Dalhousie's MEM

[Dalhousie]

Spurred on by greater modellers than myself, ones like Mike and Ron, here is my attempt on the Shapeways 1:72 MEM.

Upfront there were several limitations to what I could or was prepared to attempt.  Limited tools, limited experience at kit bashing, unfamiliarity with working the 3D printed material, and a general terror at spoiling such a beautiful and expensive model were big constraints.  So I basically just did a paint job, but with the option of some modifications later.  Also, I had ordered a unpolished model, so the surface was not as smooth as I would have liked.

The MEM was never built, so what aesthetic was I to use?  I wanted something that would look authentic and could be displayed on a diorama.
I initially thought of something with a LM/Skylab aesthetic, black  and aluminium panels with gold or silver foil.  But I haven’t worked with foil before and something this complex and expensive did not appeal as a first attempt.  Two other factors also came to play, the MEM would have flown almost two decades after the LM, so would have had a Space Shuttle/Spacelab aesthetic, and the martian environment is very different to the lunar one. 

The Shuttle was white overall with secondary aluminium on interior surfaces like the payload bays.  The payload bay itself was covered with thermal blankets, with metallic details.  The different Spacelabs had aluminium of white-painted panels, extensive white thermal blankets, and metallic details

I did not think foils would not work on Mars.  First of all while the MEM backshell would be generated at subsonic velocities, there would still be substantial turbulence, probably enough to rip off foil. So any thermal insulation would probably be blankets. The closest hardware timewise on the martian surface to the MEM was Viking, white with metallic details, and white thermal blankets for insulation on the tanks. 

I decided that the exterior would be white, on the advice of others here and also the appearance of the Skylab CMs, which also were spray painted matt white. The interior structure, exposed in the landing leg  bays, I sprayed aluminium. The ascent stage cabin I hand-painted aluminium and then, because it was not bright enough, the upper part I hand painted chrome.  This looked reasonably good.

I decided that the tanks, which held FLOZ-methane and the surface cabin, would have been insulated.  I could not get surgical take looking good on the tanks.  I rationalised that the ascent stage would not have had thermal blankets on the tanks anyway as it would probably have been ripped off during the ascent. Note that while Soyuz and Progress have thermal blankets, these are not exposed to a airstream until they are in a much lower ambient pressure.  So the tanks would have structural insulation.  But I hand painted the top and bottom of each tank gold, partly for contrast but also partly because both would receive a lot of reflected heat from the ascent stage cabin and the landing stage, respectively.  I also painted the landing stage tanks gold, as a coating, not a foil, just to provide visual contrast.

Surgical tape looked good on the access tunnel and the cabin.  Except for the upper part of the access tunnel, these remain on Mars, and give a great Spacelab look.  They are of course painted matt white.  I am still thinking about whether to add the black dots.  For consistency I have left a thermal blanket on the top of the access tunnel, the part that ascends to orbit.  If I don’t like this I can remote later and paint the tunnel matt white.

The recovered Skylab CMs had a lot of the structure showing through a rather beaten up white paint.  So I hand painted the sides of the landing stage aluminium and then applied a second coat of mat white paint.  I did this may making a pool of the runny matt white spray pain and then putting a cotton and  wool ball into it before dabbing the outside of the landing stage.  This looked quite nicely faded with the silver showing through.  It was not quite botchy enough so I added some irregular botches of hand-painted map white.

The heatshield I painted matt black by hand using a radial pattern.  I couldn’t find any photos of the Viking heat shield, but the MERs have a back one so I am happy with this.  While the paint was still damp I used almost try brushes of sand and dark grey paint to introduce some texture to the heat shield.  I used thin streaks of almost dry matt black round the edges to suggest a coating of heat shield material on the landing stage.

The ascent stage engine I painted bronze.  The RCS and landing engine were also bronze, but with black mixed in to suggest use. A few streaks  of almost dry matt black round the RCS suggested minor soot.

I put a hatch on the surface shelter.  This was an rectangular piece of thin card with rounded edges, carefully sized to be the same width as an Apollo LM hatch but twice the height, to make entry and exit easier.  I covered this with surgical tape, painted matt white and then put a beading of thick gold pain to suggest foil on the edges. Inconsistent but it looked good.  The hatch was glued on the left side of the surface shelter.

