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Unmanned Spaceflight.com _ Venus _ Venera-13, Venera-14 Lander Images
Posted by: DonPMitchell May 5 2006, 07:40 PM
Here are images I generated from the 9-bit Venera-13 and Venera-14 data. Most of the work was spent combining three or four transmissions from the spacecraft, each with an independent set of digital noise. In some cases, scrambled regions of images were restored by recalculating the 10th parity bit, and shifting the bit stream. In particular, I resurrected a new section of the image on Venera-14 Camera II on the left side. I managed to distill out one very high quality copy of the full transmission from each of the four cameras.
Next, there is the problem of linearizing the camera response. The camera response curves published in Cosmic Research are wrong, or at least they do not extend into the darker range where a lot of the actual Venus imagery lies. You can prove they are wrong from the calibration wedges, viewed through the four different filters. Correct generation of true log response would result in wedge profiles that are exactly offset from one another. Some recent work on camera self-calibration in the computer-vision community points the way to reconstructing response curves, and when applied to the Venera images, the result is very pleasing. Round objects, like the elbow joint of the penetrometer, look round, not flat, details in shadows appears out of the blackness of the original Russian images, and some additional hills on the horizon appear out of the formerly white sky.
The full transmission consisted of several passes of the camera scanner, back and forth, across the scene. These four panoramas are combinations of up to five black-and-white images (clear filter), and a number of red, green, and blue-filter images. In Lab color coordinates, I extracted the ab channels from the red/green/blue images, and added them to the much higher quality B/W images. You can see that when making scans through the clear filter, the camera covered a wider area, the uncolored regions are just where the RGB data did not exist. Most of the blue images are black, due to a sudden drop-off in the camera response. There are probably a few areas near the bright horizon where the real RGB ratio can be extracted...a project for someone someday.
I've been too busy with my book and my company in Seattle to completely finish what I wanted to do. The color is still not correct on any Venera surface images. But the color filters in the camera were balanced with gray filters to be somewhat correct. I am awaiting one last key piece of data -- the spectral response of a color filter that was in front of the calibration wedge. With that in hand, an absolute color calibration would be possible.
Venear-13, Camera I (short program):
Venera-13, Camera II (long program):
Venera-14, Camera I:
Venera-14, Camera II:
Posted by: ljk4-1 May 5 2006, 07:54 PM
FYI - There is also a thread on reconstructing Venera lander images here:
http://www.unmannedspaceflight.com/index.php?s=&showtopic=1410&view=findpost&p=20445
Posted by: DonPMitchell May 5 2006, 07:59 PM
http://www.unmannedspaceflight.com/index.php?s=&showtopic=1410&view=findpost&p=20445
Looks like his image was reconstructed from a set of Russian processed images. Not the raw data actually.
Posted by: 4th rock from the sun May 5 2006, 08:03 PM
Very nice work!!! Thank you for the time you took on these images and for sharing them.
Any plans to make original CRGB data avaliable? Perhaps some super-resolution images could be created that way ;-)
Posted by: DonPMitchell May 5 2006, 09:15 PM
Ah, now I learn how to attach a picture with a thumbnail.
[attachment=5455:attachment]
Anyway, here is an example of Venera-13 Camera II, as the Russians processed it. These are their composites of multiple red, green, blue and clear-filter images. It has been linearized, but not correctly.
The actual raw transmission looks like this:
[attachment=5456:attachment]
Is was sent as a 10-bit per pixel image, with one bit being parity. It's (sort-of) log of brightness. On the top (er, left), you see a calibration ramp which is scanned during the blanking interval, while the scanner is returning.
The camera is a photo multiplier tube, some fancy optics and a mechanical scanner. Don't laugh, a PMT is the absolute best light measuring device known to man, so the image quality was amazing. The mirror sat inside a 1-centimeter thick cylindrical quartz window, and inside the camera was a special lens that inverted the effect of the refraction of the window. (Russians know their optics!). Most of the pictures you see are horrible scans made off a copy of Pravda or something.
So the transmission from the lander was a long series of repeating scans like this, back and forth, with color and clear filters dropping into place. This was recorded digitally on the main spacecraft, and relayed and replayed back to Earth multiple times. From the lander to the main craft, the transmission was PCM on a phase modulated meter-band carrier. From spacecraft to Earth was sent the same, but with convolution coding. On Venera-9, the situation was similar except the orbiter transmitted the single to Earth by an N-ary PPM signal.
More than you wanted to know, right?
Posted by: lyford May 5 2006, 09:58 PM
Hi Don - As someone who has lurked around your Soviet exploration of Venus website, it's great to see you here!
Posted by: Decepticon May 5 2006, 10:51 PM
WOW!
Great work, keepers for sure. 
Posted by: RNeuhaus May 5 2006, 11:45 PM
Thanks Don to share with us your posting's pictures. Up to now, these pictures are very apreciated since these are most unique. After looking the Venusian panorama, it looks like a very cloudy day and it seems that under the lower of clouds, there is a far visibility view and the land is relatively plain, not big boulders, stones unless these rocks are flat and with layers.
I have the curiosity whereabouts how many the Venera's sondas have taken pictures on Venusian surface? It seems like no more than ten fingers? 
Rodolfo
Posted by: DonPMitchell May 6 2006, 02:59 AM
I have the curiosity whereabouts how many the Venera's sondas have taken pictures on Venusian surface? It seems like no more than ten fingers?
Rodolfo
Successful Veneras in a nutshell:
Venera-3: impact with no signal
Venera-4: analyzed atmosphere, batteries ran out
Venera-5: more accurate analysis, crushed
Venera-6: ditto, crushed
Venera-7: first landing, returned surface temperature
Venera-8: landed, photometer discovered cloud depth
Venera-9: landed, first pictures, nephelometer profiles
Venera-10: landed, orbited, pictures
Venera-11: landed, orbited, detailed spectra, lightning detected
Venera-12: landed, same as V-11
Venera-13: landed, color pictures, rock analysis
Venera-14: landed, color pictures, rock analysis
Venera-15: orbited, radar imaging, IR Fourier Spectrometry
Venera-16: orbited, radar imaging
Vega-1: landed, rock analysis, cloud analysis
Vega-2: landed, rock and cloud analysis
I'm leaving out a lot of stuff, there were magnetometers, IR and UV spectrometers, polarimeters, mass spectrometers, gas chromatography, etc, etc.
And yes, 10 landings.
Posted by: BruceMoomaw May 6 2006, 03:21 AM
Oh, yes; facsimile cameras, simple though they are, can turn out very high-quality photos. Don't forget that the Viking Landers also used them.
Regaring the list of "successful" Venera landers, however: there are several decided judgment calls. Only one of Venera 7's two onboard instruments -- its temperature sensor -- worked; its pressure sensor failed. Venera 11 and 12 -- which were the first attempt at the mission later successfully carried out by Veneras 13 and 14 -- had both their sample drills and the ejectable covers on their cameras fail; only their atmospheric instruments worked. (One Russian writer reports that this was due to excessive haste and low funding of the landers' development, and that this -- along with the cancellation of Lunokhod-3 and the long delay in the launch of Luna-24 after the failure of #23 -- was all due to the fact that the Kremlin was then trying to steal a march on the US by developing a Mars sample-return mission, which turned out to be a hopeless endeavor.) And the Vega-1 lander's sample drill triggered prematurely while the probe was still descending, preventing it from making any X-ray spectral analysis -- although its gamma-ray spectrometer and atmospheric instruments worked and it properly released its cloud-layer balloon.
So, of the 10 Soviet Venus landers that survived their landings, about three can still arguably be called only "partial successes" -- and only four returned photos. Still, that's certainly a better record than their Mars missions... And it remains a fact that Venus landings and automatic dockings in Earth orbit are the two outer-space areas in which the US still hasn't matched Russia.
Posted by: RNeuhaus May 6 2006, 03:22 AM
Don, I am sorry that I haven't clarified well enough my previous question. I wanted to know about how many pictures has all Russian sondas have taken? I seems that are as few as ten pictures in the total for all spacecrafts. Aren't it? 
Rodolfo
Posted by: DonPMitchell May 6 2006, 08:54 AM
Rodolfo
Missions with cameras:
Luna-3
Zond-3
Luna-9 lander
Luna-13 lander
Lunokhod-1
Luna-20 lander
Lunokhod-2
Mars-3
Mars-4
Mars-5
Venera-9 lander
Venera-9 orbiter
Venera-10 lander
Venera-13 lander
Venera-14 lander
Vega-1 (Halley pictures)
Vega-2
Phobos-2 (CCD and thermoscan)
I didn't count the Mars-3 lander, which just sent back a few scanlines of noise. And of course Earth-orbiting spacecrafts with cameras are hundreds, mostly spy satellites and resource satellites.
