silica dust. No water erosion signs. Interesting.

Rodolfo
*


While these new presentations are aesthetically wonderful, the old, unnatural-looking presentations of Venera imagery allowed this level of observation, so they are not new to us. The four sites are quite different, with boulders atop/embedded in soil at two sites and large, plate sheets of rock at the other two. It is certainly the case that water erosion could not have acted on any portion of Venus's surface since the last major resurfacing event (if ever) -- if there are any ancient surfaces that show past water influence of any kind, we will have to hunt them down very carefully. Such formations may not exist at all.

There is sand/pebble soil visible in Venera 9 and Venera 13 surface views. Fine dust may be rare. It seems likely that chemical production of dust is not a major phenomenon, and mechanical processes that produce dust seem to be rare also. Because the surface temperature is very constant, there are only light winds, so dust will not beget new dust much.

Posted by: tedstryk Jan 9 2006, 08:34 PM

QUOTE (JRehling @ Jan 9 2006, 08:29 PM)
While these new presentations are aesthetically wonderful, the old, unnatural-looking presentations of Venera imagery allowed this level of observation, so they are not new to us. The four sites are quite different, with boulders atop/embedded in soil at two sites and large, plate sheets of rock at the other two. It is certainly the case that water erosion could not have acted on any portion of Venus's surface since the last major resurfacing event (if ever) -- if there are any ancient surfaces that show past water influence of any kind, we will have to hunt them down very carefully. Such formations may not exist at all.

There is sand/pebble soil visible in Venera 9 and Venera 13 surface views. Fine dust may be rare. It seems likely that chemical production of dust is not a major phenomenon, and mechanical processes that produce dust seem to be rare also. Because the surface temperature is very constant, there are only light winds, so dust will not beget new dust much.
*


I have always thought the Venera 9 site looks like a Viking landing site.

Posted by: RNeuhaus Jan 9 2006, 09:22 PM

I think that the dust is the product of desintegration of rocks due to some kind of erosion of wind, water, or land along with the temperature changes, or chemical reaction. May be due to the radioactive decay of minerals that desintegrate the rocks into the dust.

So, Venus has "no water", on the surface has very low wind speed and very low temperature changes (I doubt it, since Venus has night that I don't know how much is the temperature drop between the day (470 Centigrade) and night ??. The rest venusian dust might be due to the chemical reaction or radioactive decay of some rocks?

Rodolfo

Posted by: JRehling Jan 9 2006, 10:14 PM

QUOTE (RNeuhaus @ Jan 9 2006, 01:22 PM)
So, Venus has "no water", on the surface has very low wind speed and very low temperature changes (I doubt it, since Venus has night that I don't know how much is the temperature drop between the day (470 Centigrade) and night ??. 
*


I'm curious -- if you don't know how much the temperature drop is between night and day on Venus, but you are interested enough to discuss the matter, why don't you look it up on the Internet before posting?

It seems odd to me that a poster perceiving himself to lack information would have a greater motivation to analyze a phenomenon (and post the un-informed analysis) than to get basic information about the phenomenon. The information is not hard to come by, and un-informed analysis is all too easy to come by! wink.gif

Put another way: If you have ten units of personal energy, which do you think helps the board more: five researched topics and five informed posts, or ten uninformed posts?

Posted by: Bob Shaw Jan 9 2006, 11:10 PM

QUOTE (tedstryk @ Jan 9 2006, 09:34 PM)
I have always thought the Venera 9 site looks like a Viking landing site.
*


Or even the latest Meridiani images!

Bob Shaw

Posted by: tedstryk Jan 9 2006, 11:12 PM

QUOTE (Bob Shaw @ Jan 9 2006, 11:10 PM)
Or even the latest Meridiani images!

Bob Shaw
*


I think Venera 13 is more Meridiani-ish.

Posted by: Bob Shaw Jan 9 2006, 11:24 PM

QUOTE (tedstryk @ Jan 10 2006, 12:12 AM)
I think Venera 13 is more Meridiani-ish.
*


Yes. My mistake!

Now, if you can pull some festoon bedding out of those old Soviet images...

Bob Shaw

Posted by: tedstryk Jan 10 2006, 02:43 AM

Here is a Venera 14 compilation. I can't get much of a super-resolution effect out of camera 2 (the full color pan), owing to the really crappy quality of the original images.

http://img363.imageshack.us/my.php?image=v14combo4cm.jpg

Posted by: BruceMoomaw Jan 10 2006, 03:01 AM

The consensus now is that what we're seeing in both the Venera 13 and 14 photos (and probably those from Venera 9 and 10) is not regular rock, but sheets of fine dust (probably impact ejecta) that's been fused into layers of friable rock by the chemical reactions that go on between soil grains and the trace gases in Venus' super-hot, super-pressurized atmosphere. Both the Venera 9 and 10 density measurements and Venera 13's penetrometer revealed the stuff to be lower in density and hardness than regular basalt (I never thought those instruments would reveal anything interesting, but they did). And this presumably explains the startling absence of any signs of aeolian movement in Magellan's images, despite the fact that Venus' low surface breeze of just 1 meter/sec should have been enough to move dust and sand around on its surface. As it is, the only dunes we see on Venus seem to be those piled up around giant impact craters, presumably by the air blast associated with each impact.

I have, when I can find it, a conference abstract on the simulation of this fusion process in an Earth lab.

Posted by: JRehling Jan 10 2006, 03:04 AM

QUOTE (tedstryk @ Jan 9 2006, 03:12 PM)
I think Venera 13 is more Meridiani-ish.
*


Venera 14 looks like someone took a vacuum cleaner to Meridiani.

It's striking how much, at a glance, the Huygens surface picture looks like Venera 9's.

It's also interesting that Venus, Mars, and Titan all have orangeish light coming through their atmospheres. If you want to see another world with a blue, purple, green, yellow, or red sky, you're going to have to try another solar system.

Posted by: tedstryk Jan 10 2006, 03:16 AM

QUOTE (JRehling @ Jan 10 2006, 03:04 AM)
Venera 14 looks like someone took a vacuum cleaner to Meridiani.

It's striking how much, at a glance, the Huygens surface picture looks like Venera 9's.

It's also interesting that Venus, Mars, and Titan all have orangeish light coming through their atmospheres. If you want to see another world with a blue, purple, green, yellow, or red sky, you're going to have to try another solar system.
*


Unless perhaps you are on a blimp in the atmosphere or Uranus or Neptune, which I am assuming would produce a blue sky.

Seriously, it is caused by an interesting set of circumstances. Earth's sky appears blue because blue light is more easily scattered, while red light makes it to the surface with less trouble. Venus is so good at scattering that hardly any blue light reaches the surface. I am guessing that Titan is similar, although, unlike Venus, I have not seen spectra (which must exist from Huygens). Venus and Titan of course have thicker atmospheres than Earth. Mars should certainly have a blue sky, it was surmised by Viking scientists, but suspended red dust wrecks havoc on the idea. I think truely green or yellow skies are going to be rare in the universe. Blue (which I am assuming would be Violet if the human eye weren't more sensitive to blue light) and red are end members of the visible spectrum, meaning that blue/violet and red skies could mean true peaks in infrared or ultraviolet. To be green or yellow, the peak would have to truely be in that spectral range.