The ascent stage windows I painted matt black and then cut small pieces of clear plastic from a name tag to use as windows.  That was pretty much it.  I made the lower landing legs metallic titanium for contrast against the aluminium, it’s nearly noticeable.  I also used titanium for the ascent stage support structure.

The only thing I would not have done in hind sight was paint the ascent stage cabin metallic, I think flat white would have looked better.  But I am reasonably happy with it.  Thanks to everyone for suggestions, advice, and inspiration!

Further down the track I might try for RCS on the ascent stage.  While the drawings show these on booms, I don’t think this would have been practical. I will have to think of alternatives. I may also get the Airfix LM kit and use that for the RCS, ladder, antennae, and a few other details. Some I have worked out the placement. I also need the Airfix astronaut kit for a rover and astronauts doing things.

[mike robel]

nice work.  I never thought of orienting the hatch like that.  It makes a lot of sense.

I ;ile your finish.  It seems to minimize the pebbly structure of the material.

[Dalhousie]

nice work.  I never thought of orienting the hatch like that.  It makes a lot of sense.

I ;ile your finish.  It seems to minimize the pebbly structure of the material.

Thanks!

Multiple coats seemed to do it.  It was least effective on the landing leg bays and the legs, which still look quite rough.

The Apollo LM hatch was 81.28 cm X 81.28 cm.  It was wide enough but only just high enough for astronauts crawling on their hands and knees.  That was OK for the Moon, where the maximum number of EVAs was three, but not four Mars where there could have been as many as thirty.  A much higher risk ofdamage.  I just doubled the height but the ideal height might be a bit different.  The astronaut would be bent over as they backed out down the ladder, so not full height, the curve of the side also has to be allowed for.  In reality of course the hatch was on the flat end of the surface shelter, and is shown as opening inwards.  if on the side I envisage it opening rather like some aircraft doors, fist in then rotation upwards out though the hatch.  This would avoid space being taken up inside the airlock, have the mass advantages of an inward opening hatch, and avoid the risk of the wind catching a side opening one.

[mike robel]

The concept I saw had the hatch on the upper surface of the hab and swung upward.  To get out they hatch was opened and it had grab bars on the interior.  They then climbed up, then put their feet on the rungs on the hab surface, which is why my rungs and ladder are where they are.

I thnk his descent module fiuel tanks are wrong.  I think they were tilted inward and went  into the sides of the interior wall of the DM, that would give the thing enough clearance for the hatch and a small porch.  I couldn't get the angle right on my scratch built one, so I just made the tanks a little smaller.

Some  have said you can smooth the surface with acetone and similar products.  I have not tried it.

[Ronpur50]

This looks amazing!!  I love the thermal blankets on the tunnel.  And that heat shield is spectacular!  The contrast of colors of gold, white silver and black are very convincing.  I can't wait to get my small scale version.

[Dalhousie]

The concept I saw had the hatch on the upper surface of the hab and swung upward.  To get out they hatch was opened and it had grab bars on the interior.  They then climbed up, then put their feet on the rungs on the hab surface, which is why my rungs and ladder are where they are.

I thnk his descent module fiuel tanks are wrong.  I think they were tilted inward and went  into the sides of the interior wall of the DM, that would give the thing enough clearance for the hatch and a small porch.  I couldn't get the angle right on my scratch built one, so I just made the tanks a little smaller.

Some  have said you can smooth the surface with acetone and similar products.  I have not tried it.

Do you have a picture of that concept?  The only one I have (attached) shows the hatch as I have described.

Compared to that drawing, the fuel tanks are fine.  It's the surface shelter that is too long, I think, other than being a fraction too small.  If it were shorter, stopped at the access tunnel, there would be enough room for an outward opening hatch and a porch.

I didn't try acetone, it might soften the plastic I guess.  I tried sanding, but it is very hard, much harder than ordinary model plastic.

[Dalhousie]

This looks amazing!!  I love the thermal blankets on the tunnel.  And that heat shield is spectacular!  The contrast of colors of gold, white silver and black are very convincing.  I can't wait to get my small scale version.

Thanks Ron.

