As soon as I uncovered the Martin Marietta studies for follow up Viking landers launched during the 1979 launch opportunity over at the NTRS, I've started wondering just how far into the planning process did they go?

Did they get as far as picking landing sites? And if so what were the planned targets?

As far as I remember, looking through files at JPL, the only alternates sites mentioned to be more investigated for a Viking 3 rover landing in 1984 were those of "C1" and "C2". "C2" was 355°E/9°S... This last one being just south of Opportunity's site and could have been chosen, not for hematite of course, but just because it looked more "smooth" for a landing there with Viking technology. The "A" and "B" sites were already dismissed for their roughness. There was still a prime site to land on Mars, the "A1" site. But it was thought to be very rocky and thus unreacheable with the Viking technology with only 25cm available room under the lander boby. This "A1" site became later the Pathfinder Ares site...
Also were mentioned for a 1984 landing :
- "Capri Chasma", on the north rim of Valles Marineris ;
- "Candor Chasma", where it could explore more than four kilometers of rock thickness...

BUT BEFORE the 1976 landings on Mars, there was some assumptions made with Mariner 9 data which gave the following 4 alternate sites to be chosen for a landing in 1979 with a Viking lander modified with some sort of mobility :
- "Cebrenia", at 32 degrees N, 211.5 degrees E :
- "Syrtis Major" at 6.5 degrees N, 292.5 degrees E ;
- "Mangala Vallis" at 6 degrees S, 150 degrees W ;
- the South Pole at 82 degrees S, 83 degrees W...

Olivier, do you know where the C1, C2 discussion might be found? I have the other roports.

I think it's true to say, though, that all these sites were only exampes of what might be possible for these missions, not actual mission pans. That is certainly true for the earlier study. Look at MER or MSL, for instance. The real site planning only gets going during spacecraft development. If the mission is ony in the study or proposal stage, only suggestions of sites, or constraints, are made.

Phil

[quote name='Phil Stooke' date='Dec 16 2007, 06:19 PM' post='105759']
Olivier, do you know where the C1, C2 discussion might be found? I have the other roports.

Phil,
I Must investigate more, because what I can find quick are my personal notes stating that the C1 & C2 discussion was only started after the launch of the Lander and based on Mariner 9 imagery only. C2 was quickly dismissed in May 1976 for a landing in July because it was becoming hotter being in early spring there. The main idea was that if any volatiles present (ice), they would have vanished under increasing seasonal heat and obviously after solar conjunction it would have become no more suitable for the life experiments. c1 site was the least preferred among the "C" sites : it was just a backup in case the "A" and "B" sites were declared unsuitable for landing. All that remained was the C2 site then... Just imagine VL1 landing in Meridiani planum !
Enjoy this nice photomontage, done as a tribute to your wonderful cartographic work !

Nice, VM!

Yeah, I've wondered a few times how we would've viewed Mars if one of the Vikings had landed @ Meridiani. I suspect that its more Earth-like appearance might have stimulated greater exploratory efforts...but, who knows. All speculation.

I noticed a photo of the Viking 3 lander body about 1/4 of the way down this page:

http://www.atmos.washington.edu/~mars/

Interesting to hear how it was rescued from becoming "molten scrap"...

...at the insistence of Prof. Tillman's daughter, no less. Good call, kid!

If a Viking had landed within sight of a crater, then Meridiani might have been quite a teaser, but then it may also have landed in the middle of nothingness, and the blueberries don't at a glance look all that Earthlike.

I think the "frost" pictures at Viking 2 had the most earthlike feel of just about anything we've yet seen at Mars, although that hinged on misleading appearances.

The V2 frost pics were quite striking indeed, although captured rather late in the mission (1978?) and therefore largely escaped the notice of the general public. I'm hoping that Phoenix can capture building drifts of clathrates before she goes silent (sigh... )

In fact, this famous VL2 frost picture was taken on sol 960 (i.e. may 18, 1979).

About Jim Tillman's Viking Flight Spare Lander "FC3" : this one is rebuilt from spare parts found independantly at various Lockheed-martin plants (former Martin-Marietta). We owe to Jim a great preseverance in promoting Mars meteorology and science : I was working on Viking data at JPL when he set-up his wonderful "live" exhibit at the Air & Space Museum in Washington DC in 1982, and helped the IPL at JPL feeding his TV monitor there on an automatic mode with images directly coming from Mars. But, the REAL Viking III, if launched, would have been the spacecraft still on show at the Air & Space Museum in Washington, which is a FLYING model that is only lacking its computer (not needed when built, because it was teleoperated from JPL in its Mars "sandbox" to simulate actions to be taken bythe landers then on Mars...)

Going back to the original topic - It's not really true to say that the four sites mentioned would have been the real landing site list if the mission had flown. This was from a study of rover missions done by the USGS under Hal Masursky in 1974. The only imaging data suitable for mission planning were Mariner 9 B-frames - high resolution frames, a very limited data set. USGS made mosaics of two or three frames in the very few places where that was possible, and made geologic maps of those places, in order to see how many different geologic units could be studied within a reasonable traverse distance. So rover routes were mapped out, and it's quite an interesting study. But if the mission had flown, a whole new site planning study would have been made using Viking images.

Phil

It would be nice if it does get some frosty views before it dies. Here is my version of the famous Viking shot using super-resolution to make a version that looks good at a decent size.

Click to view attachment

Just in case it's available online somewhere, the Viking rover document Phil Stooke referred to is NASA CR-140391, titled "Viking Rover Studies" by Harold Masursky, J. M. Boyce, and A. L. Dial. I was lucky enough to randomly obtain a copy of the preliminary version, which runs 39 pages. A fun little report.

here is the document :
Click to view attachment
The science thoughts and envisioned landing sites are very nice with the little knowledge of Mars they had then : the rover would have done really great science !
Enjoy