Posted by: tedstryk Jan 10 2006, 05:02 AM

Here is the completed version of that set. Because it was a particularly good area in the data, I made an even more enlarged version of that peculiar rock in the camera 2 pan. Also, I colorized the area for which there was no color data.

http://img370.imageshack.us/my.php?image=v14combob1hv.jpg

Posted by: RNeuhaus Jan 10 2006, 04:24 PM

QUOTE (JRehling @ Jan 9 2006, 05:14 PM)
I'm curious -- if you don't know how much the temperature drop is between night and day on Venus, but you are interested enough to discuss the matter, why don't you look it up on the Internet before posting?

It seems odd to me that a poster perceiving himself to lack information would have a greater motivation to analyze a phenomenon (and post the un-informed analysis) than to get basic information about the phenomenon. The information is not hard to come by, and un-informed analysis is all too easy to come by!  wink.gif

Put another way: If you have ten units of personal energy, which do you think helps the board more: five researched topics and five informed posts, or ten uninformed posts?
*

You are right,. I posted for someone if I know in others topics. The easiest thing is to ask someone if he knows.

I have already searched and it seems that there is no surface temperature statistics between day and night. There is only temperature information that is related to the altitude.

I realized that the only one temperature might be due to the greenhouse effect has kept the surface temperature to be more or less constant between day and night.


Venera 7 has no information about the landing place and position to the Sun.

Venera 8 landed at 09:32 UT at 10 degrees south, 335 degrees west, in sunlight about 500 km from the morning terminator. The lander mass was 495 kg. It continued to send back data for 50 minutes, 11 seconds after landing before failing due to the harsh surface conditions. The probe confirmed the earlier data on the high Venus surface temperature and pressure (470 degrees C, 90 atmospheres) returned by Venera 7, and also measured the light level as being suitable for surface photography, finding it to be similar to the amount of light on Earth on an overcast day with roughly 1 km visibility.

Venera 9: The landing was about 2,200 km from the Venera 10 landing site. The Lander touched down on the surface of Venus on October 22, 1975 at 5:13 UT, about 32° S, 291° E with the sun near zenith. It operated for 53 minutes, allowing return of a single image. Venera 9 landed on a slope inclined by about 30 degrees to the horizontal.Preliminary results indicated: (A) clouds 30-40 km thick with bases at 30-35 km altitude, (cool.gif atmospheric constituents including HCl, HF, Br, and I, © surface pressure about 90 (earth) atmospheres, (D) surface temperature 485 deg C, (E) light levels comparable to those at earth midlatitudes on a cloudy summer day, and (F) successful TV photography showing shadows, no apparent dust in the air, and a variety of 30-40 cm rocks which were not eroded.

Venera 10:The landing was about 2,200 km distant from Venera 9. The Venera 10 Lander (bottom) touched down on the surface of Venus on October 25, 1975 at 5:17 UT, about 16° N, 291° E. The Lander was inclined about 8 degrees. It returned this image during the 65 minutes of operation on the surface. The sun was near zenith during this time, and the lighting was similar to that on Earth on an overcast summer day. Preliminary results provided: (A) profile of altitude (km)/pressure (earth atmospheres)/temperature (deg C) of 42/3.3/158, 15/37/363, and 0/92/465, (cool.gif successful TV photography showing large pancake rocks with lava or other weathered rocks in between, and © surface wind speed of 3.5 m/s.

Venera 11: It made a soft landing on the surface at 06:24 Moscow time on 25 December after a descent time of approximately 1 hour. The touchdown speed was 7-8 m/s. Information was transmitted to the flight platform for retransmittal to earth until it moved out of range 95 minutes after touchdown. Seem to be failed to transmit data.

Venera 12: The touchdown speed was 7-8 m/s. Information was transmitted to the flight platform for retransmittal to earth. until it moved out of range 110 minutes after touchdown. (no information about landing place).

Venera 13: . Venera 13 landed about 950 km northeast of Venera 14 at 7 deg 30 min S, 303 E, just east of the eastern extension of an elevated region known as Phoebe Regio. The area was composed of bedrock outcrops surrounded by dark, fine-grained soil. After landing an imaging panorama was started and a mechanical drilling arm reached to the surface and obtained a sample, which was deposited in a hermetically sealed chamber, maintained at 30 degrees C and a pressure of about .05 atmospheres. The composition of the sample determined by the X-ray flourescence spectrometer put it in the class of weakly differentiated melanocratic alkaline gabbroids. The lander survived for 127 minutes (the planned design life was 32 minutes) in an environment with a temperature of 457 degrees C and a pressure of 84 Earth atmospheres. The descent vehicle transmitted data to the bus, which acted as a data relay as it flew by Venus.

Venera 14: Venera 14 landed about 950 km southwest of Venera 13 near the eastern flank of Phoebe Regio at 13 deg 15 min S by 310 E on a basaltic plain. After landing an imaging panorama was started and a mechanical drilling arm reached to the surface and obtained a sample, which was deposited in a hermetically sealed chamber, maintained at 30 degrees C and a pressure of about .05 atmospheres. The composition of the sample was determined by the X-ray flourescence spectrometer, showing it to be similar to oceanic tholeiitic basalts. The lander survived for 57 minutes (the planned design life was 32 minutes) in an environment with a temperature of 465 degrees C and a pressure of 94 Earth atmospheres. The descent vehicle transmitted data to the bus, which acted as a data relay as it flew by Venus.


I suppose that the maximum and minimum Venus temperature (mean surface temperature is between 464 and 482 celius degree). These measured temperature corresponds to close to equatorial latitud between 10 and 31 degree South and the Sun was near Zenith during this time (above head).

I am thinking that the polar surface sites must have a slight less temperature, perhaps 450 Celius degree, than the equatorial lines due to greenhouse effect?

Good details about Venus http://www.solarviews.com/eng/venus.htm

Rodolfo



Rodolfo

Posted by: ljk4-1 Jan 10 2006, 04:26 PM

QUOTE (RNeuhaus @ Jan 10 2006, 11:24 AM)
You are right,. I posted for someone if I know in others topics.  The easiest thing is to ask someone if he knows.

I have already searched and it seems that there is no surface temperature statistics between day and night. There is only temperature information is related to the altitude.

I realized that the only one temperature might be due to the greenhouse effect has kept the surface temperature to be more or less constant between day and night.

...

I suppose that the maximum and minimum Venus temperature (mean surface temperature is between 464 and 482 celius degree). These measured temperature corresponds to close to equatorial latitud between 10 and 13 degree South.