Posted by: tasp May 6 2006, 02:14 PM
Really appreciate the newly processed pictures!
Additionally, it is my understanding the Vega 1 and 2 landers had their cameras removed as the Halley intercept trajectory required a night time landing.
My question:
Some of the early landers had lights on them for their cameras (the lights weren't needed and were deleted on subsequent landers. Why, oh why, didn't they put lights on Vega 1 and 2 instead of removing the cameras?!?!?!?!?!?!?
Seems like an opprotunity to get some nice pictures of the surface with a light source tested and calibrated on earth would generate the most accurate color pictures possible. That would be a 'good thing', right?
I am probably missing something, but I am really wondering about this.
Also, the list of missionsis really helpful, keep in mind though, there are a very large number of launch failures not mentioned in the Soviet era literature.
Posted by: DonPMitchell May 6 2006, 02:46 PM
That's an interesting question. And one actual surviving Russians can answer, so I will ask them!
Posted by: tedstryk May 6 2006, 03:08 PM
I asked Sasha Basilevsky years ago (well, actually, I didn't ask him, I asked someone at Brown, and they forwarded my question to him and I got his reply). Basically, when the mission was designed, it was originally the next Venera mission, which morphed into the Ve-Ga (short for Venus-Halley - the Russians have no H in their alphabet). It was modified to fly by Venus and on to Halley. This was relatively late in the game, and the trajectory change left the landers no choice but to land on the night side. Adding lights would have been too much of a design change for the already built landers. It also left the balloons without a relay, which really damaged the science that they obtained (with direct to earth transmission, and with the help of the DSN, they managed to trickle back data at 4 bits/second which was so compressed, using very crude techniques by today's standards, that interpreting a lot of it is difficult, to say the least).
Posted by: DonPMitchell May 6 2006, 04:56 PM
I just talked to Sasha, and he suggested that weight was an issue too. Vega was loaded down with experiments and fuel. It had more instruments for the Halley encounter than the other two missions combined, it had the balloon aerostats, etc.
Speaking from my own research, Vega was really focused on answering a lot of open questions about the clouds of Venus. One of the camera positions was occupied by an ultraviolet spectrometer, and the landing ring was completely covered with devices, mostly for the analysis of cloud particles.
Direct broadcast from Venus is pretty slow. That was a probelm with the Pioneer Venus landers too. Venera-11 and 12 sent about 100 times as much data as the four Pioneer landing probes, because they had to do something similar to the aerostats. Not sure why they didn't try to use the Pioneer Venus Orbiter to relay data.
Posted by: tedstryk May 6 2006, 05:24 PM
Speaking from my own research, Vega was really focused on answering a lot of open questions about the clouds of Venus. One of the camera positions was occupied by an ultraviolet spectrometer, and the landing ring was completely covered with devices, mostly for the analysis of cloud particles.
Direct broadcast from Venus is pretty slow. That was a probelm with the Pioneer Venus landers too. Venera-11 and 12 sent about 100 times as much data as the four Pioneer landing probes, because they had to do something similar to the aerostats. Not sure why they didn't try to use the Pioneer Venus Orbiter to relay data.
It probably wasn't capable. Remember, it was the Bus that relayed the multiprobe data back, not PVO.
Posted by: mcaplinger May 6 2006, 05:53 PM
Recall that the PV orbiter and probes/bus were separately launched; you wouldn't want to make one dependent on the other if you could avoid it.
Posted by: ljk4-1 May 6 2006, 07:23 PM
And in the mid-1980s, the US and USSR were going through another Cold War freeze.
They weren't very big on cooperating, though one US professor did get his dust
analyzer on the Vegas, the only US science instrument on a space probe aimed
for Comet Halley after an actual mission was canned.
Venera-3: impact with no signal
Venera-4: analyzed atmosphere, batteries ran out
I thought Venera 3 stopped transmitting just days before reaching Venus,
just like its counterpart Venera 2 did. So other than being the first craft
to impact on Venus, how could it be called a success?
Even more interesting, I thought Venera 4 was crushed by the planet's
dense atmosphere before it could land. Carl Sagan relays a very humorous
story in his 1973 book, The Cosmic Connection, regarding how Soviet
scientists tried to defend their claim that Venera 4 did reach the planet's
surface still functioning.
So are you now saying Venera 4 actually lost battery power - and therefore
communications with Earth - before being crushed? At what altitude?
Posted by: DonPMitchell May 6 2006, 09:22 PM
They weren't very big on cooperating, though one US professor did get his dust
analyzer on the Vegas, the only US science instrument on a space probe aimed
for Comet Halley after an actual mission was canned.
I thought Venera 3 stopped transmitting just days before reaching Venus,
just like its counterpart Venera 2 did. So other than being the first craft
to impact on Venus, how could it be called a success?
Even more interesting, I thought Venera 4 was crushed by the planet's
dense atmosphere before it could land. Carl Sagan relays a very humorous
story in his 1973 book, The Cosmic Connection, regarding how Soviet
scientists tried to defend their claim that Venera 4 did reach the planet's
surface still functioning.
So are you now saying Venera 4 actually lost battery power - and therefore
communications with Earth - before being crushed? At what altitude?
Oops, Venera-3 wasn't really a success, except for its deep-space science. Well, it did hit its target though. :-)
Sagan believed Venera-4 ran out of battery power. It was rated for 100 minutes, and it transmitted for 93 minutes. Keep in mind, the atmosphere of Venus was much more dense than almost anyone expected. It doesn't seem to have reached the depth that it was designed for. The Russians never admitted this, but on Venera-5 and 6, the parachutes were made much smaller, and they went deeper. No one can be sure about this though.
Yes, I've read what Sagan and Kuz'min have had to say about this. I've been trying to gently coax Kuz'min into telling me more about that event. It was not actually unreasonable to believe Venera-4 landed, given what was expected about Venus. Radio altimeters have something called "ambiguity", so it was only really the Mariner-5 occultation data that let people figure out later that it stopped transmitting at 22 km.
With regard to mission failures, most were the result of Block-L failure -- lots of interesting planetary probes were just left in orbit. Escape stages are difficult. The Russians just started using Block-L right from the start. The Americans just waited (and waited...and waited...) for the Centaur stage to work right. It's not obvious the Russians did the wrong thing there. They managed to launch a number of big complex probes with Block-L, while the Americans were very limited by what they could do with Agena.
Posted by: DonPMitchell May 6 2006, 09:32 PM
Getting back to the original topic for a minute, here is the true-color calibration that Brown Univerisity did some years ago:
[attachment=5473:attachment]
It's based on information about the sky spectrum from the lander's spectrometer, and from information about the color of the ground, particularly from the Venera-9 lander (from its photometer, not its camera).
The real solution to the color problem is yet to be done I think. Futhermore, given the known spectral response of the color camera filters, the right way to calculate color is by solving an integral equation, the so-called inverse method. Nobody ever does that, but the original Russian papers at least mention it (Those Russians know their math!).
Posted by: tedstryk May 6 2006, 10:30 PM
I do think the general appearance is roughly accurate in the top version - blue is so weak on the surface. The color under more earthlike lighting conditions is the real question.
Posted by: BruceMoomaw May 7 2006, 01:03 AM
The Soviets were actually quite explicit on the fates of Veneras 4 through 6 -- after they finally got through grudgingly admitting that Venera 4's radar altimeter was incorrectly calibrated and that Mariner 5's S-band occultation measurement of Venus' real air pressure and temperature was correct. Venera 4's hull was only designed to withstand 20 atm of pressure. In the case of Venera 5 and 6, which were already scheduled for launch in 1969 (probably on the assumption that Venera 4 might be yet another failure) at the time that they finally accepted that Mariner 5 was corrrect, they hastily thickened the hulls a little to withstand 27 atm -- which they both did. Then they promptly designed Venera 7 to settle the question of surface atmospheric conditions once and for all by thickening its hull to withstand fully 150 atm, and equipping it only with temperature and pressure sensors (like the probe that Avco had proposed for Mariner 5, in fact). The pressure sensor failed, but the combination of the temperature measurments and the time it took for Venera 7 to land allowed an indirect estimate of pressure as well, fully confrming Mariner 5's results.
So then the Soviets, certain at last, moved on to designing Venera 8 -- a probe thick-hulled enough to withstand genuine Venusian surface conditions, but as well-instrumented as the earlier Veneras (and in fact better, given its gamma-ray spectrometer and its daytime landing with a light-level photometer). Given the fact, however, that they could have built and flown this craft in 1970, their insistence on flying Venera 7 first indicates either bizarre conservatism on the the part of the Soviet program, or the fact that they didn't have enough money to build and fly Venera 8 that early.
As for the true color of the Venusian surface, Carle Pieters did an excellent article all the way back in the Dec. 12, 1986 "Science" compensating for the orange sunlight to confirm that Venus' surface is actually an inspiring shade of flat gray.
