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Building the Viking Lander - again after 37 years


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This build is a bit of a trip down memory lane for me as I first built the Viking Lander almost 40 years ago (37 to be precise!) and recently I got a hankering to build it again. The original model has long since gone ... so too has the original copy of the Airfix magazine.

Fast forward to a few weeks ago when with the help of Mr Google and Mr Ebay I acquired a copy of the Airfix magazine, dated January 1977 containing the Viking Lander build.

I found an old photo of me taken sometime in 1977 slaving over the Viking model. The only information I had at the time was the Airfix magazine and the Viking Project document you see in the photo (not sure what that was and where it came from).

How times change ... now there are literally hundreds of photos of the Lander available on the net. My plan is to use the photos available to embellish the model (a bit) rather then being 100% faithful to the original instructions.

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The starting point ... the article in the Airfix magazine and some plastic card.

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I started with the Lander body. Following the description in the magazine article was a little 'interesting' as the drawing of the Lander body in the article isn't quite correct. The instructions suggest drawing a circle about 2 3/8 inch in diameter (ca. 70mm in today's money) and then marking off 9 sectors each of which span 40 degrees, then cutting the card to shape. So far so good ... until you compare the card shape with the actual drawing in the magazine. My first attempt was too small at one corner. Second attempt was also too small ... third attempt on paper drawn using a computer program ... also too small at one corner. It turned out the drawing was wrong as one radius was 38mm in length and not 35mm.

Once I realised there was an error in the drawing and not my card, it was relatively straight forward to make the Lander body. I added some strips of card along the top and bottom sheets of the Lander to provide some support for the walls of the Lander body. The pink stuff you see is Plastic Weld which is just painted along the join to 'weld' the plastic sheet together.

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Top and bottom sheets glued in place. It's beginning to look like something now.

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  • 1 month later...

Another update to the Viking build. Sorry it is taking so long. I thinking building the real ting and sending it to Mars would be quicker then this build ... ah well.

In the original Airfix article, the legs are attached to the body via two plastic strips forming an 'A' frame. Since then lots of images have been published to show that the legs are attached to a pillar type structure which I made from plastic square tubing cut at an angle. I added some detailing and a thin plastic 'sandwich' at the top into which the top of the legs will fit.

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Parts for the legs and pads. The legs are made from plastic tubing. The supporting arms are made from 'girder' shape plastic shapes and are supposed to hang below the body. Note the thin plastic rod at the very end of the legs. This bit will go into the 'sandwich' at the top of the leg support frame.

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First attempt at putting it all together.

I must admit that I had two attempts at attaching the legs to the body. The first attempt looked a bit odd ... the body was too high and didn't look right so off came the legs ... back to the drawing board.

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The radioactive thermal generator (RTG) fuel tanks are 1 inch (25.2mm) diameter wood balls which will eventually be glued onto a thin brass rod that passes through the lander body. I thought this would be a better way to secure the balls to the body ... no giggling at the back.

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The lander is beginning to take shape. Next job ... building the RTG covers.

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How will you seal your balls and still keep them spherical? That was so difficult to type with a straight face ^_^

Seal your balls ... hmmm ... very gently perhaps. :hypnotised:

I'm in two minds whether to add a thermal blanket. Some photos show the balls ... 'naked' ... others show then within a rough looking thermal blanket. If I go with the rough blanket, then it doesn't really matter if they don't look spherical.

Pete

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Glueman, what you call "radioactive thermal generator (RTG) fuel tanks" are in fact the descent engine fuel and oxidizer tanks. The RTGs (typically cylindrical with heat radiating fins) are mounted on the deck next to the tanks under their wind covers.

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How will you seal your balls and still keep them spherical? That was so difficult to type with a straight face ^_^

maybe have them hanging in some kind of sack ?

Edited by hendie
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Glueman, what you call "radioactive thermal generator (RTG) fuel tanks" are in fact the descent engine fuel and oxidizer tanks. The RTGs (typically cylindrical with heat radiating fins) are mounted on the deck next to the tanks under their wind covers.

Hi Blanik,

Thanks ... yes, you are correct about the tanks ... they are fuel tanks and not radioactive thermal generators. In all the excitement of the build I was getting a bit carried away. I'm actually working on the wind covers as we speak ... pesky little things, odd shapes and sizes.

Cheers

Pete

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Hi Blanik,

Thanks ... yes, you are correct about the tanks ... they are fuel tanks and not radioactive thermal generators.

Pete, in case you want to detail the RTGs I found a document titled "TAGS 85/2N RTG POWER FOR VIKING LANDER CAPSULE" on g**gle with the most detailed RTG views I've seen up to now.

I wish I had the time to do some spacecraft models... I'll follow your build closely!

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  • 2 weeks later...