I am thinking that the polar surface sites must have a slight less temperature, perhaps 450 Celius degree, than the equatorial lines due to greenhouse effect?

Rodolfo
*


I know I should double-check this, but I remember reading that Venus' surface is actually warmer at its poles than its equator, plus its night side is warmer than the day side!

Either I am right or I am operating on a 20-year-old memory/data.

Posted by: RNeuhaus Jan 10 2006, 04:57 PM

QUOTE (ljk4-1 @ Jan 10 2006, 11:26 AM)
I know I should double-check this, but I remember reading that Venus' surface is actually warmer at its poles than its equator, plus its night side is warmer than the day side!

Either I am right or I am operating on a 20-year-old memory/data.
*

Why such strange physics laws?

Venus has very small Tilt of axis (degrees 177.36), so Venus has no typical summer and winter and the temperature in Equatorial line must be warmer all round year and the poles which are not zenith and receive less solar energy and consequently must be cooler but the greenhouse effect might alter these physics laws.

Why is warmer at its poles than its equator and also of nights versus days?
It would be very good that you find the link about the above odd behavior.

Rodolfo

Posted by: tasp Jan 10 2006, 06:30 PM

{ I hope I phrase this well enough }

Does any one know the cooling rate for 'earth type' basaltic magma from the time of contact with liquid water to the point it has solidified as compared to the expected cooling rate for the Venusian equivalent of basaltic magma from the time of contact with the Venusian atmosphere to the point of solidification?

Is 1300 psi (or whatever it works out to) CO2 more heat absorbing than H2O at 15 psi ?

Funny if the magma on Venus solidifies faster than the magma on earth in contact with sea water.

Would this effect the forms of the rocks we expect to see?

Posted by: JRehling Jan 10 2006, 06:50 PM

QUOTE (tasp @ Jan 10 2006, 10:30 AM)
{ I hope I phrase this well enough }

Does any one know the cooling rate for 'earth type' basaltic magma from the time of contact with liquid water to the point it has solidified as compared to the expected cooling rate for the Venusian equivalent of basaltic magma from the time of contact with the Venusian atmosphere to the point of solidification?

Is 1300 psi (or whatever it works out to) CO2 more heat absorbing than H2O at 15 psi ?

Funny if the magma on Venus solidifies faster than the magma on earth in contact with sea water.

Would this effect the forms of the rocks we expect to see?
*


Sea water on Earth is only at 15 psi at the shoreline (eg, on a beach). The pressure is much higher in locations of typical seafloor magma exposure, and would certainly have a much higher thermal inertia than Venus's CO2. It's also much cooler, which is another factor in the speed of heat propagation.

Water, even at 15 psi, is roughly 1000 times as dense as Earth air. Sea water is even denser. Venus's surface atmosphere is very roughly (no time for math now!) 75 times as dense as Earth air.

Anyone who has stood in a 10 km/h breeze and has also been hit by a 10 km/h ocean wave will appreciate the vast difference. Venus's atmosphere is in the middle.

Posted by: RNeuhaus Jan 10 2006, 07:30 PM

QUOTE (RNeuhaus @ Jan 10 2006, 11:57 AM)
Why such strange physics laws? 

Venus has very small Tilt of axis (degrees 177.36), so Venus has no typical summer and winter and the temperature in Equatorial line must be warmer all round year and the poles which are not zenith and receive less solar energy and consequently must be cooler but the greenhouse effect might alter these physics laws. 

Why is warmer at its poles than its equator and also of nights versus days?
It would be very good that you find the link about the above odd behavior.

Rodolfo
*

I found an article which mentions about the temperature of day and night and also of polars: The polar temperature is compensated by the thermal regime of Venus in spite of the fact of the temperatures inhomogenitis between equator and poles that arise from the differential insolation. On the other hand, the night-side temperatures exceed day-side temperatures according to the authors. The thermal asymmetry of Venus was confirmed by data from infrarred radiometry on Venera 9 and Venera 10 orbiters, and in particular from the analysis of limb darkening. The variation of temperature between day and night is due mainly to a change in height of the emissivity layer in the vicinity of upper cloud deck (65-68 km).

Interesting smile.gif

http://articles.adsabs.harvard.edu//full/seri/ARA%2BA/0016//0000157.000.html

Rodolfo

Posted by: tedstryk Jan 11 2006, 02:49 PM

Here are two more shots. An improved horizon pan:



And an improved version of that cool looking rock formation.


Posted by: paxdan Jan 11 2006, 04:02 PM

Looks to me that if you flipped the rock over it matches with the surface immediately above it

Posted by: tedstryk Jan 11 2006, 04:35 PM

QUOTE (paxdan @ Jan 11 2006, 04:02 PM)
Looks to me that if you flipped the rock over it matches with the surface immediately above it
*


The only problem is that in the full pan, there are many spots that look like the area above the formation with no rock sitting next to them.

Posted by: Michael Capobianco Jan 11 2006, 05:00 PM

Does anyone else remember the "fact" that refraction in the dense Venusian atmosphere would be so strong that you could see the back of your own head? I remember puzzling over that for hours as a kid, but I never really believed it.

Michael


QUOTE (JRehling @ Jan 10 2006, 01:50 PM)
Sea water on Earth is only at 15 psi at the shoreline (eg, on a beach). The pressure is much higher in locations of typical seafloor magma exposure, and would certainly have a much higher thermal inertia than Venus's CO2. It's also much cooler, which is another factor in the speed of heat propagation.

Water, even at 15 psi, is roughly 1000 times as dense as Earth air. Sea water is even denser. Venus's surface atmosphere is very roughly (no time for math now!) 75 times as dense as Earth air.

Anyone who has stood in a 10 km/h breeze and has also been hit by a 10 km/h ocean wave will appreciate the vast difference. Venus's atmosphere is in the middle.
*

Posted by: Toma B Jan 11 2006, 05:13 PM

I heard about refraction in Venusian atmosphere...something like "you would have feeling that you are walkin at the bottom of crater with very steep walls even if you are on flat ground...don't remember quite well about that but, seeing the back of your own head????I HAVE NEVER HEARD SOMETHING LIKE THAT...please explain...

Posted by: tedstryk Jan 11 2006, 05:41 PM

QUOTE (Toma B @ Jan 11 2006, 05:13 PM)
I heard about refraction in Venusian atmosphere...something like "you would have feeling that you are walkin at the bottom of crater with very steep walls even if you are on flat ground...don't remember quite well about that but, seeing the back of your own head????I HAVE NEVER HEARD SOMETHING LIKE THAT...please explain...
*



That was an old theory, but turned out not to be the case. The Veneras showed the horizon just where it should be, when corrected for their odd imaging system.

Posted by: helvick Jan 11 2006, 06:43 PM

QUOTE (Toma B @ Jan 11 2006, 06:13 PM)
I heard about refraction in Venusian atmosphere...something like "you would have feeling that you are walkin at the bottom of crater with very steep walls even if you are on flat ground.
*

I seriously doubt that.