Posted by: DonPMitchell May 7 2006, 02:33 AM
So then the Soviets, certain at last, moved on to designing Venera 8 -- a probe thick-hulled enough to withstand genuine Venusian surface conditions, but as well-instrumented as the earlier Veneras (and in fact better, given its gamma-ray spectrometer and its daytime landing with a light-level photometer). Given the fact, however, that they could have built and flown this craft in 1970, their insistence on flying Venera 7 first indicates either bizarre conservatism on the the part of the Soviet program, or the fact that they didn't have enough money to build and fly Venera 8 that early.
As for the true color of the Venusian surface, Carle Pieters did an excellent article all the way back in the Dec. 12, 1986 "Science" compensating for the orange sunlight to confirm that Venus' surface is actually an inspiring shade of flat gray.
The relationship between Venera-4 and Mariner-5 was far more complex than that. To interpret the data correctly, you needed to know several facts:
1. The refractive index of the atmosphere (Venera-4's gas analysis)
2. Accurate temperature and pressure readings (Venera-4)
3. An absolute measurement of radio refraction at a fixed distance from the planet's center (Mariner-5)
4. The radius of Venus' hard surface (Kuz'min and Clark's 1964 experiment)
The fact that Venus's atmosphere was almost pure CO2 (which is highly refractive), changed a lot of things. Kuz'min quickly recalculated the surface temperature from microwave spectra (upgrading it from 600 to 700 K), and he corrected the radar measurements of the hard-surface radius.
As for what happened to Venera-4, nobody knows. I think Sagan's theory is plausible, but certainly not the dramatic macho failure mode the Russians would prefer to announce.
I refer to Pieters work above, see the posting with the color and white-light corrected panoramas. Unfortunately, they used an incorrect camera response function. The result could be improved with additional information that exists now.
Posted by: Bob Shaw May 7 2006, 03:41 PM
Don:
Great images - it's a joy to see old data given new life!
Bob Shaw
Posted by: rogelio May 8 2006, 12:48 AM
In the upper left hand corner of DonPMitchell's Venera 13, Camera 1 (short program) photo, there appears to be the distant, blurred flank of a mountain or hill visible on the horizon... Is this an artifact or are we truly seeing a hill some distance away?
Posted by: DonPMitchell May 8 2006, 02:45 AM
Yes its a hill in the distance. They just blew out the pixels when they stretched the contrast, in the Russian versions. It's very clearly there in the raw data.
You also see some hills in the color-filter images, in the camera-II images, because the gain blew out the pixels in the clear-filter images.
Posted by: Rem31 May 8 2006, 05:38 PM
How will it really look when i am standing on the surface of Venus? Like grey or like a orange color.
Posted by: helvick May 8 2006, 05:50 PM
It might look orange for a while but if you could stay there for a while your eyes would adjust and you would begin to find the orange increasingly less noticable.
You can see a limited similar effect by wearing 3D anaglyph specs for an extended period of time and then taking them off. If you alternately close one eye and then the next everything will appear to be alternately blue\red tinged.
Posted by: ljk4-1 May 8 2006, 05:58 PM
You can see a limited similar effect by wearing 3D anaglyph specs for an extended period of time and then taking them off. If you alternately close one eye and then the next everything will appear to be alternately blue\red tinged.
Remember when they used to claim that the Venusian atmosphere
was so refracted that you could technically see all the way around
the planet and right to the back of your head (or whatever special
helmet was shielding it)?
http://www.cosmographica.com/gallery/portfolio/portfolio051/pages/096-%20Superrefraction%20.htm
Posted by: kwp May 8 2006, 06:23 PM
Until, of course, your eyes melt.
On a more serious note, I've never seen the Venera landing sites pinpointed on the Magellan-based map of Venus. Anyone have any pointers? Heck, for that matter how well is our knowledge of the landing locations constrained? (I don't think Phil-o-vision's gonna help us much this time.)
-Kevin
Posted by: helvick May 8 2006, 06:59 PM
...or your skin burns, lungs and sinuses collapse or the rest. What a human eye and brain would actually perceive on the surface of Venus is a decidedly unlikely question to be actually answered by a real human eye any time soon, if ever. It will certainly be the last proper surface humans will ever visit in person, assuming we ever get back into the habit of doing that.
Posted by: Rem31 May 8 2006, 07:13 PM
was so refracted that you could technically see all the way around
the planet and right to the back of your head (or whatever special
helmet was shielding it)?
http://www.cosmographica.com/gallery/portfolio/portfolio051/pages/096-%20Superrefraction%20.htm
Why is the refraction and the distortion of the Venus surface and atmosphere not visible in the venera images?
Posted by: helvick May 8 2006, 07:29 PM
Quoting Don from his second or third post:
I reckon it's likely that any additional refraction effects caused by the different refractive indices of the inner and outer atmospheres was included in that bit of optical wizardry.
Other than that the only distortion would have resulted from temperature gradients in the external atmosphere whichare highly unlikely to be significant given the fairly short range covered.
Posted by: Phil Stooke May 8 2006, 08:21 PM
Rem31 asked about the atmospheric distortion... that concept was grossly exaggerated before the Veneras landed. Now we know it doesn't really happen the way people used to suggest.
kwp asked: "On a more serious note, I've never seen the Venera landing sites pinpointed on the Magellan-based map of Venus. Anyone have any pointers? Heck, for that matter how well is our knowledge of the landing locations constrained? (I don't think Phil-o-vision's gonna help us much this time.)"
I didn't check but I expect they are marked on Ralph Aeschliman's nice map (Ralphaeschliman.com) (edit - no they are not but his maps are worth a look anyway). I'll try to find a source. I'm going to be mapping them myself in a year or two. The locations are only known to a degree or so (about 100 km)... I assume. What we have not been able to do, and never will with existing landers, is know the exact location on a specific pixel of a Magellan image. The only way we can hope to do that is with descent imaging. This is really important for any future landers, because it is crucial to know what geologic unit you are on. Our ability to interpret existing Venera data is limited because we don't know this now.
Phil
Posted by: JRehling May 8 2006, 08:30 PM
Rodolfo
If you mean surface pictures, two landers took 180-degree black and white panoramas; two other landers took 360-degree color (or partly color) panoramas. Due to the "economical" (and strange) scan concept, though, the panoramas do not show anywhere near 360 degrees of horizon, and concentrate more on the foreground.
Phil
The Sky and Telescope Venus globe shows all (Venera, Pioneer, Vega) of the landers' locations, to whatever accuracy. I have it on my desk!
I believe the exact content of the globe is here
http://photojournal.jpl.nasa.gov/catalog/PIA03167
but the thumbnail is too small to check, and the full version is too big for me to bother with right now.
Posted by: Bob Shaw May 8 2006, 10:22 PM
-Kevin
Kevin:
Don't let the humans know about *our* solid eyes! They are not yet fit to use that knowledge in a responsible fashion.
Bob Shaw
Posted by: DonPMitchell May 9 2006, 12:40 AM
Take a look at Abdrakhimov & Bazilevsky, The Geology of Venera and Vega Landing-Site Regions. Very nice paper.
The location of Venera-8 is known to within a radius of about 300 km, the later landers to within 150 km. The first impact, Venera-3, is known to within 800 km. Up through Venera-7, the Russians were aiming at the center of the visible face of Venus, so the landers could beam a tight signal straight up.
The Vega aerostats were tracked to very high accuracy, by differential interferometry. But they drifted around to the other side of the planet, and nobody knows when the balloons failed after that.
Basilevsky thinks Venera-9 landed on the side of a canyon, within the 150km disk, given the rocky terrain seen, and the steep incline (the probe was resting on a 20 degree incline, lucky to have remained upright!).
Posted by: DonPMitchell May 9 2006, 06:59 PM
Here are some perspective reprojections of the Venera images. The optico-mechanical camera returns an image in spherical projection. These are sectioned up and transformed into overlapping perspective views, which are then blended together in Photoshop CS2. Missing pieces of terrain are created by duplication and reversal. And of course, the left and right sides of the images are actually views of the terrain that are 180 degrees apart, so some artistic license taken here.
[attachment=5515:attachment] [attachment=5516:attachment]
Posted by: Rem31 May 9 2006, 07:12 PM
That are great images ,about of how it will look when you are standing on Venus. With 400+ degrees celsius of course and that is (less) funny. 
Posted by: DonPMitchell May 9 2006, 07:28 PM
Yep. Venus is slightly hotter than your kitchen oven when it is in "self cleaning" mode. So a person would be reduced to a fine white ash. Oh but maybe not in a reducing atmosphere -- you might just be carbonized into a charcoal statue of yourself.