I really like the contrast between the beat up exterior of the descent stage and the pristine interior.

Personally I am not happy with the heat shield, although I am on the right track I think.  The advantage of the heatshield is it is meant to be rough and beat up after landing.  I might try painting radially with thinner to get the colour to run a bit, so the boundaries are more blurred.

I am wondering about a light overall patchy spray with ochre to represent martian dust.  I would hate to spoil it if it didn't work.  Maybe I will make my own dust and apply it, so it can be washed off if I don't like it.

I might paint the upper part of the landing legs white, to give a bit more contrast.  It doesn't quite look right yet.

[mike robel]

I'm looking for the drawing I mentioned.

In the drawing you attached, you can see the DM fuel tanks are angled and are cylinders topped by half spheres, not spheres as modeled.

Edit:  Here it is.  I have to admit, I never figured out what the hatch drawing was.  Crazy.

[Bob Shaw]

I'm looking for the drawing I mentioned.

In the drawing you attached, you can see the DM fuel tanks are angled and are cylinders topped by half spheres, not spheres as modeled.

Edit:  Here it is.  I have to admit, I never figured out what the hatch drawing was.  Crazy.

That illustration seems *wildly* out of scale in terms of the men/vehicle. Sort of LK vs LM...

[mike robel]

True, and not the markedly different style of Ascent Cabin and the fuel tanks.

[Dalhousie]

I'm looking for the drawing I mentioned.

In the drawing you attached, you can see the DM fuel tanks are angled and are cylinders topped by half spheres, not spheres as modeled.

Edit:  Here it is.  I have to admit, I never figured out what the hatch drawing was.  Crazy.

Thanks.  Is that from a report?  Do you have the whole thing?

My model has angled tanks with hemispherical tops.  The only spherical tanks are in the descent stage, as per the detailed drawing up put up.

A lot of the MEM artwork is not to scale, like the attached one, which shows the surface shelter as having two decks and an unpressurised garage. 

[mike robel]

Report attached

[Ronpur50]

If you are interested, here is another version of the MEM.  BTW, I ordered my 1/144th MEM Saturday.

[Robotbeat]

Nice work, Dalhousie!

Hopefully we'll see something like this built in the next 6 years in Hawthorne... I really wouldn't mind it being in Michoud or something, but NASA unfortunately has more constraints.

[Dalhousie]

If you are interested, here is another version of the MEM.  BTW, I ordered my 1/144th MEM Saturday.

Interesting combination of technologies there.  A 1968 MEM, and small atmospheric ISRU units from the 80s, and large scale solar cell mats from the 90s (the MEM used fuel cells) to power the ISRU units presumably.

[Dalhousie]

I have ordered some Shuttle decals for the MEM.

Any thoughts on placement? Are there any rules about placement of NASA logos and national insignia?

As I see it I am constrained by space, the assumption that the nationality and agency would be as visible as possible, and also assuming a desire to minimise damage to national insignia.

So a large US flag and "United States" on the surface cabin, a small US flag and "United States" on the ascent cabin on the opposite side, and the NASA worm and and spacecraft name on the sides of the descent stage. 

Any other suggestions?

[Ronpur50]

I kept mine simple, since the biggest area for markings was discarded during the descent!  Surface cabin and ascent stage are about all the area left.  And it needs to be something that will show up in surface activity photos!  You would not go all the way to Mars and not have your flag or logo in the background.

[Dalhousie]

I kept mine simple, since the biggest area for markings was discarded during the descent!  Surface cabin and ascent stage are about all the area left.  And it needs to be something that will show up in surface activity photos!  You would not go all the way to Mars and not have your flag or logo in the background.

What about the lower part of the descent stage?  The markihgs would get a bit scuffed though, which is why I thought that the worm and name would go there, leaving USA and the flag unsullied on the cabins.

[Ronpur50]

I didn't put anything there, but that was mainly because the scale of mine didn't match up. But they would get scorched but even the Orion flag got damage so obviously NASA has no problem with it.

[Dalhousie]

I didn't put anything there, but that was mainly because the scale of mine didn't match up. But they would get scorched but even the Orion flag got damage so obviously NASA has no problem with it.

Thanks!  I'll have a look at Orion.