For starters refraction effects happen at interfaces or across density gradients. For the sort of effects described here you would need to have really bizarre density gradients all around you.

Things would probably look a bit different and heat shimmer effects might be more pronounced than on earth but they would be far less extreme than under water on earth for example.

The refractive index of CO2 at STP is 1.000449 (air is 1.000292). The refractive index of a gas changes (very approximately) with density according to (RIx=1+(RIstp-1)*(Dx/Dstp) so the RI of the venusian surface atmosphere is somewhere around 1.04041 (since the Venusian surface atmospheric density is approximately 90x the density of CO2 at STP).

Snells law gives us something to calculate what this would mean for a human in a spacesuit on the surface of Venus. Assuming we have an optically neutral window and we simplify the calculation down to an air (at stp) CO2 (at Venus surface) boundary.
Snell's law : RIi*Sin(Thetai)=RIr*Sin(Thetar)
Thetai = Incident beam angle and Thetar= Refracted beam angle
So Sin(Thetar)=1.000292*(sin(45deg)/1.04041
The refracted beam would be at 42.8deg. Noticable but not significant.
As a comparison for a water:air interface on earth the equivalent refracted beam would be at 32.9deg.

All in all it might be hard to play pool well on the surface of Venus but it certainly wouldn't create any bizarre visual effects.

Posted by: JRehling Jan 11 2006, 07:06 PM

QUOTE (helvick @ Jan 11 2006, 10:43 AM)
All in all it might be hard to play pool well on the surface of Venus but it certainly wouldn't create any bizarre visual effects.
*


Unless you count two scorched and imploded skeletons slumped over an incinerated pool table as a bizarre visual effect.

Posted by: ljk4-1 Jan 11 2006, 07:20 PM

Don Dixon made some paintings of the alleged super refraction of Venus' atmosphere from the surface here:

http://www.cosmographica.com/gallery/portfolio/portfolio051/pages/096-%20Superrefraction%20.htm

http://www.cosmographica.com/gallery/portfolio/portfolio051/pages/097-Inferno.htm

As a bonus, here is Dixon's rendition of what the Pioneer Venus Day Probe probably looked like as it sat on the planet's surface and radioed back to Earth for 67 minutes in 1978:

http://www.cosmographica.com/gallery/portfolio/portfolio051/pages/100-VenusLanding.htm

Posted by: Toma B Jan 11 2006, 07:27 PM

QUOTE (ljk4-1 @ Jan 11 2006, 10:20 PM)
Don Dixon made some paintings of the alleged super refraction of Venus' atmosphere from the surface here:
*

...but now we know that's not true don't we? sad.gif
ljk thank you for that links....those images really rock!!!

Posted by: ljk4-1 Jan 11 2006, 07:29 PM

QUOTE (Toma B @ Jan 11 2006, 02:27 PM)
...but now we know that's not true don't we? sad.gif
*


Yes, if you will note from his headers, the paintings were made in the 1968 to 1974 period, and Dixon even labels one as outdated.

I just thought since super refraction was being talked about here, some folks might enjoy seeing a Venus that never was. smile.gif

Posted by: BruceMoomaw Jan 12 2006, 01:47 AM

Yes, the first shots of Venus from Venera 9 and 10 turned out to be remarkable for their sheer ordinariness. Not only was there no super-refractive "swimming pool effect" (which had recently become a staple of SF stories about the planet; John Varley's first published story used it and was called "In the Bowl"), but even in those grainy photos it was clear that the horizon was fairly sharp and that the shadows even of small pebbles, despite the dense atmosphere, were quite sharp. In fact, the Soviets had equipped the two landers with floodlights on the assumption that the solar illumination might be too dim to see the surface otherwise! The much better photos from Venera 13 and 14, of course, confirmed all this even more dramatically (and also revealed that fiery orange sky, although I don't know whether that color was predicted in advance).

Scientists have, really, a pretty bad track record when it comes to predicting the optical qualities of surface photos. Remember how astonished everyone was when Viking 1's first black-and-white photos showed a light-colored sky (which later turned out to be pink) instead of the deep violet sky everyone had expected? They even predicted that deep violet sky again for Pathfinder, since there was less dust in the air at the time of its landing.

Posted by: ljk4-1 Jan 12 2006, 05:53 PM

QUOTE (BruceMoomaw @ Jan 11 2006, 08:47 PM)
Yes, the first shots of Venus from Venera 9 and 10 turned out to be remarkable for their sheer ordinariness.  Not only was there no super-refractive "swimming pool effect" (which had recently become a staple of SF stories about the planet; John Varley's first published story used it and was called "In the Bowl"), but even in those grainy photos it was clear that the horizon was fairly sharp and that the  shadows even of small pebbles, despite the dense atmosphere, were quite sharp.  In fact, the Soviets had equipped the two landers with floodlights on the assumption that the solar illumination might be too dim to see the surface otherwise!  The much better photos from Venera 13 and 14, of course, confirmed all this even more dramatically (and also revealed that fiery orange sky, although I don't know whether that color was predicted in advance). 
*


The big reason Soviet scientists thought Venus would be so dark at its surface is that the Venera 8 lander reported dim lighting conditions in 1972. Venera 8 did this with cadmium sulfide photoresistors (try to fit that phrase into your next dinner conversation), as it carried no cameras.

But what they did not seem to take into account was that the Sun was only 5 degrees above the horizon at the Venera 8 landing site when the readings were taken.

ftp://ftp.seds.org/pub/info/newsletters/ejasa/1993/jasa9303.txt

Posted by: ljk4-1 Jan 23 2006, 05:08 PM

Soviet Veneras and Mars: first entry probes trajectory reconstruction and science

Viktor Kerzhanovich, Jet Propulsion Laboratory,
Pasadena, CA, USA

Konstantin Pichkhadze, Lavochkin Association,
Moscow, Russia

Presented to International Workshop on Planetary
Probe Atmospheric Entry and Descent Trajectory
Analysis and Science

Lisbon, Portugal, 6-9 October 2003

http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37338/1/03

Though most of the data and probe images are on the Veneras, there are some very nice diagrams of Mars 3 and 6 and data charts on the Martian atmosphere from Mars 6.

Posted by: tedstryk Jan 23 2006, 06:07 PM

Great find! I had seen the Mars 6 stuff in an old 1977 paper he wrote in Icarus, but good to see that the dataset is being presented again. Regardless of overall value, it is the first in situ data (other than the mysterious Mars 3 blurb) from the Martian atmosphere and there are only five other decent profiles in existence - it would be a pitty for it to be totally forgotten.

