Now if I use IAS viewer just maybe we can find the mars 6 lander my eyes are straining already

http://hirise-pds.lpl.arizona.edu/PDS/EXTR...RED.abrowse.jpg



I wonder if we know what the landing ellipse would have been or was intended to have been on this image?

We don't have figures for target ellipse size (as far as I know), but it's not a case of 'where is the landing ellipse in this image', it's 'where is this image in the landing ellipse'.

The HiRISE images are about 6 km across. The Mars 6 target ellipse was probably about 200 km across, the landing coordinates are probably only known from tracking to about 60 km (1 degree). My guess - this image covers less than 1 percent of the area that would have to be searched.

Phil

Yeah...hate to say it, but I'm almost convinced now that the early Mars landers will only be found by some poor SOB literally tripping over them in a spacesuit in the 23rd Century or so. The recent dust storm provides ample evidence that Mars can and will easily conceal small-scale topographical disturbances within two decades.

If that assumption is accepted, then MRO's lander-finding efforts (if any) should be dedicated to Beagle 2 & MPL before vital collateral landscape disturbances are erased.

If it is found it would be awesome!

Something I was looking forward to!

Well, that's how Mars 3 (or was it 2) got found by a character in Mars Underground by William K. Hartmann. Hard-SF story, ok on the hard-SF, so-so on the story.

I Googled dust storms on mars and after a few hours I found evidence for 11 documented planet wide dust storms in the last 100 years, (1920,1956,1971,1973,1977,1982,1994,1997,2001,2003,2007)

Since the 1970s they come every 4/5 years, since 1920 it averages 8+ years (probably due to better surveillance in the last 30 years) We also know the the Hellas Basin brews yearly and regional dust activity as it is a warm, deep, and wide dust bowl itself, and a regional storm can erupt into a global storm as we saw in 2007 (chaos theory anyone?)

We also see local cleaning events by gusts of wind (oppy & spirit). I think an exposed object (lander) will accumulate dust but then it blown away year after year. I think the local cleaning events outnumber the dust accumulation events.

Evidence: Viking parachute (hardly a tall and exposed object like a rover -etc) is still quite visible after 6 major dust storms and 30+ years (in fact you can make a case that a parachute is quite a dust collector being so low and flat)


I hope to see much more Mars Hardware on the ground from MRO over the next few years!

Keep Looking!

You could well be right, PDP; I hope so! Unfortunately, with the exception of Mars 3, we're probably looking for holes in the ground for the other lost landers...might be pretty hard to discriminate them from garden-variety craters in their vast landing ellipses.

Still, there really is always a chance. If anybody can find them, it's the imagesmiths of UMSF.com!

Evidence: ONE of the Viking parachutes is quite visible, the other is barely visible, and fresh rover tracks only a few years old have been eradicated in places at both MER sites.



Doug

Hey Doug, I guess I should have said 'selective' evidence!

But, it is my contention that flatter objects will be obscured first on Mars.
In fact the rate any object will be obscured is directly proportional to the object's flatness to the ground.

The only kind of erosion on mars at the present is wind & dust based, and that takes a very long time to change things (unlike water!)

And what could be flatter than a deflated parachute or a MER track!

The MER tracks are also made of the same base material doing the erasing.
As a contrast both 30+ year old Vikings still stand out brilliantly as well as their back-shells.

There have been numerous cleaning events (6?) between both MERs over the last 3+years; and only one global dust storm in the same time. I think cleaning events on non-flat-to-the-ground objects wins at least for a while (hundreds of years?)

The pattern left by Oppy's backshell retro-rockets: it's now gone, and what was it?
First off, we know it was very flat: 1mm to 4mm at the deepest and probably a lot less as an averaged 'whole'.

Did the exposed material change color based on direct exposure to light and weather? Was other material blown in?

I don't know anything other than it was as made of dirt and flatter than MER's equally disappearing dirt tracks.

I think any piece of hardware at least 3X the size of Sojourner (and is not crumpled and flattened) will be visible to MRO. (IMHO!)

The biggest problem will be to return the VAST amount of hi-res pictures from the landing ellipses of all the landers that haven't been found yet. That's a lot of data (750+ highest resolution pix?) and we really cant point the camera and shoot off 1000 pictures, we have to wait until the space craft is directly over each area of interest to get the next piece of the puzzle!!!

(in the mean time, the scientists want their camera back for other purposes)

The only thing we can do is: Keep Looking at all the returned pix!

The Mars 6 combined lander and bus is said to be 2 metres across at its widest , which is across the big heatshield which looks like a Chinaman's hat . The lander is a roughly spherical capsule of no more than one metre width inside that heat shield. If it landed successfully and delpoyed, then petal-like panels opened out to increase its apparent width in 2 axes, much like Luna 9 and 13.

Mars 6 type lander image

That is the approx size of what we are really looking for.... it's pretty small

Kenny

The size and shape (and with dust, the colour) of a big mars rock.

Doug

Well, maybe more like a middling sized rock, rather than a big one. And the chute will be a lot smaller than Viking's, all twisted up and dust coloured, as has been said. Chances of spotting anything in HiRISE ? ... approximately zero?