Posted by: Bob Shaw May 9 2006, 08:05 PM
Don:
Do you have any feel for the distances to the distant parts of the Venera-13 image? And are those bits of the image 'real'? If so, that looks like it was indeed a lucky little lander!
Bob Shaw
Posted by: kwp May 9 2006, 08:06 PM
Fabulous! Despite having spent much time staring at your other (impressively) reprocessed Venera images this is the first time I can get my head around what the view might actually look like. In the interests of verisimilitude I'd love to see the same image with an overlay indicating which portions are "artistic license" rather than simple mathematical reprojections. (Or just lacking the missing pieces of terrain.) On a similar note, how much of the horizon is really captured in those little diagonal strips across the corners of the images?
-Kevin
Posted by: DonPMitchell May 9 2006, 08:12 PM
-Kevin
You can look at the original panoramas I posted earlier to see what all of the original horizon is. The rest is the same image copied or reversed.
The camera on the lander is only about 1 meter off the ground, so the features are smaller than you might think. Visibility is also quite limited in the thick atmosphere. The horizon is probably only hundreds of meters away.
Posted by: Phil Stooke May 9 2006, 09:16 PM
Great stuff, Don.
Phil
Posted by: RNeuhaus May 9 2006, 09:39 PM
It is like to see how the cake is cooked! in the oven
Rodolfo
Great images. Never seen before such oddies surfaces types. No much boulders, brokes stones, but just much laminated sedimentations of lavas?
Rodolfo
Posted by: Rem31 May 9 2006, 09:40 PM
How are the Veneras doing at this moment? Are they still intact or are the burned.
Posted by: DonPMitchell May 9 2006, 10:02 PM
At first, people thought they might be seeing sedimentary rock, but today it is believed the layering is volcanic ash and/or meteor-impact dust.
The Veneras are probably just sitting there today. They weren't made of anything that would melt or burn up, except some of the inside components. There doesn't seem to be much of any weathering on the surface.
Posted by: 4th rock from the sun May 9 2006, 10:19 PM
GREAT!!! This is a dream coming true for me... The surface of Venus in a "human vision" perspective!
Many thanks for sharing!
Posted by: SFJCody May 9 2006, 10:32 PM
These are great! Someone should do a nicely scaled comparison of Venus/Earth/Moon/Mars/Titan terrain slices now.
Posted by: BruceMoomaw May 9 2006, 11:52 PM
Yep; Basilevsky has pointed out that the gamma-ray densitometers on Veneras 9 and 10 and the penetrometer on #13 -- instruments that I would have been willing to swear would be scientifically useless -- all indicate that the "rocks" are all rather low-density and slightly softer than standard volcanic rock. (#14's penetrometer, in that famous stroke of bad luck, landed squarely on one of the ejected camera covers.) Both these measurements and their visual appearance indicates that what we're actually looking at is flat sheets of ash or dust, fused together by a sintering process which also apparently explains the virtually total absence of aeolian soil movement on Venus -- one of Magellan's most astonishing discoveries, since even Venus' sluggish 1 meter/second surface breeze, in that super-thick air, should have pushed soil grains along pretty efficiently. (The only dune fields it saw on Venus were located near large craters -- apparently surface material blown along by the blast of air from the impact.)
One theory, backed up by lab tests, is that the reactive trace gases in Venus' lower atmosphere -- at the planet's high surface temperature -- have caused small amounts of calcite and other carbonates in the soil grains to fuse them together, so that Venus' surface soil is "crunchy".
Posted by: 4th rock from the sun May 10 2006, 12:29 AM
This post left me thinking about the horizon details visible on the "new" reprocessed images. So I joined both V13 panoramas on the places were they overlap. This gives us some degrees of horizon on 2 opposite directions. The interesting thing is that there is continuity on the horizon features over the missing space.
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I've traced the 2 horizons visible on the images with diferent colors and it's interesting to see that the "distant" horizon is only present on the "bottom" of the image. With so little actual data it impossible to tell for sure, but my interpretation is that the terrain is lower towards the bottom right of the image, and higher towards the top.
I'll do the same with V14 and post the results when I have the time!
Posted by: Phil Stooke May 10 2006, 12:53 AM
This sort of landing site mapping is one of my goals in the next year or two. It's a bit tricky getting the geometry right. One other point of interest to cartographers: we don't know the orientation of the map.
Phil
Posted by: DonPMitchell May 10 2006, 01:04 AM
One theory, backed up by lab tests, is that the reactive trace gases in Venus' lower atmosphere -- at the planet's high surface temperature -- have caused small amounts of calcite and other carbonates in the soil grains to fuse them together, so that Venus' surface soil is "crunchy".
Yes, and in fact you can see the shadow of dust deposits downwind from some of the meteorite impacts.
It isn't completely clear that the penetrometer on Venera-14 failed. Basilevsky tells the story of it hitting the lens cap, but the scientists who ran the experiment say it touched the surface and returned some data:
[attachment=5521:attachment]
Very cool. Here is a perspective view from overhead, at the Venera-13 site. Notice the shadow all around the lander, as it blocks some of the uniform hemispherical light source.
[attachment=5522:attachment]
Posted by: tfisher May 10 2006, 01:31 AM
Excellent! This view really helps me to see the geometry of the images. Do you have (or can easily make) the other landers' images in this view?
Posted by: RNeuhaus May 10 2006, 02:33 AM
The next Venus's visit time by any other spacecraft would be Messenger's flyby on October 26, 2006. This spacecraft is carrying seven scientific playload, which are specially designated to study Mercury. However, some of its scientific instrument would be useful during its Venus' fly-by short time:
- Mercury Dual Imaging System (MDIS), a camera with wide and narrow fields-of-view, for monochrome, color and stereo imaging to take Mercury global pictures. It might be used during the Venus' fly-by.
- Gamma-Ray and Neutron Spectrometer (GRNS), which would be able to map the elemental makeup of Mercury's crust. Useless for Venus' fly-by.
- X-Ray Spectrometer (XRS), also used to map elemental abundances in crustal materials. It would not be used since the narrow mapping would not be justified.
- Magnetometer (MAG), which maps the detailed structure and dynamics of Mercury's magnetic field and searches for regions of magnetized crustal rocks. I think it would not be used since its usefulness is only valid if the mapping is of planet global range.
- Mercury Laser Altimeter (MLA), which measures the planet’s topography. Not used due to the same as MAG.
- Mercury Atmospheric and Surface Composition Spectrometer (MASCS), which measures the abundance of atmospheric gases and detects minerals in surface materials. It would be used during the fly-by.
- Energetic Particle and Plasma Spectrometer (EPPS), which measures the makeup and characteristics of charged particles within and around Mercury's magnetosphere. It would not be deployed on Venus' fly-by.
Then after Messenger, the other spacecraft, BepiColombo, funded by ESA and ISAS of JAXA, would be flying-by on its way to Mercury by the year 2011-2012 Rodolfo
Posted by: BruceMoomaw May 10 2006, 02:58 AM
- Mercury Dual Imaging System (MDIS), a camera with wide and narrow fields-of-view, for monochrome, color and stereo imaging to take Mercury global pictures. It might be used during the Venus' fly-by.
- Gamma-Ray and Neutron Spectrometer (GRNS), which would be able to map the elemental makeup of Mercury's crust. Useless for Venus' fly-by.
- X-Ray Spectrometer (XRS), also used to map elemental abundances in crustal materials. It would not be used since the narrow mapping would not be justified.
- Magnetometer (MAG), which maps the detailed structure and dynamics of Mercury's magnetic field and searches for regions of magnetized crustal rocks. I think it would not be used since its usefulness is only valid if the mapping is of planet global range.
- Mercury Laser Altimeter (MLA), which measures the planet’s topography. Not used due to the same as MAG.
- Mercury Atmospheric and Surface Composition Spectrometer (MASCS), which measures the abundance of atmospheric gases and detects minerals in surface materials. It would be used during the fly-by.
- Energetic Particle and Plasma Spectrometer (EPPS), which measures the makeup and characteristics of charged particles within and around Mercury's magnetosphere. It would not be deployed on Venus' fly-by.
There will be no science observations from Messenger during its first Venus flyby because, by bad luck, this occurs near solar conjunction and its radio signals will be blocked -- but they have a massive science campaign planned during the second Venus flyby, including the use of several instruments which you predicted would not be used: http://www.lpi.usra.edu/vexag/Nov2005/MESSENGER_VEXAG.pdf
Posted by: Rem31 May 10 2006, 08:52 PM
Maybe it will be possible to land a spacecraft at the (highest) point on Venus ,on a mountain i think because the temperature and the presure will be a bit lower at the highest point on Venus ,so a landing will be a bit easier then. But i dont know what the temperature and the pressure will be at the highest point at Venus. Anyone who knows about it?