Posted by: ljk4-1 Jun 3 2006, 08:34 PM

Found this Soviet document from 1969 on their Venera missions up to
Venera 6. Some nice and uncommon (for the West) artwork and diagrams:

http://epizodsspace.testpilot.ru/bibl/venera/obl.html


This whole site is a gold mine of old and not so old Soviet space books
and documents - most of it in Russian, oddly enough:

http://epizodsspace.testpilot.ru/bibl/biblioteka.htm

http://epizodsspace.testpilot.ru/bibl/oblojki/oblojki.html

Posted by: DonPMitchell Jun 4 2006, 03:13 AM

QUOTE (ljk4-1 @ Jun 3 2006, 01:34 PM) *
Found this Soviet document from 1969 on their Venera missions up to
Venera 6. Some nice and uncommon (for the West) artwork and diagrams:

http://epizodsspace.testpilot.ru/bibl/venera/obl.html
This whole site is a gold mine of old and not so old Soviet space books
and documents - most of it in Russian, oddly enough:

http://epizodsspace.testpilot.ru/bibl/biblioteka.htm

http://epizodsspace.testpilot.ru/bibl/oblojki/oblojki.html


Yep, that site has been around for some years. Sergey Khlynin did most of the work. He's been a big help to me in my research, especially making some special high-res scans of rare photos.

Posted by: Rakhir Sep 11 2006, 04:15 PM

Don,

your images are amazing ! ohmy.gif

http://www.space.com/scienceastronomy/060911_venus_images.html

Posted by: dilo Sep 11 2006, 07:23 PM

To many things are happening today...
These Venera(ble) images are breathtaking ohmy.gif , I'm impressed by the atmosphere transparency...
Beautiful! We must send a MER (VER) there... rolleyes.gif

Posted by: Stu Sep 11 2006, 10:10 PM

Congratulations on being featured on SPACE.com Don! About time your fantastic images were seen by a wider audience. The one of the hills is literally breathtaking.

Posted by: climber Sep 11 2006, 11:17 PM

QUOTE (Stu @ Sep 12 2006, 12:10 AM) *
The one of the hills is literally breathtaking.

Yep! Here too, we can near rim, far rim and far-far rim wink.gif
Seriously, been used of the original pictures, I've got the feeling to discover a new word. Kind of going from "Phil's polars" to Dilo's, Midnigth Mars, etc...
Thanks so much and congratulations Don.

Posted by: tedstryk Sep 11 2006, 11:52 PM

Congratulations! It is great to see the images in a human perspective.

Posted by: DonPMitchell Sep 11 2006, 11:58 PM

Thanks guys. NBC picked up the story too (http://www.msnbc.msn.com/id/14786868/). Interesting to see how they fiddled with Leonard's wording and my quotes, and kind of broke most of them. :-)

I'll add a blog entry on my site with a little more explaination about the images.

Posted by: DFinfrock Sep 12 2006, 01:03 AM

Don,

Those old Venera images were always appreciated for the close up views of the rocks scattered around the landers. But after viewing your versions, with hills and real horizons, Venus has become a real PLACE for me, just as Gusev and Meridiani are real places. Thanks so much. Your efforts are really appreciated.

David

Posted by: DonPMitchell Sep 12 2006, 01:28 AM

Thanks, it was an afterthought really, but I'm glad I did it. My brain definately sees the terrain better in perspective, even though I am not seeing an new pixels.

I added a little extra info about the project on my blog: http://donpmitchell.blogspot.com/

Posted by: dvandorn Sep 12 2006, 02:26 AM

Yes, thanks, Don! In particular, the "hills" remind me a lot of a lava dike that has breached and allowed a fan-shaped flow of lava to come in and pave the area upon which the lander sits.

Fascinating place!

-the other Doug

Posted by: RNeuhaus Sep 12 2006, 03:01 AM

I was delighted to see Don's Pictures. I couldn't believe it since I have seen a partial picture. Below the Venusian atmosphere looks so transparent even many kilometers.

Rodolfo

Posted by: mcaplinger Sep 12 2006, 04:40 AM

QUOTE (DonPMitchell @ Sep 11 2006, 06:28 PM) *
I added a little extra info about the project on my blog: http://donpmitchell.blogspot.com/

Very interesting and well-done. One question: the "channel" in the mid-field of the image on your blog page seems suspiciously aligned with the edges of the image coverage. Is there really reason to think this is anything but an artifact of your processing? I wouldn't want people doing photogeology on the basis of seeing this feature if there isn't real evidence for it.

Posted by: DonPMitchell Sep 12 2006, 06:26 AM

QUOTE (mcaplinger @ Sep 11 2006, 09:40 PM) *
Very interesting and well-done. One question: the "channel" in the mid-field of the image on your blog page seems suspiciously aligned with the edges of the image coverage. Is there really reason to think this is anything but an artifact of your processing? I wouldn't want people doing photogeology on the basis of seeing this feature if there isn't real evidence for it.


The persective images are derived from superimposing different projections, with photoshop. I explain that on my latest blog entry. Geologists would not use an image like that to do any kind of analysis. They are just meant to convey the big picture of what the terrain looks like, in a familiar camera perspective. For photo interpretation of geology, you would look at the new unprojected images, with the improved radiometric response function, or even the individual perspective projections, like the three partitial images I show.

Soviet researches, at one time, reprojected the Venera images into the cylindrical form returned by the Viking Mars lander, to help make comparisons in a projection that planetary geologists had become use to studying.

Posted by: AndyG Sep 12 2006, 08:40 AM

Well done, Don.

You've managed to make me beat my shortest-lived wallpaper ever record, when yesterday's stunning http://www.lpod.org/?m=20060911 shot was bumped off my monitors this morning to be replaced with your Venusian Hills.

Beautiful imagery - I have to agree with David with regards to making Venus a place, with work as good as this.

Andy

Posted by: dilo Sep 12 2006, 11:01 AM

Don, my first attempt to produce vertical/polar projections showed unacceptable distorsion in the lower part, due to the fact that your image isn't an equirectangular projection but is probably closer to a wide-angle image with rectilinear correction (like some processed hazard cam images from MER).
After applying to the original some "pincushion" distorsion and assuming 90 deg FOV, results appear better (vertical projections for V13 and 14 respectively):


Do not know real scale (should be a 0.5cm/pixel assuming a camera height of 1m); someone can calculate based on the probe features...
Here the corresponding pseudo-polars:

Posted by: DonPMitchell Sep 12 2006, 11:42 AM

The images were originally 800 x 600, and the sky was later extended by 200 pixels. So the camera is perspective projection, but it is pointing downward a little. Just delete the upper 200 pixels and try. Here is the code that made the image:

CODE
//
//  Take a picture with a perspective camera
//
#define NWIDE 800
#define NHIGH 600

static void
Camera(double fTheta, double fPhi, char *sz)
{
    ML_Vector3 v;
    double x, y, z;
    ML_Image im;
    ML_Matrix3x3 matTilt;
    int i, j;

    im.NewImage(NWIDE, NHIGH, 1);
    matTilt = ML_EulerMatrix(fPhi*D_DTR, 0.0, fTheta*D_DTR, "xyz");
    y = 0.45 * double(NWIDE);
    for (i = 0; i < NWIDE; i++) {
        x = double(i - NWIDE/2) + 0.5;
        for (j = 0; j < NHIGH; j++) {
            z = -double(j - NHIGH/2) - 0.5;
            v = ML_Vector3(x, y, z);
            v = matTilt * v;
            v = s_matCamera * v;
            im.Set(SampleVector(v), i, j);
        }
    }
    im.WriteBMP(sz);
}

Posted by: mars loon Sep 12 2006, 12:15 PM

Don,

beautiful work. fantastic hills. I will now plan to show them at our astronomy club meeting in Princeton tonight as part of a review of recent discoveries and the Viking 30th anniversary

ken

http://www.princetonastronomy.org/

Posted by: mcaplinger Sep 12 2006, 01:57 PM

QUOTE (DonPMitchell @ Sep 11 2006, 11:26 PM) *
Geologists would not use an image like that to do any kind of analysis.