Kenny

well........... the Viking images are remarkable in that they seem clearly visible from orbit, dust devils maybe cleaning them up as they do with the MER rovers.

The only reason we can identify the Viking landers in HiRISE data with certainty is that we know where to look in the first place, especially looking at the surrounding landscape features as well. I expect you could find a dozen Viking look-alikes in the same images, but they would lack the suite of surrounding features to clinch the deal. Parachutes are a different matter, they are unusual in appearance - but having seen all these bright outcrops around the rovers, I think future parachutes in outcrop-rich areas might also be more ambiguous. At any rate, even if Mars 3 or Mars 6 were relatively clean, they will be almost impossible to distinguish from rocks if there are lots of rocks in the area.

I would certainly encourage people to look at the HiRISE images, but it will be very hard to be sure of those Soviet landers even if they are in the image area.

Phil

Just another thought on this....

If the Soviet Mars landers are bright, shiny, silvery metallic (unlike Viking), and get periodically cleaned by dust devils, they might just glint nice and bright under certain angles of illumination. Recall the dazzling sight of the metallic interior of the Spirit heatshield on the rim of Bonneville seen from the opposite rim....

Kenny

99.99 percent of dust movement on the Martian surface is due to straight-line winds, not dust devils. I wish we could lose this obsession a lot of people have with "dust devils" being responsible for every cleaning event of every surface on Mars... *sigh*...

-the other Doug

Kenny, not bad thinking, but consider the variables:

1) The surface of Mars 6 has to be pretty clean and reflective, which is a random situation if possible at all by this time.

2) The illumination angle must be favorable to produce a specular reflection, and

3) MRO or another orbiter has to make a pass at exactly the right time of day (referenced to the surface) to detect that glint.

Given the fact that we have no idea what the orientation (much less the condition) of Mars 6 might be, gotta give this strategy a low probabilty of success. Still, keep thinking!

We have a better chance of finding Mars 3, since it actually landed as opposed to crashing. It is hard to tell what is left of Mars 6.

I perhaps better than anyone can tell you that finding a false Viking 2 is quite easy, as I myself found 2-3. The best bet actually is using HiRISE color images. A lander could also be fairly easily be verified if it soft-landed because of it's steeper-than-martian height, on average, landers are 2 times taller than most rocks on Mars.

The best bet to find a lander, however, with HiRISE is in the color. A lander tends to be reflective in all 3 bands, which is quite rare for so small of an object on Mars, in fact, it's quite rare for anything. But the color strip being so small, well, it would use far too many HiRISE images to find the site.

Mars 6 is easier to find, BTW, because it's landing ellipse is smaller, I think by an order of magnitude or so.

I take it that's also assuming that it executed a nominal landing sequence & didn't go splat...?

Statistically speaking you are right. I wasn't talking about the amount of area one needed to search. I was talking about identifying it once we saw it.

The geometry may not have to be as precise as you assume, nprev, because Mars 6 (or 3) is roughly spherical and metallic, and if it's clean it will be reflecting at just about every angle. This is quite unlike a flat sheet such as an Iridium solar panel which generates very narrow angle flares from sunlight, if you're familiar with those. So that characteristic of a metal sphere might take care of your points 2) and 3) somewhat, but we're still left with 1) as a big issue, I agree.

http://nssdc.gsfc.nasa.gov/database/Master...og?sc=1971-049F

I find it almost impossible to believe that that could be identified unambiguously as being different from any medium sized rock. Given the near invisibility of one of the two Viking parachutes - the chances of finding a 'region' to look at are not great, and the chance of finding the lander within that region are very low. I wouldn't get your hopes up.


Doug

Doug, the photo you link to above, being color, is better than the one I offered earlier at Post # 10 , which is only B&W. Yours shows the lander to have a white coating of some sort rather than bare shiny metal. So its basic reflectivity will be lower than bare metal, and the painted or coated surface may be more likely to have dust adhere to it. So the chances of spotting it are indeed further reduced.

Both the Mars 3 and Mars 6 landing ellipses are thought to be about 5 degrees across, or about 300 kilometers. It would take about a thousand HiRISE images to cover these ellipses. A member of the HiRISE team put in the target for Mars 6, and I added one for Mars 3 a month or so ago. Don't know when/if it will be acquired.

Mars 6's ellipse is centered over Samara Vallis, which is a Grand Canyon size valley network. Considering the nature of the loss of the lander (parachute thought to have deployed, impact at 60m/second), it may be that the lander encountered a steep slope before it could slow it's descent (retro rockets? I don't know, actually). So it might be possible to focus a search on things like crater rims and the walls of Samara Vallis.

Still, such a search would require hundreds of images. So I wouldn't recommend re-imaging the site unless there's something scientifically compelling to be imaged as well.


So, yeah, likely someone will have to trip over the thing while walking their dog in a hundred years or so!

-Tim.