Posted by: BruceMoomaw May 10 2006, 09:29 PM
Not that much of an advantage -- if I remember correctly, the temperature at the highest mountain top on Venus is less than 40 degrees C. lower than its average temperature. (I have a detailed sourcebook on the planet which may be able to give me this information precisely.)
Posted by: RNeuhaus May 10 2006, 09:37 PM
The highest point is located on the northern highland is named Ishtar Terra and has Venus's highest mountains, named the Maxwell Montes (roughly 2 km taller than Mount Everest) after James Clerk Maxwell, which surround the plateau Lakshmi Planum. Ishtar Terra is about the size of Australia.
About the temperature's posted by Bruce, it is interesting, at 10-11 km above of the Venusian's datum has a survivable temperature. However, I still have no picture or map of the Maxwell Montes mountain to see if the top has large flat to permit an acceptable landing risk.
Rodolfo
Posted by: Bob Shaw May 10 2006, 09:47 PM
Rodolfo
Rodolfo:
The mean surface temperature of Venus is 464°C - 40°C less than that is hardly what one might call balmy...
Bob Shaw
Posted by: Phil Stooke May 10 2006, 10:18 PM
Maxwell Montes is a large flat-topped plateau with plenty of room for a landing. It is geochemically distinct, so a prime target for landing. The slight temperature reduction would be useful, presumably, but it's an important goal anyway.
Go here:
http://pdsmaps.wr.usgs.gov/PDS/public/explorer/html/fmapintm.htm
for images.
Phil
Posted by: RNeuhaus May 10 2006, 10:44 PM
The mean surface temperature of Venus is 464°C - 40°C less than that is hardly what one might call balmy...
Bob Shaw
Ooppsss...
I haven't seen the word "less" Anyway, the cake would be tasty at that temperature!Rodolfo
Posted by: BruceMoomaw May 11 2006, 03:43 AM
Yes, that's a little bit reminiscent of that scene in the second Addams Family movie in which Uncle Fester, who's about to get married, is holding his bachelor party accompanied by a swarm of strange-looking male Addams relatives. Lurch wheels in the giant cake, at which point one of the Addamses wrinkles his nose and asks, "What's that burned smell?" Fester snaps, "Lurch, you're supposed to put the girl in the cake after you bake it!"
I will shortly be going through my photocopied sections of Arizona State University's authoritative book on Venus, which should contain the information we need on surface temperatures on Venus' highest mountain top -- but it can already safely be assumed that they will be almost as savage as those on the ground. I'll also be looking up the stuff that I have on the apparent chemical/thermal fusion of Venus' soil particles into a hard crust.
Posted by: edstrick May 11 2006, 10:03 AM
"....It probably wasn't capable. Remember, it was the Bus that relayed the multiprobe data back, not PVO...."
Pioneer Venus Multiprobe and Orbiter were entirely separate missions, using a common bus spacecraft as orbiter and cruise-stage and flown at the same time. There was minimal operational interaction between the two missions, necessarily, as one might have had a launch or inflight failure.
The Multiprobe bus did not relay data from the probes, it just did a final maneuver to target it for a shallow entry near the limb as viewed from Earth, and used an ion mass spectrometer and neutral mass spectrometer (I'd have to double check) to measure extreme upper atmosphere composition and structure before burning up in an entry fireball.
The probes were direct to Earth transmitters, something like 64 bits/sec for the small probes, 256 or 512 for the large probe. Data tracking was by the Deep Space Net, additional Differential Very Long Base Line Interferometry was used to do 3 dimensional tracking (not telemetry) of the probes motions in the atmosphere. The probes were atmosphere probes only with little or no design for post impact science. The large probe shed it's heat shield and probably had it's bottom smashed-in on impact. The small probes retained their heat shield and their simple atmosphere structure instruments looked out or were suspended over the heat-shield edge. One probe (Night?) went silent on impact, one lasted about a second (I never heard any further information on that smidgen of data) and the Day probe lasted something like 67 minutes, seeing a puff of dust on impact with the nephelometer, transmitting till it FRIED. The US successfully landed a probe on Venus without trying!
Posted by: DonPMitchell May 11 2006, 10:56 AM
With regard to temperatures and pressures, you want to get a copy of the Venus Standard Atmophere. http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1985AdSpR...5....3S&db_key=AST&data_type=HTML&format=&high=431278100116201.
I use this to derive altitudes for events where pressure and temperature are given. It's more accurate than the contemporary figures, for things like PV or early Venera missions.
Posted by: Ames May 11 2006, 11:22 AM
Page about Influenza from Venus??? but has a temperature profile from Magellan data.
http://www.datasync.com/~rsf1/vel/1918vpt.htm
Suggests that it would be tolerable only above 50Km where, strangely, the pressure is about 1000 millibars (roughly Earth sea level pressure) - Nice!
Nick
Posted by: tedstryk May 11 2006, 11:25 AM
http://www.datasync.com/~rsf1/vel/1918vpt.htm
Suggests that it would be tolerable only above 50Km
Nick
I will worry about that one right after we deal with those pesky body snatchers from Jupiter.
Posted by: DonPMitchell May 11 2006, 11:56 AM
LOL. The website suggests that the 1918 flu virus came from Venus. Call me a skeptic, but I don't think so!
The other day a plumber was at my house to fix something, and while he was under the kitchen sink working he casually said, "Did you know that lasers and integrated circuits and photonic networks were all found in the alien spacecraft at Roswell?". A few months earlier, a man inspecting my furnace had told me that the Apollo Moon landings were faked by the government. Then you have this British hacker looney who was breaking into NASA computers to find out secret alien "zero energy" devices. The internet is just filled with this kind of garbage information.
How can people believe such things? What is wrong with our schools?
Posted by: Rem31 May 11 2006, 01:11 PM
Is it true that you do not need a spacesuit when you are at an altitude at 20,30 or 50 kilometers (i dont know exactly how high) above the surface of Venus ,because the temperature and the pressure is almost the same like it is (at this moment) inside and outside my house. Can you explain that?
Posted by: Bob Shaw May 11 2006, 04:22 PM
While temperature and pressure and the bulk composition of the atmosphere might do you little harm, I suspect that the clouds themselves would be chemically very nasty indeed for humans!
Bob Shaw
Posted by: DonPMitchell May 11 2006, 06:55 PM
Bob Shaw
I lived in Pasadena in 1980, but I think the photochemical smog in the Venusian clouds is even worse! There is actually a little sulphuric acid in the upper atmosphere of Earth, probably from the same reaction as Venus:
(UV) + CO2 + SO2 -> CO + SO3
SO3 + H2O -> H2SO4
There are lots of other things in the clouds on Venus, especially the lower clouds. The Pioneer Venus large probe had a particle-size spectrometer that led some to think there might be large crystals in the lower clouds, although this is not so widely believed today (the so-called "mode 3 controversy").
The latest information comes from Vega-1 and 2, which had a battery of experiments for cloud study. There is a large amount of phosphorus in the lower layer, so some think it may contain phosphoric acid. Other possible components are Iron Chloride and Aluminum Chloride, which are both gases at surface temperatures. There is still really a lot that is not known. Probably only the upper clouds are simply sulphuric acid droplets.
I hope the ailing Fourier Spectrometer on VEX will recover and say more about this.
Posted by: BruceMoomaw May 11 2006, 08:43 PM
It might not be that much worse than L.A.'s smog. The clouds on Venus are surprisingly rarified. There are, after all, only very minute traces of both water vapor and sulfur compounds in Venus' air out of which droplets of sulfuric acid can be formed.
As with the haze on Titan, the fact that they block out our view of surface features from above is deceiving. I suspect, however, that in the case of Venus the explanation is somewhat different -- as Don pointed out above, even without any clouds the sheer density of Venus' CO2 atmosphere very seriously blurs features seen from any long distance through Rayleigh scattering, and I imagine the clouds just contribute to that effect in concealing Venus' surface features from our view.
Posted by: Bob Shaw May 11 2006, 09:27 PM
Bruce:
Am I hearing volunteers for a 'briefly manned' spa holiday in the clouds of Venus?
Actually, that might not be so far off the reality - look at the stuff in (allegedly) health-enhancing spa baths, especially those associated with natural hot springs!
Bob Shaw
Posted by: 4th rock from the sun May 11 2006, 11:53 PM
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More fun with the Venera images!
This is an atempt at creating a 360º pan, with a vertical 50º field of view, from the V14 images.
With so many pans from the Moon and Mars, Venus must have them to!
Posted by: Rem31 May 11 2006, 11:55 PM
Is there sometimes Sunshine on Venus or is the Sun (never) visible from the surface? Is there never a glimpse of sunshine at the surface of Venus?