You haven't worked with a lot of geologists, have you? smile.gif

Posted by: DonPMitchell Sep 12 2006, 03:56 PM

QUOTE (mcaplinger @ Sep 12 2006, 06:57 AM) *
You haven't worked with a lot of geologists, have you? smile.gif


Hehe. Well I can say that Alexander Bazilevsky or Jim Head would know better. I could put some sort of "cape does not allow wearer to fly" warning on my picture, I suppose. :-)

Posted by: Myran Sep 12 2006, 05:36 PM

You're in the http://www.space.com/scienceastronomy/060911_venus_images.html mr DonPMitchell. biggrin.gif

Posted by: Tayfun Öner Sep 12 2006, 06:21 PM

A quicktime VR would be nice.

Posted by: DonPMitchell Sep 13 2006, 02:53 AM

QUOTE (Tayfun Öner @ Sep 12 2006, 11:21 AM) *
A quicktime VR would be nice.


That's an interesting idea. I'll have to look into how to generate an image for QVR. I've used it (and its inventors are friends of mine, in fact), but I've never tried to generate content for it. Does the standard Quicktime plug-in everyone has show QVR images?

Posted by: JRehling Sep 13 2006, 02:57 AM

QUOTE (Tayfun Öner @ Sep 12 2006, 11:21 AM) *
A quicktime VR would be nice.



Venusian Reality?
laugh.gif

Might be fun except for the screaming and combusting.

ohmy.gif

Posted by: DonPMitchell Sep 13 2006, 03:45 AM

QUOTE (JRehling @ Sep 12 2006, 07:57 PM) *
Might be fun except for the screaming and combusting.


The temperature on Venus is approximately the same as an oven in self-cleaning mode. But the dense high-pressure CO2 atmosphere would greatly increase heat conduction, and super-critical CO2 behaves like a non-polar solvent. It's not a highly oxydizing atmosphere, so there would not be flaming combustion. Someone stepping out in shirt sleeves would be french-fried in mid air and eventually reduced to a char coal figure.

So, important safety tip.

Posted by: lyford Sep 13 2006, 06:34 AM

QUOTE (DonPMitchell @ Sep 12 2006, 07:53 PM) *
Does the standard Quicktime plug-in everyone has show QVR images?

Yes, http://www.apple.com/quicktime/technologies/qtvr/

Posted by: AndyG Sep 13 2006, 09:43 AM

QUOTE (JRehling @ Sep 13 2006, 03:57 AM) *
Venusian Reality?
laugh.gif

Might be fun except for the screaming and combusting.

ohmy.gif

The moment 90 atmospheres of furnace-hot CO2 starts to pour down your throat, I would imagine that screaming's not really going to happen. ohmy.gif biggrin.gif

But it's interesting that the view now feels so "normal". It could almost be an Icelandic image, or perhaps the top of a Scottish munro on an overcast day - walk over there and look down into a lochan. Maybe surprise a grouse behind that rock - the real Venusian environment doesn't seem to come across in this picture much if at all, whereas, in the originally portrayed slices, there was somehow a sense of a truly alien and hellish world, snapped in a few precious minutes between landing and melting.

For me, that makes it such a remarkable picture. Don's created our sister planet from scraps, and given us a familiarity that I certainly haven't had before. And I suppose that means we can now wonder - especially on the back of the MERs - about exploration. What lies over that edge, what vistas would greet us?

Andy

Posted by: hendric Sep 13 2006, 10:06 PM

AndyG

Here you go. smile.gif



Posted by: AndyG Sep 14 2006, 08:55 AM

QUOTE (hendric @ Sep 13 2006, 11:06 PM) *
AndyG

Here you go. smile.gif

Toastie! Thanks - that's more like it. Now if only it had had a http://personal.strath.ac.uk/a.goddard/venus.swf on it!

Andy

Posted by: ngunn Sep 14 2006, 10:51 AM

QUOTE (hendric @ Sep 13 2006, 11:06 PM) *
AndyG

Here you go. smile.gif


That's just brilliant, though I would expect a more orangey-brown colour for the sky and the distant hazy hills.

Posted by: DonPMitchell Sep 14 2006, 03:28 PM

QUOTE (hendric @ Sep 13 2006, 03:06 PM) *
AndyG

Here you go. smile.gif




I'm not sure I understand. What is the coloration for?

Posted by: hendric Sep 14 2006, 04:38 PM

AndyG was complaining that the "Real Venusian Environment" didn't come through, so I added a little bit of red to the picture to give it that "this is hot as an oven" look to it.

Posted by: DonPMitchell Sep 14 2006, 08:57 PM

QUOTE (hendric @ Sep 14 2006, 09:38 AM) *
AndyG was complaining that the "Real Venusian Environment" didn't come through, so I added a little bit of red to the picture to give it that "this is hot as an oven" look to it.


Ah! :-)

Of course the sky of Venus is actually bright orange. Everything is bathed in orange light, from a uniform hemispherical source. The cloud layer, far above, is not visible from the surface. Strong rayleigh scattering causes the terrain at a distance to be lost in a greenish-yellow haze that eventually merges with the orange color of the sky.

At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.

Colors from the Venera probes have never been rigorously calibrated. First of all, the radiometric response of the camera that was used before is incorrect. The spectral response of the color filtes is known, but not the relative gain correction. I have talked with Gektin about this (the camera designer), and he is searching for some data that will permit absolute calibration of the color. Namely, the spectrum of a colored calibration lamp, which was imaged during the video retrace interval.

The Russians knew what to do in theory. They realized you have to solve an integral equation to recover color from the spectral responses of sensors. Bravo for them, because I don't think any American space photos have ever been processed with that sophistication. But having written that in their paper, the Russians were unable to perform the calibration, because they lacked the necessary computers.

Posted by: ljk4-1 Sep 15 2006, 01:33 AM

QUOTE (DonPMitchell @ Sep 14 2006, 04:57 PM) *
At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.