Hello Pete, I came across this thread while doing a web search recently. I am very keen on the Viking '75 project and the lander in particular. I recall following the missions live as a teenager in the 1970s. In the last few years I have gotten serious about researching the lander hardware. I have some references which might be of interest to you. Here is a set of web albums I've created:

Proof Test Capsule (PTC) Lander in Smithsonian NASM (466 photos): http://tinyurl.com/kxdsceh
Science Test Lander in Virginia Air and Space Center (277 photos): http://tinyurl.com/kwh3rar
Flight Capsule 3 (backup) Lander in Seattle (683 photos): http://tinyurl.com/mr38mbb
Thermal Effects Test Model (TETM) Lander in California Science Center (138 photos): http://tinyurl.com/k74met8
Dimensioned diagrams of the CSC's lander: http://tinyurl.com/maa6trw
Body assembly blueprints: http://tinyurl.com/km83rlr
Misc diagrams, unusual photos (300+ images): http://tinyurl.com/kna5re5
In an earlier post you were writing about the overall dimensions of the core lander body. The blueprint set I have yields a definitive answer. The body is 18.000 inches high. The long hexagonal sides are 43.359 inches, and the short hexagonal sides are 24.566 inches. (Martin Marietta, the creator of the lander, used inch units with dimensions specified to a mix of 0.01 or 0.001 inch resolution.) Here is a post on the Unmanned Spaceflight forum where I describe the blueprint set in more detail: http://www.unmannedspaceflight.com/index.php?s=&showtopic=7327&view=findpost&p=200776

After a bit of surfing I managed to find some detailed measurements for the wind covers. Going to be tricky making the odd shapes.

I would be very interested to know where you found wind cover information? I've been fortunate enough to measure various aspects of an actual lander test unit, including a wind cover. The above "Dimensioned diagrams" album contains an annotated wind cover image with my measurements.

I have been working on a high-fidelity 3D digital model of the lander in my spare time for over a year. The last few images in the above "Misc diagrams" album shows renderings of my first version of the core body. I've since started over from scratch with new information that allowed me to achieve better accuracy, with most features located to within a millimeter or less (many exactly on, based on the blueprints). The overall scope is to include all fastener holes, as a measure of planned detail.

Best of continued luck with your Viking lander model!

-- Tom

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Hi Tom,

Many thanks for your post.

I put my hands up ... the information for the wind cover comes from your site Dimensional diagrams of the CSC Lander. Sorry, should have acknowledged you in my post.

Making some progress with the wind covers. I've made the lower half and are trying to work out the best methods for making the upper part. The upper section is a very complicated shape. The top is flat ... the bit that faces to the balls is also flat but the rest of the top is curved. Did think about carving the shape from balsa but I may go for a series of horizontal slices made from plastic card to build up the shape and then cover in filler or Milliput and then sand to shape. It'll come to me ... eventually.,

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Edited by glueman
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  • 7 months later...

Just received a signal from ground control to wake me up after almost 8 months in deep sleep ..... bleep ... bleep.

Had a bit of brain wave about how to make the wind covers for the RTGs. I eventually came up with a cunning plan.

I cut out a base from thin plastic card which was slightly smaller then the base of the wind covers. I then glued on a short plastic tube, 15mm in diameter and about 10mm in height. This tube forms the core of the wind cover.

Then out came the Milliput, the standard Yellow-Grey variety :)

I built up the rough shape of the wind cover by wetting the Milliput before it started to harden. Got quite a good shape. I left the Milliput to harden for a few days.

The photo below shows how I'm building up the rough shape of the wind cover.

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This photo shows the wind cover after a bit of sanding.

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The finished wind covers after more sanding and topping-off with a bit of plastic card. I'm very happy with the end product although the shape is not exactly 100% perfect ... but it will do.

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Time for another hibernation ... :sleeping::sleeping::sleeping::sleeping:

Edited by glueman
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A few tips when using Milliput -

First cut off the crust on the dark green component, it does not set properly if left in.

Second leave it for about 10 minutes after mixing before using it(it is less sticky and works easier).

Third setting time is very temperature sensitive. Below 5C it takes 3-5 days, it takes about 3 hours at room temperature(15-25C) and at about 50-60C its sets in about 30 minutes. I don't recommend heating above room temperature if combined with plastic parts as these could deform.

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A few tips when using Milliput -

First cut off the crust on the dark green component, it does not set properly if left in.

Second leave it for about 10 minutes after mixing before using it(it is less sticky and works easier).

Third setting time is very temperature sensitive. Below 5C it takes 3-5 days, it takes about 3 hours at room temperature(15-25C) and at about 50-60C its sets in about 30 minutes. I don't recommend heating above room temperature if combined with plastic parts as these could deform.

Fantastic tips ... thank you. I didn't know about cutting the crust off or leaving it for a few minutes before mixing. I always work at room temperature and leave it for 24 hours before sanding or cutting.

Pete

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