Posted by: BruceMoomaw May 12 2006, 01:16 AM
On the contrary; there is a great deal of sunlight at the surface of Venus. It is, after all, close enough to the Sun that the intensity of sunlight hitting its cloud layer is about twice that at Earth -- and since about 20% of that punches through the clouds to the surface, surface illumination on Venus is about 40% that of daytime cloudless Earth. (What was less certain, until Venera 9 landed, was whether that sunlight was so diffused and dispersed in direction by the clouds and by Venus' thick atmosphere that shadows on its surface were largely washed out -- but the Veneras' surface photos reveal that even small bits of gravel have quite sharp and clear shadows, confirming that little of the incoming sunlight has its direction changed, either.)
Posted by: Rem31 May 12 2006, 02:09 AM
But the disk of the Sun is never visible at the surface of Venus or am i wrong? And is Suncream needed when i am in a (hyphotetical) spaceship with allround glass just above the clouds of Venus at its equator? Is the Sun burning there? Can somebody explain that?
Posted by: BruceMoomaw May 12 2006, 05:49 AM
Believe me, if the windows in your spaceship aren't UV-proof, you will need MUCH more than Suncream. The Sun's UV, when not blocked by our ozone layer, is sufficient to give you a very bad sunburn in a matter of 20 seconds or so even at Earth's distance from the Sun.
As for the solar disk seen as a clear entity from Venus' surface: it's extremely unlikely -- although I've never read anything specific on the subject.
Posted by: BruceMoomaw May 12 2006, 07:14 AM
Beginning my project of telling you more about Venus than you wanted to know...
For starters, there are two superb overviews on the Web of our current knowledge about the place: Basilevsky's 2003 article ( http://www.planetary.brown.edu/pdfs/2875.pdf ) and Fegley's 2004 book chapter ( http://solarsystem.wustl.edu/Ch21Venus.pdf ). Indeed, on rereading all this stuff, I find I made some mistakes of memory.
(1) Venus air temperature drops 8 deg C for every rise of 1 km in altitude (or 23.2 deg F per mile). Thus, "The temperature is ~648 K [375 C, or 707 F] and pressure is ~43 bars at the top of Maxwell Montes, which is ~12 km above the modal radius of 6051.4 km and is the highest point on the planet." (Fegley, pg. 18)
(2) "All of the clouds are low density because the visibility inside the densest region of the clouds is a few km. The average and maximum optical depths (rho) in visible light of all cloud layers are 29 and 40, respectively, versus average and maximum rho values of 6 and ~350 for terrestrial clouds. Average mass densities for Venus’ clouds are 0.01-0.02 g/cubic meter, versus an average mass density of 0.1-0.5 g/cubic meter for fog clouds on Earth". (Fegley, pg. 18) And remember that Venus' cloud droplets are pretty close to being pure sulfuric acid, which has a molecular weight almost 5.5 times that of water. These droplets are really sparse.
(3) "Venus has the highest albedo of any planet (e.g., 0.75 vs. 0.29 for Earth). Even though the solar constant at Venus (2613.9 W/sq. meter) is ~1.9 times larger than that at Earth, Venus absorbs only ~66% as much solar energy -- i.e. ~160 W/sq. meter vs. 243 W/sq. meter -- as Earth. The energy deposition is dramatically different from that on Earth, where ~66% of the absorbed solar energy is deposited at the surface. In contrast, about 70% of the absorbed sunlight is deposited in Venus’ upper atmosphere and clouds, another 19% is deposited in the lower atmosphere, and only ~11% reaches the surface. The 'sunlight' at Venus’ surface is ~5 times dimmer than that on Earth." (Fegley, pg. 18)
(4) For Basilevsky and Head's speculations that the "rocks" seen in the Venera photos are really fused layers of fine ejecta dust from nearby giant impact craters, see:
http://www.planetary.brown.edu/planetary/international/Micro_38_Abs/ms007.pdf
http://www.planetary.brown.edu/planetary/international/Micro_38_Abs/ms025.pdf
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1133.pdf
http://www.planetary.brown.edu/pdfs/2875.pdf (pg. 9-11). In the latter, note something I'd forgotten: "During the Venera 13 touchdown event, clods of soil were thrown up onto the upper surface of the spacecraft supporting ring (see the dark spots on the ring close to the view-port cover on Venera 13 panorama A). Five sequential images of this place taken within a 68 min interval showed that the spots were shrinking with time, obviously due to deflation by near-surface wind." (pg. 10) And all four landers (like Pioneer 13's one surviving Small Probe) optically detected a dust cloud on landing. Also, "Direct (anemometry and spacecraft Doppler tracking) and indirect (wind noise) measurements showed that at the Venera/Vega landing sites (on plains, close to the mean altitude level) at a height of 1meter above the surface the wind velocity is about 0.3–1 meter/sec. Bearing in mind the very high density of the near-surface air, the mechanical load of the wind on Venusian surface features is rather large." Judging from what Venera 13 saw, the earlier calculations regarding the effects of Venus' surface winds on its soil were correct -- they really do blow Venusian soil around rapidly, if it's loose.
But at the same time we have Magellan's bewildering but solid observations of the rate at which Venus' surface features erode. Quoting Robert Strom's 1993 abstract (available indirectly at http://adsabs.harvard.edu/abs/1993LPI....24.1371S ): "Parabolic features are associated with 66 of [Venus'] 919 craters... [which] range in size from 6 to 105 km diameter. The parabolic features are thought to be the result of the deposition of fine-grained ejecta by winds...Since 66 of the 919 craters have parabolic features and the average age of the surface is 330 million years, then the average age of parabolic features is about 24 million years, but could be as short as 14 million years or as long as 50 million years. This suggests that eolian erosion, particularly for unconsolidated material, or burial rate on Venus is extremely low, compared to the Earth or Mars. Campbell et al estimate that the thickness of the parabolic deposits is several to tens of cm thick, possibly 0.16 to 3 meters. If the deposits average about 3 meters thick, then the maximum possible erosion rate is about 210 cm per million years, and the minimum rate is about 60 cm per million years. On the other hand, if the deposits are only 16 cm thick, then the maximum possible erosion rate is only about 1 cm per million years and the minimum rate is about 3 mm per million years. These low erosion or burial rates make it unlikely that eolian processes on Venus have been important in shaping its surface." The Magellan team had reached similar conclusions earlier; quoting Kevin Burke's 1994 abstract (available indirectly at http://adsabs.harvard.edu/abs/1994LPI....25..201B ): "The surface of Venus...seems to lack evidence of substantial landform degradation, particularly in comparison with the other two terrestrial planets with atmospheres, Earth and Mars. Those impact structures on Venus that have escaped direct involvement in tectonic or volcanic activity show very little evidence of topographic degradation. They retain bright block ejecta deposits and steep rim topography. Despite the evidence of approximately a billion years of endogenic and impact surface processing, there are relatively few sites on Venus where loose particulate surface material is available to be moved by the wind."
How in the world do we explain this grotesque contradiction? Burke devotes his abstract to showing how, in lab tests, grains of silicate minerals of the type likely to exist on Venus appear to slowly react with the CO2 in its air ( not with its sulfuric trace gases, as I had thought) to form a surface crust of calcium carbonate that cements the grains together. "Chemical cementation is a plausible means of keeping the global inventory of particulate material on Venus depleted in the absense of ongoing surface activity, and may stabilize surface debris and preserve steep slopes associated with impact craters and tectonic features. If so, there may be no correlation between age and surface slope measured over short length scales...Steep slopes as well as aeolian features, such as dunes and wind streaks, may be stabilized structures that record ancient rather than recent events. In the absense of significant atmospherically driven weathering, topographic degradation would be dominated by volcanic processes such as burial under lava, or tectonic processes such as folding and faulting."
Finally, regarding the Veneras' other measurements of the properties of the "rocks" they saw:
http://www.lpi.usra.edu/meetings/lpsc2004/pdf/1133.pdf : "...[S]oil mechanics measurements indicate
that these rocks are mechanically weak and porous (density ~ 1.5 g/cc)..."
http://www.planetary.brown.edu/pdfs/2875.pdf (pg. 11): "At the Venera 13 and 14 sites, the bearing capacity of the rocks was measured by two techniques... It was found to be only 3–10 kg/sq. cm; this implies that the rock material is porous. This, in turn, implies that it may be weakly lithified aeolian sediment (e.g. composed of debris initially produced by meteorite impact) or volcanic tuff."
Posted by: ugordan May 12 2006, 07:36 AM
Again, I have to say that's a pretty lame excuse for skipping science on the first flyby. The s/c is performing pre-recorded observations anyway and I don't get it why they simply don't choose to delay the science playback a week or two?
If, as Bruce suggests, even the small pebbles have sharply defined shadows, that implies a well defined, point-like light source. So yes, the sun should be clearly visible as a round disk from the surface, though it's likely the rest of the sky is pretty bright as well.