I recall that all the drop probes from the Pioneer Venus Multiprobe mission reported
an increase in infrared glow before those sensors were overwhelmed. Any ideas on
what it might have been?

Posted by: ngunn Sep 15 2006, 08:45 AM

QUOTE (DonPMitchell @ Sep 14 2006, 09:57 PM) *
Ah! :-)

Of course the sky of Venus is actually bright orange. Everything is bathed in orange light, from a uniform hemispherical source. The cloud layer, far above, is not visible from the surface. Strong rayleigh scattering causes the terrain at a distance to be lost in a greenish-yellow haze that eventually merges with the orange color of the sky.

At night, the ground at low altitudes might glow faintly red from the heat, but it is just barely hot enough for that. I'm not sure if you could see it or not.


You have done so much work already to make the place look 'real' and obviously have your own mental picture of the true colouration. Why not share it with us? - perhaps day and night versions, assuming the ground glow is just visible?

Posted by: tty Sep 15 2006, 10:59 AM

QUOTE (DonPMitchell @ Sep 14 2006, 10:57 PM) *
The Russians knew what to do in theory. They realized you have to solve an integral equation to recover color from the spectral responses of sensors. Bravo for them, because I don't think any American space photos have ever been processed with that sophistication. But having written that in their paper, the Russians were unable to perform the calibration, because they lacked the necessary computers.



How very typical both of Russia and the US. As somebody said "as long as it can bew done with paper and pencil the russians are unbeatable".

tty

Posted by: vikingmars Sep 24 2010, 08:39 AM

huh.gif A new work on the Venera 9 - 14 images was presented 2 days ago by well known Venus scientist Dr Ksanfomality at the European Planetary Science Congress 2010:
http://meetingorganizer.copernicus.org/EPSC2010/EPSC2010-273.pdf
Unfortunately, no more details yet...
BUT, having myself analysed all the Venera data available, I don't think there is much more to be seen : all features on the horizons were enhanced and the Venusian sky shown already in this UMSF Forum topic.
_______________________________

[quote from the abstract with no images published] :
"In 1970-80 the VENERA 9, 10, 13 and14 probes imaged the surface of Venus at landing
sites. These TV photos have been published by many scientific editions, either original or
processed. Since the visits of the pioneering VENERA landers, there have been steady
efforts to achieve a better processing of the original images for following analysis. This
paper is devoted to the description of few segments of re-processed images at their right
and left hand sides, demonstrating features not noticed earlier (or ignored due to their
distortion). Using this re-processing, interesting images that included both horizon and
sky of Venus were produced. In the new images next mount chains or valley slopes
appeared at the horizon line
."

Posted by: JohnVV Sep 24 2010, 08:26 PM

this is an old thread . has the color issue been better solved since '06
As i recall , when i did my map and colorized the radar data , there were some images redone to get the color strip on the lander "closer" to there colors .
But did not take into account the effects from the pressure . and that the rocks would most likely have a slight bluish tint ( if they were on earth)
In the end I gave up and just used an artistic color
[attachment=22593:venus_VT...an_Vliet.jpg]

Posted by: sariondil Oct 2 2010, 12:37 PM

A collection of surface panoramas: 180° for Venera 9 and 10, 360° for Venera 13 and 14. Reprojections are according to various suggestions on this forum. Horizon topography is probably not real, but due to inaccuracies of the reprojections (which are not strictly geometric anyway).


 

Posted by: Phil Stooke Oct 6 2010, 06:06 PM

Nice job, Sariodil. I'm not sure I agree with your connections between features near the horizon for Venera 13, but it looks good anyway. I have often thought of trying to map these landing sites, so just playing with your images I came up with these for Veneras 13 and 14. Very preliminary, but it gives an idea of what might be done eventually. The orientations of these images (where north is, in other words) is unknown.

Phil




Posted by: Explorer1 Oct 6 2010, 07:35 PM

All these re-projections and reprocessing you've accomplished here just whets my appetite for new missions. The Venusian surface has been neglected for far too long...

Posted by: sariondil Oct 8 2010, 07:44 PM

I´m not sure about the Venera 13 horizon either. When the horizon in the Camera I image came out concave in the reprojection, I thought it could be a valley floor at a lower elevation than the hills in the adjoining part of the Camera II image. On second thought, however, smooth concave valley floors are probably not what you would expect on a planet with so little erosion.
But if erosion has no part in shaping the surface, could the gaps in the hills on the horizon be the surface expression of faults? If so, one could align them with the fault azimuths on Magellan images of the landing site to narrow down the possible orientation of the panorama.

Posted by: Phil Stooke Oct 8 2010, 08:46 PM

Good suggestion, but the areas covered by these reprojected images would span at most a few tens of pixels in Magellan images, and at locations in the images uncertain by many tens of kilometers, so it is very unlikely that we could do something like that.

Phil

Posted by: vikingmars Oct 9 2010, 07:00 PM

QUOTE (sariondil @ Oct 2 2010, 02:37 PM) *
A collection of surface panoramas: 180° for Venera 9 and 10, 360° for Venera 13 and 14. Reprojections are according to various suggestions on this forum. Horizon topography is probably not real, but due to inaccuracies of the reprojections (which are not strictly geometric anyway).

Thanks for your contribution. You did an interesting work.
The horizon of Venera 9 should be adjusted because the lander was sitting on a slope with a 20° tilt...
smile.gif

Posted by: 4th rock from the sun Oct 10 2010, 12:57 AM

It's not easy to extrapolate much from the Venera images. I'm yet to see a good geometrical correction of all the distortions.

Those "U" shaped strips are approximations, and looking at them I always have the feeling that the spacecraft is on lower ground relating to the horizon. The imaging system is similar to that of Viking, but the scanning is made at an angle in relation to the horizon.
The Venera cameras were about 2m above the surface but, as you move from the center to the edges towards the horizon, the image looks like they were taken with a lower point of view (more like Pathfinder).
All of this makes the horizon interpretation much harder. What looks like a slope might be an horizontal feature...

Posted by: Hungry4info Jul 21 2014, 03:22 AM

Ted Stryk has given the Venera 9 and 10 images a bit of a makeover.
http://planetimages.blogspot.com/2014/07/standing-on-venus-in-1975.html

Posted by: Explorer1 Jul 21 2014, 03:31 AM

Good catch! Why did I never notice the hills at Venera 9....

Posted by: 4th rock from the sun Jul 21 2014, 09:03 AM

Interesting results with those horizon features. laugh.gif
My only fear is that the results look too good. Easy to mistake the generated images for the actual ones...
Other than that, I still see some geometric distortion in the vertical axis. But I know from self experience that this is a difficult dataset.