In 'The difficult road to Mars' V.G. Perminov describes the fact that on the Mars 6/7 landers an additional transmitter was installed in order to receive atmospheric data during the descent (as opposed to the Mars 2/3 landers which did not transmit scientific data during descent), where after Perminov makes an interesting note on page 65: "the additional transmission channel was operative only during the descent of the lander. Information from the Martian surface had to be transmitted by the main radio channel to the Mars 5 spacecraft".

In other words, the Mars 6 main bus was only used as relay during the descent, it was not equipped to receive and relay signals on the main radio channel, used after the lander deployed on the surface. The Mars 5 spacecraft, orbiting Mars, would have to be used as a relay station for all surface operations, however contact with Mars 5 was lost on Feb. 28 after only 22 orbits, long before the Mars 6 lander arrived on March 12.

We will never know whether or not Mars 6 successfully landed and completed its program, the landing was doomed from the very start as there was no operative orbiting relay station and the main bus was only equipped to receive signals during the descent, using a different channel/frequency then the surface station...

It crashed. It was going far too fast when it impacted to have possibly survived. Mars-6 had been unable to receive commands for months during the approach, so it is amazing it got as far as it did, but there was no way to make the final tweaks to ensure a safe landing.

AFAIK we have no absolute proof of this.
The Soviet landers were designed to descent quite fast, descent speed on parachute was intended to be around 65 m/sec (ref. Perminov, page 45), according to the signal Mars 6 was descending at 61 m/sec when contact was lost (ref Brian Harvey, "Russian Planetary Exploration", page 158).

Furthermore, signal was not lost when contacting the surface, but the transmitter was designed to be shut down when the soft landing rocket was started (ref Perminov, page 45), so all we know is that at signal cutoff the craft was still descending conform the intended program and at the intended descent speed.

The solid fuel softlanding rocket engine was started at 16-30 meters height above the surface, however the start of this rocket was not only depending on the radar altimeter measured height but also on the measured descent speed, so a correction was applied if the craft was descending faster or slower then intended. Once the descent speed was reduced to 6.5 m/sec the lander was detached from its 'backshell' and dropped to the surface. The lander was tested to withstand a touchdown with a vertical descent speed of 12 m/sec and horizontal speed of 28.5 m/sec, withstanding 180G on touchdown so they were quite sturdy.

After touchdown, the aeroshell cover was separated, and the flaps were opened, pushing the craft in a vertical position, where after antenna's were extended. Signals from the surface were intended to be transmitted to the Mars 5 orbiter (while descent data was transmitted on a different frequency to the Mars 6 flyby bus), however this orbiter was no longer functional when Mars 6 landed, in other words there was no relay and we will never know whether or not signals were transmitted from the surface.

Yes, we do. There was Doppler tracking all the way down. The flyby bus and ground tracking should have at least detected a signal if it survived. Even Perminov blames a steep hill for the loss of contact. The Russians never suggested that Mars-6 operated on the surface.

We have doppler tracking as long as there was a radio signal, point is when did the signal stop?

The transmitter was designed to be switched off when the soft landing rocket was fired (Perminov, page 45) at a height of aprox. 16-30 mtrs, if this is indeed what happened then doppler tracking shows only the parachute descent speed (61 m/sec) and not the final touch-down speed. As far as I can find in the various archives there is no clear proof whether the signal cut off due to a crash or due to firing of the descent engine.

Perminov states "Information from the Martian surface had to be transmitted via the main radio channel to the Mars 5 spacecraft; however, the signal did not reach its destination" (page 65), what he fails to mention is that the Mars 5 orbiter failed on February 28 and was long dead by the time Mars 6 and 7 arrived, which at least explains why the signal "did not reach its destination".

If Perminov is correct that the surface signal HAD to be relayed via Mars 5 (and he is the one who should know), then the whole landing was doomed from the very start and there never was any option to receive a surface signal with Mars 5 long dead...

As a true diplomat, Perminov uses very carefully phrased words, he states "Perhaps the landing occurred on a steep hill?", which is indeed possible given the nature of the landing area, however he does not clearly blame this for the loss of contact. I presume that a steep slope might result in erroneous readings of the radar altimeter, triggering the firing of the descent rocket too early or too late (more or less what happened to Luna 18 on the moon?), and this might result in a crash. Similarly, if the radar altimeter was not working, there would never be a firing signal to the descent rocket and the loss of contact would indeed be a crash at the measured 61 m/sec doppler speed, however this is all just speculation.

Over the years I tried several times to calculate an exact time-frame for both the Mars 3 and the Mars 6 missions, especially with regards to the position of the relay-orbiter in the sky over the landingsite (with regards to Mars 6 this would be the trajectory of both the Mars 6 flyby bus and the Mars 5 orbiter), this would explain a lot regarding the complexity of the signal-relay (there was no direct-to-earth link). However, ephemeris data on Mars 3, 5, and 6 is very vague and resulting accuracy is far too low to give a clear answer as to when the various crafts were within radio range above the selected landingsites. If anyone ever found clear ephemeris data on the Soviet orbiters and flyby craft I would be grateful.

Ted, you said that Mars 7 sent back some scientific data from the Asteroid belt (?). Can you give me some links about that?

This is the only link I have handy:

http://adsabs.harvard.edu/abs/1977RaEl...22Q.260I