Posted by: djellison May 12 2006, 08:53 AM
You don't want the spacecraft to be doing anything other than looking after itself, and maintaining appropriate pointing during Conjunction. Adding a science program into the mix would increase the risk of having a safing event, and frankly, on a Discovery budget - the money to get the people together to write, test, and then look at the resulting sequences and data isn't going to be easy.
Doug
Posted by: ugordan May 12 2006, 09:08 AM
True, but a safing event is equally as likely anytime, solar conjunction or not. Once the spacecraft safes itself, it should be... well, safe
Maintaining sun-point for solar panels and awaiting instructions from Earth. I don't see any non-catastrophic safing event doing anything bad to the spacecraft on a timescale of days (as opposed to hours when normal contact is maintained).
Though, you're right -- after all, this is a Mercury mission and anything beyond that is just bonus science. Reducing all unnecessary risks probably simply is good planning.
Still, one can't help but feel sorry about missed opportunities like this...
Posted by: djellison May 12 2006, 09:20 AM
Well - remember, it's not as if Venus is the ignored neigbour at the moment...we have VEX giving it the once over. Without VEX, I'd be inclinded to agree with you in that any Venus science would be worth it (i.e. a drop of water when you're really really thirsty is great...but do you care about a drop of water when you've got a 25 litre water-bottle on your desk )
Doug
Posted by: tedstryk May 12 2006, 10:43 AM
I don't think it is worth the risk. Should a course correction have to be made, and it ends up stuck in safe mode, it would be really bad news.
Posted by: edstrick May 12 2006, 11:03 AM
I'm a little suprised they aren't going to passively collect fields-and-particles data and store it for post-conjunction dump.
Posted by: ugordan May 12 2006, 12:01 PM
Course corrections would be made well in advance of the conjunction and the flyby, to precisely tune the flyby aimpoint. Why well in advance? Well, the same conjunction period would mess up the thing if the s/c ends up in a safe mode for days. So in any case, the TCM would be done BEFORE the flyby science and would not be jeopardized by the latter.
In case of a TCM performed AFTER the flyby, that also wouldn't present a problem as it would most likely be a cleanup maneuver and could be easily rescheduled with little delta-V expenses. Personally, I think the risk wouldn't be significant at all, but I'm not in charge of the mission and I can understand the mission folks-- a safe bet is a safe bet...
Posted by: DonPMitchell May 12 2006, 12:08 PM
No, I do not believe so. Take a look at the overhead-view projection I posted. The illumination on the surface is form the uniformly bright hemisphere of the sky, no point source. Between clouds and rayleigh scattering, I do not believe the disk of the Sun is ever visible on the surface of Venus.
I'm planning to do a multiple-scattering montecarlo simulation of this soon, because I want to see if the color of the sky might be different. The spectrum of the Zenith was measured, and the panoramic cameras see some of the horizon, but it is not obvious that the two parts of the sky are the same color.
[attachment=5558:attachment]
I generated this image a while ago, simulating scattering effects with data from Venus Standard Atmosphere. The image of Venus is rendered with 5 % of the actual density! That is because at full density, at this scale (200 km x 200 km squares), the true Venus atmosphere looks almost opaque near the surface.
Posted by: ugordan May 12 2006, 12:23 PM
I was merely following on Bruce's assumption.
It did strike me a bit odd the sun would be visible through the thick cloud cover and enormous atmosphere.This is awesome! This is the sort of rendering I see a lot of space simulation programs struggle to achieve (Celestia, Orbiter...). How did you produce this result and how computationally expensive was it?
Posted by: DonPMitchell May 12 2006, 12:42 PM
Thanks. Actually, computer graphics research is my "day job". This was a special purpose renderer done in C++. It's a steadily growing program called "BookGraphics", which contains a large number of totally unrelated subroutines, each of which makes a figure for my book. :-)
Posted by: Bob Shaw May 12 2006, 01:44 PM
Don:
You mentioned your book - can you tell us more about it, please? I'm sure it's one I *need* to buy!
Bob Shaw
Posted by: remcook May 12 2006, 03:34 PM
I only now see this thread properly and - wow - I don't think I've ever seen the horizon on these Venera images (even though it's partly copied). Great job don!
Posted by: DonPMitchell May 12 2006, 04:21 PM
You mentioned your book - can you tell us more about it, please? I'm sure it's one I *need* to buy!
Bob Shaw
I decided to write a book instead of just updating my website about the Soviet Exploration of Venus. I have a lot more material, photos and interviews with scientists, etc. I won't make back the money I've spent, which wasn't the point anyway. A problem with websites is they are not acknowledged officially, never reviewed, discussed or cited in the literature. You can't inject your work into the arena of public discourse unless you write a book, made out of paper and ink. Just a weird fact even in our modern times.
Posted by: Tom Tamlyn May 12 2006, 04:34 PM
Verba volant, scripta manent.
TTT
Posted by: Bob Shaw May 12 2006, 05:52 PM
Don:
Well, your website is a classic and one I've regularly visited, so I'm sure the book will be good!
Where are you in terms of publishers etc?
Bob Shaw
Posted by: DonPMitchell May 12 2006, 08:51 PM
Well, your website is a classic and one I've regularly visited, so I'm sure the book will be good!
Where are you in terms of publishers etc?
Bob Shaw
I'm writing and doing full layout now, and will look for a publisher when I've a book in hand.
Posted by: Rem31 May 12 2006, 10:37 PM
Sometimes i read about lightning on Venus ,but what is the truth about that? Are there thunderstorms like we have here on Earth?
Posted by: BruceMoomaw May 12 2006, 10:58 PM
The question is still not completely resolved, but the evidence is mounting against Venusian lightning. The strongest item is that Cassini made a very sensitive check for radio bursts from lightning discharges during its second and last gravity-assist flyby of Venus and found nothing. And, from what we know of Venus' weather at this point, it seems unlikely that there are any strong storm-like phenomena in its cloud layers that could build up the sort of massive separation of electrical charge that is necessary to set up the conditions for a lightning bolt. (Its clouds seem to be quite rarified virtually everywhere.)
To repeat, though: the question isn't totally settled yet.
Posted by: J.J. May 26 2006, 04:38 PM
Great pictures Don P., and great posts. Here's to hoping we see more great pictures from future missions!
Posted by: vikingmars May 29 2006, 04:36 PM
I confirm the images were reconstructed from RAW Russian Venera data given to me a long while ago...
Posted by: DonPMitchell May 29 2006, 05:12 PM
I confirm the images were reconstructed from RAW Russian Venera data given to me a long while ago... Looks like your image was genetated from this data, given to Brown University by the Vernadsky Institute:
[attachment=5944:attachment]
Posted by: vikingmars May 30 2006, 07:24 AM
[attachment=5944:attachment]
I can confirm to you that it is indeed RAW imaging data : please find herebelow, an example of the data I'm using to produce my final images (four of the V13 cam2 images for blue, green and red channels)
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Posted by: JRehling May 30 2006, 02:32 PM
TTT
Maybe more people would take a website seriously as a publication if it were in Latin...
Posted by: karolp May 30 2006, 03:53 PM
And what is that ball-shaped object almost touching the lander that looks like it has been munched by a dog and is now glowing where it was bitten? Seriously, I would like a nice explanation as I have not seen any references to it. Is it some kind of volcanic ejecta? Or a boulder crashed upon landing? Anyone?
Posted by: vikingmars May 30 2006, 04:34 PM
It's the protective cover of the camera itself, jettisonned soon after landing
Posted by: tasp May 30 2006, 05:04 PM
As I recall, (sorry I can't cite a reference) the landers are expected to always be colder during their descent than their surrounding atmosphere, so there is a concern that 'crud' in the atmosphere will tend to condense on the lander. In the case of a sensor trying to study the 'crud' this might be a good thing. In the case of a camera lens, not so good.
Posted by: DonPMitchell May 30 2006, 06:11 PM
I can confirm to you that it is indeed RAW imaging data : please find herebelow, an example of the data I'm using to produce my final images (four of the V13 cam2 images for blue, green and red channels) I worked for a while with that set of raw images from Brown (Jim Head sent it to me). But there are mysterious problems with that data. Here is an example of one of the Brown U "raw" images, together with the same section from the original 9-bit telemetry (which I got from RNII KP in Moscow):
[attachment=5953:attachment]
When I was working with the Brown data, I noticed that there are sections of the vertical scanlines missing. Not whole scan lines, but parts of scanlines, with little horizontal fault lines then running across the image. You can see by comparing the lengths that about a dozen full lines of data are gone. I cannot imagine how that happened.
Another problem with the Brown U. data is that it is only 8 bits deep, and the 8th's bit is randomly scrambled, possibly also by photoshop, so there is really only 7 bits of data. One of my goals was to compute both photometric response and aperture correction for the camera. Having all 9 bits of data per pixel was very important for this (the raw images are logarithmic encodings of photometric brightness).