Posted by: tedstryk Jul 21 2014, 04:06 PM

QUOTE (4th rock from the sun @ Jul 21 2014, 09:03 AM) *
Interesting results with those horizon features. laugh.gif
My only fear is that the results look too good. Easy to mistake the generated images for the actual ones...
Other than that, I still see some geometric distortion in the vertical axis. But I know from self experience that this is a difficult dataset.

The problem is that there are less that 50,000 pixels showing the surface, and so I used somewhat distorted repeats to fill gaps in the case of Venera 9. The hills to the left can be seen at the edge of the original panorama. Many versions I've seen have the horizons so overexposed that the hills are lost. The middle hill is of course a creation created from cloned bits of the stuff on either corner...here was my thinking...there are relatively big hills on the left, and the ground is choppy on the right-hand horizon. Venera-9 is itself on a slope. So there is little chance that the horizon is flat between the two corners of the panorama. It took dozens of times going back to the drawing board before I got something that looked half-way decent. Venera 10 was much easier.
I was also trying to project it to look as though one is looking from one point rather than moving along the scene is the camera scanned...that improves some things, but creates other geometric issues.
As I said, everything is from cloned portions of the actual image data. Nothing is drawn outright. That might be an interesting experiment.

Posted by: 4th rock from the sun Jul 22 2014, 10:20 AM

The idea of providing a "synthetic" scene is interesting.

You could to the same using elements from earth photos. As long as rock size, distribution, overall shape and composition are the same, it's a valid experiment. I'd go for that and totally skip the original imagery.

Posted by: tedstryk Mar 5 2015, 05:34 PM

Venera 14 landed 33 years ago today. I wrote a new blog entry about it. http://planetimages.blogspot.com/2015/03/venus-from-33-years-ago-and-why-we-need.html

Posted by: JRehling Mar 5 2015, 05:43 PM

Very nice, Ted! Putting the images where they can be compared is very evocative. And yes, it's tantalizing to think of how much of Venus we haven't seen. One ground-buzzing airplane taking hi-definition video as it zoomed along a long ground swath could increase our ground-level imagery by a few orders of magnitude. If only the will were there...

Posted by: tedstryk Mar 5 2015, 05:54 PM

QUOTE (JRehling @ Mar 5 2015, 05:43 PM) *
Very nice, Ted! Putting the images where they can be compared is very evocative. And yes, it's tantalizing to think of how much of Venus we haven't seen. One ground-buzzing airplane taking hi-definition video as it zoomed along a long ground swath could increase our ground-level imagery by a few orders of magnitude. If only the will were there...


Thanks. I love the idea of a balloon that rises and falls with the day so that it touches down in multiple locations. I've added a second interpretation of the color in the combined image.

Posted by: Julius Mar 5 2015, 07:32 PM

It's time to go back and explore!

Posted by: rlorenz Oct 25 2015, 02:02 PM

My short paper just out in Icarus on the observed probability distribution of Venus surface winds (useful for lander design, as well as evaluation of aeolian transport) . It is remarkable that on only two ~hour long occasions when aeolian transport of regolith could possibly have been observed (by Venera landers), it was seen on one. Typically one has to wait months to see something happen on Earth or Mars - Venusian sediment is therefore probably always on the move, something that might be observable with radar interferometry, as well as lander observations...
(link to free pdf valid for 50 days)



http://authors.elsevier.com/a/1RvsN4L-YESvT

Posted by: nprev Oct 25 2015, 06:09 PM

Thanks for sharing this with us, Ralph. In your estimation, were the Veneras on the high or low side of optimum landing configuration (if that makes sense) given your analysis?

Posted by: rlorenz Nov 3 2015, 02:45 PM

QUOTE (nprev @ Oct 25 2015, 01:09 PM) *
In your estimation, were the Veneras on the high or low side of optimum landing configuration (if that makes sense) given your analysis?


None of them fell over, so the design can be claimed to be robust. But the question of optimality is meaningless without a stated success criterion (i.e. given an [unknown]
surface slope distribution and given an [unknown, but kindof handwavy-estimated here] wind distribution, and given a requirement for e.g. 99% success THEN a certain
design can be considered optimal)

The fundamental point is that any planetary landing entails uncertainty (qv Philae) and thus no finite-cost design can offer 100% reliability. Thus rational design and
evaluation entails the statement of an acceptable degree of risk. Where terrain (or meteorological) factors introduce an entirely stochastic element to the landing
dynamics, an optimal mission solution may be to build two 90% landers to achieve an overall 99% chance of safe landing.

Posted by: nprev Nov 4 2015, 02:29 AM

Understood. My question was quite poorly constrained. smile.gif Thanks!

Posted by: hendric Nov 4 2015, 03:40 PM

Ralph, that report sounds promising for powering a long-duration lander with wind power. 90 times Earth's atmospheric density, would mean the .4 m/s wind is equal to ~3.8m/s, close to cut-in speed for a decent wind turbine. And I would assume windier times and locations are possible? Would it be a good assumption that windspeeds on Venus' surface don't change quickly, since the rotation is so slow?

I guess a space-based instrument won't be able to monitor windspeeds - on Earth the __Scat family of satellites use ocean roughness as a proxy for surface windspeed. I propose a mission to drop a load of neutrally buoyant reflective strips onto Venus along with a radar platform to monitor their distribution. smile.gif

Posted by: tanjent Nov 5 2015, 05:34 AM

QUOTE (rlorenz @ Nov 3 2015, 10:45 PM) *
Where terrain (or meteorological) factors introduce an entirely stochastic element to the landing
dynamics, an optimal mission solution may be to build two 90% landers to achieve an overall 99% chance of safe landing.


If the (total) cost of an estimated p=99% mission success is more than double that of a p=90% mission, that formula presents an excellent argument for building and launching duplicate missions, as in the case of Viking or Voyager or MER. Because 81% of the time, you may then hope to realize not one but two successes. (In each case, the second success might be considered partially redundant, but only partially.)

Posted by: mcaplinger Nov 5 2015, 05:52 AM

Unfortunately, here in reality the relationship between cost and probability of mission success is not quantifiable with any precision. I'm not even sure that spending more money increases probability of success in all cases.

Posted by: JRehling Nov 5 2015, 05:42 PM

QUOTE (mcaplinger @ Nov 4 2015, 10:52 PM) *
Unfortunately, here in reality the relationship between cost and probability of mission success is not quantifiable with any precision.


Agreed. Many in-situ hazards are of unknown incidence, and knowledge of their incidence is exactly the kind of knowledge that the mission is meant to acquire, so there's a Catch-22 there in principle.

Not only Huygens but also an early Venera lander were designed to float. This was overly cautious in both cases, as it turned out. The designers could have thought and spent all they wanted, but ultimately, some exploration had to be done to ascertain whether or not flotation was required. They could have spent a trillion dollars on it and not gotten a better answer than they did by actually flying a mission and seeing what the surfaces of Venus and Titan are like.

Then again, the next Venus lander may unluckily sink into a pond of molten tin. It's hard to prove otherwise until we've explored Venus thoroughly.

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