Posted by: vikingmars May 30 2006, 07:43 PM
[quote name='DonPMitchell' date='May 30 2006, 08:11 PM' post='56311']
I worked for a while with that set of raw images from Brown (Jim Head sent it to me). But there are mysterious problems with that data.
Maybe it will help you : I was staying at Brown U. in 1984 when the tapes from Russia came to Jim's office with this very data on it : I think that Brown's is the "rawest" original imaging data available...
==> Congratulations, Don, for your nice imaging work !!!
Posted by: DonPMitchell May 30 2006, 11:01 PM
The very "rawest" data from the Venera probes is a series of repeated transmissions of 9-bit digital data. So there are actaully 3 or 4 versions of each camera transmission, with different noise and defects.
With all 9 bits, it is possible to reconstruct a 10th parity bit (which was sent from the lander to the spacecraft bus), and fix many portions of the images where the bit stream got out of sync. A lot of what looks like streaks of white noise is actually perfectly good data, just with the parity bit sitting in the high-order position. Then with all 3 or 4 transmissions, I was able to recreate an almost noiseless version of each camera transmission.
Deriving the photometric response of the camera (and the logarithmic amplifer) was another problem, and this has not been done correctly before. So it was possible finally to get linear brightness, and then convert that to the sRGB standard (which compensates for the response of television and computer monitors).
I still believe the color calibration has not yet been done correctly. I am still working with the Russian engineer who built the Venera cameras, to derive a true color balance. So don't completely believe the colors in any Venera images you see, including mine.
Posted by: DonPMitchell May 30 2006, 11:24 PM
I should add that in the late 1980s, Carle Pieters at Brown University took a crack at the problem of color calibration. They created a panorama from the red, green and blue Russian images, balancing the color channels. Their choices were informed by experiments on the thermochromic shifts of oxydized basalts and iron oxides at high temperatures, and from Venera-9 data which returned a reflection spectrum from the nearby surface that went into the infrared.
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1986Sci...234.1379P&db_key=AST&data_type=HTML&format=&high=446aa4046905684
Here is the image they produced:
[attachment=5960:attachment]
This is probably the best color result so far, but it has two probelms. First, it was based on an incorrect linearization of the data. And second, a somewhat more accurate result can be obtained by solving the spectral inverse problem for the camera (from the wavelength-dependent camera response).
Thermochromism and piezochromism are problems, because even the metal-oxide pigments that the Russians painted on the color test board were shifted in color by heat and pressure. Yuri Gekin measured the spectrum of the paint in their Venus simulator, under the proper heat and pressure, so that is helpful now. But the best result will come from data on the internal lamp used to create the calibration signals (seen at the top or bottom of the "raw" images).
Posted by: Bob Shaw May 31 2006, 08:28 AM
Don:
Are those *more* colour calibration squares on the circular base of the lander, below the teeth? I'd never noticed them before!
Bob Shaw
Posted by: ugordan May 31 2006, 09:31 AM
Why does there appear to be color fringing in the color composite, as if the 3 channels weren't correctly registered?
Posted by: paxdan May 31 2006, 09:46 AM
Are those *more* colour calibration squares on the circular base of the lander, below the teeth? I'd never noticed them before!
Bob Shaw
I can make out CCCP
Posted by: tasp May 31 2006, 02:20 PM
Are the colored dots on the edge of the probe (by the 'teeth') resultant from pebbles being blown onto the lander between the different exposures needed for color?
On the far left of the image, there does seem to be some color registration fringing. Perhaps the probe shifted ever so slightly between exposures.
Another idea; the outer skin of the probe would be expanding as it heated up, thus shifting the location of the imager just a bit between exposures.
Posted by: DonPMitchell May 31 2006, 05:41 PM
Are those *more* colour calibration squares on the circular base of the lander, below the teeth? I'd never noticed them before!
Bob Shaw
Yes, six standard polysiloxane enamels were painted on the extended calibration board and on various parts of the lander (red, green, blue, white, grey and black). The letters "SSSR" (looks like CCCP) are printed there too, many people don't recognize that because they are very blocky and covered with dirt. Internal reports from RNIIKP give the spectrum of those enamels at normal pressure and under the temperature and pressure of the surface of Venus.
But you are also seeing false color effects from the wind blowing dirt around, during the time that the scene is being scanned though different color filters.
Posted by: Borek Sep 14 2006, 07:37 AM
I've just noticed this article on space.com (via reddit), which is about Don Mitchell's work on Venera imagery:
http://www.space.com/scienceastronomy/060911_venus_images.html
Borek
Posted by: ljk4-1 Sep 15 2006, 01:45 AM
http://www.space.com/scienceastronomy/060911_venus_images.html
Borek
Discussion on the images, plus more, started here:
http://www.unmannedspaceflight.com/index.php?s=&showtopic=1410&view=findpost&p=67529
Posted by: climber Oct 10 2006, 09:02 PM
Don,
On the October issue of "Espace Magazine" (in french), there's an article called "Russian Back to Planetary Exploration" (approx translation ).
Talking about Venus they show your pictures (you're credited) and they say that your work is explained on your website : www.mentallandscape.com
Posted by: tedstryk Feb 21 2007, 01:19 PM
I have put my http://www.strykfoto.org/venera.htm back up. I am working on some new versions, but I figured that I needed to at least have the old ones on my site.
Posted by: aconnell Apr 8 2008, 06:21 PM
Hi all. I guess like everyone else I was totally dumbstruck when I saw Don Mitchell's perspective renderings of the Venera 13 and 14 sites for the first time. From what I understand there is some colour information buried in the original dataset but there are various problems and challenges in extracting it to give a true idea of surface conditions as the human eye might see them. In the meantime I was wondering whether any of you image wizards out there might consider producing 'best guess' colour versions of these fantastic views based on the information already out there - and maybe the Venera 9 and 10 sets as well ? I know this is a big ask - particularly from a 'newbie' - and you are all busy people. But I for one would be really grateful and it is nearly my birthday. In two and a half months. Well more like three actually. Al.
Posted by: tedstryk Apr 8 2008, 06:31 PM
This thread may be useful to you.
http://www.unmannedspaceflight.com/index.php?showtopic=1410
Posted by: vikingmars Apr 14 2008, 03:25 PM
Thanks Tedstryk for your kind remembrance..
And there is the final hi-res V13 image...
http://www.unmannedspaceflight.com/index.php?s=&showtopic=1410&view=findpost&p=23069
Posted by: aconnell Apr 14 2008, 03:49 PM
Many thanks for pointing out this thread Tedstryk. Wonderful images here courtesy of your good self and Vikingmars. Al.
Posted by: Juramike Dec 6 2009, 06:50 AM
[Mike wants to make pretty picture of Venus for outreach talk. Mike digs through websites and finds some processed images. Mike spends evening playing around aligning and messing with colors of the processed images he found, and only then does Mike find UMSF thread where all this has already been done......]
Here's my addition to the Venera 14 work and to the images done by Don Mitchell and Ted Stryk:
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If you can imagine standing in the center then it's a relatively undistorted view, sort of a faked polar projection. In reality, the two outer ends of Camera 1 Pan and Camera 2 pan should touch.
Posted by: Juramike Dec 6 2009, 07:10 AM
Cropped image showing "best" view forward. Perspective is that of sitting in a rowboat looking at the decking on either side.
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-Mike
Posted by: ngunn Dec 6 2009, 09:41 AM
Nice versions Mike. The Venera images have always been among my all time favourites from the entire space age. (How long must we wait for more views of that forbidding surface?)
Posted by: 4th rock from the sun Dec 6 2009, 01:40 PM
Nice image compositions :-)
One of my favourite Venera visualizations is this :
http://www.astro.uni-bonn.de/~dfischer/mepco/venera.jpg
It comes from this page: http://www.astro.uni-bonn.de/~dfischer/mepco/
It's an early attempt to correct the image perspective.
Posted by: Juramike Dec 7 2009, 06:19 AM
Wow! Thanks! That was really helpful!!!
Here is a reprojected image using Daniel Fischer's diagram as a guide, then using the reprojected camera I image as a guide for the camera II side (happily, the symmetry was extremely helpful!):
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A higher res version TIFF is on my flickr site (6.5 Mb TIFF): http://www.flickr.com/photos/31678681@N07/4164881557/
To pretend "being there" attach the two ends of the strip together to complete the full panorama.
-Mike
Posted by: Juramike Dec 7 2009, 06:27 AM
Here's a polar reprojection that's been further warped:
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(And attempted vortex-fisheye modifcation didn't produce pleasing results.)
Posted by: ngunn Dec 7 2009, 08:38 AM
AndyG's your man for that. I keep hoping that he will do more than the two endless panoramas he has given us so far, or that others will pick up on the technique.
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