The BIG ISS

[SAustin16]

WOW Yogi,

Excellent work, and I REALLY like how you engineered the internal structure. VERY ambitious project. Keep those pictures coming...and I hope you're having fun.

[jagolden01]

Originally Posted by Retired_for_now

... and lots of ink for the solar panels (wondering if my stash of blue and yellow paper will be enough to cheat my way through).

Yogi

Yogi, how big will each panel be? Are they all blue/gold on both sides?
If you emailed the basic outline with fold indications, could I detail them a little, print them for you and mail to you?
I can accomodate an 11" x 17" easily, 13" x 19" total.

JoeG

[Retired_for_now]

Thanks SA.

jag - the main solar panels end up 36" by 10" (slightly narrow for scale but I'm working on 8.5x11 inch paper with a 7.5x10 inch drawing field). I'm building up the panels in 6x10 inch sections - will have integral tabs for connections and a central "core" channel sized to wrap a 1/2 inch PVC tube support rod.

Big ISS_SolarPanel.pdf
PDF print of simple solar panel section (one of six for single array - eight total arrays).

Got a little more done - finished with the basic cans and the two Russian blocs but really should put a simplified Progress on the end of the spine. There's always one there for reboost. Also need at least two Soyuz "lifeboats." And, that will also require one PIRS module for the connections. And we'll need a few arms (bendy straws and some bits of paper).





You'll note I need to do some more work to reinforce the solar array installation on the Zvezda module (far left). With the PVC tube armature I can't just run a rod through the module unless I drill through the support tube also - and I don't think the positioning will be precise enough to allow that. So, working on beefing up the brackets attached to the skin.

The build is actually pretty easy - simple parts, just a fair number of them (certainly nothing like Ken's XB-70, though I am a fair bit over 100 pages to print). Bigger problem is managing the assembly. Cobbled up an assembly stand to eventually use for final assembly on site. I'll go with a 3-point stance at the aft-spine and truss ends. No permanent PVC connections yet, so I can't hang the spine from the truss. If you look at the pdf in the first post in this thread - armature - you can see the PVC elbow connecting the central node, through the Z1 truss, to the S0 truss is the critical connection that hangs the spine. Until I glue that (never do something you can't undo until you have to ...) I'll just have to work the parts separately.


I can hang just the spine up to the Destiny lab (can't connect to the forward node with my stand). I'll also be able to hang the truss as I assemble it.

Until final installation, I'll keep it in pieces. Individual spine modules and separate left and right trusses.

Yogi

[Retired_for_now]

Working mostly on the truss now (in between games). No big problems with the skins so far. However, the 8-10 foot truss has a join in the middle where a T-fitting connects it to the Z1 truss (and the spine hangs from that). I'm getting a couple inches of sag from the PVC armature over that length - and the paper boxes of the truss ain't gonna bend when this is done. I figure it'll need another eyebolt to support the truss in the middle - that'll make a four-point hang (two ends and center of truss, aft end of spine). Not a big deal.




Just about half the truss parts - missing three outer sections on each end that support the solar arrays. I'll wait a bit on assembling those parts until I figure out just how to mount the arrays. I'd like a 1-1/4 by 1/2 inch cross fitting - but all I've found so far is a T fitting. If I can't find the cross, I'll drill out the back of the T and run the solar array support straight through.

Yogi

[Retired_for_now]

Quick poll as I finish the last few design tasks.

How much interest is there in posting the parts for this (likely another big 2Mb file)?

Just parts (figure out the assembly using the NASA ISS resources) or will it need assembly instructions?

If so, do the instructions need to detail every part or just have instructions for a generic "can," truss box, and the armature?

Yogi

[Retired_for_now]

So, it swings a bit back today. More test assembly and some results. I think I'm going to mount the main solar arrays on narrow dowels or tubing rather than the 1/2 inch PVC. Should be lighter, just as stiff, easier to attach (drill small holes in main truss armature tube), and it will eliminate a couple of joins in the tubing.



Still some sag in the Zvezda arrays - and they're built wrong (wide end is outer panel) - so it'll be a redo with plain paper (lighter) to finish off the last bit-o-sag.

Cobbling up a rudimentary Soyuz shape - and figuring out how to solidly attach it is next. Won't be much detail though. Assuming no more problems that should finish off the spine for a (more or less) current ISS configuration.

Back to building truss boxes and another trip in search of dowels and brass tubing.

Yogi

Some notes on working with the PVC: joints fit tightly and only seat when "lubed" with PVC cement. You can't work the model's fit until you loosen up the PVC joints - takes too much pressure to dry assemble the PVC (you'll crush the paper parts) and if you do get it to seat fully you'll never get it apart again. So, file/sand down the ends until you get an easy fit to full depth (1-1/4") or to a mark for the final fit you want. The PVC cement will still weld the joints solid (for those you glue), it just wont be water proof (I can live with that).

[Retired_for_now]

Just about done with the interesting bits - still need to print and assemble the solar arrays, PVA radiators, and thermal radiators. Then we have to rig it for display (that should be hilarious as it will be 6 ft tall - solar arrays; 8 feet wide - truss; and 5 feet long - spine). Gonna need to sink another hook in the garage cieling.

For a quick recap (dry run for the instructions, too):
Modules are simple capped cans. Two parts glued up for the cylinder and two flat cones for the end caps. The 4.5 inch (11.4 cm) bore of the cans is sized to use a 2-liter soda bottle for either a building form or as inner reinforcement (cut an appropriate sized section of the center, parallel sided part of the bottle). That 4.5 inch bore, combined with the 175 inch diameter of actual station modules, gives us the conversion factor (0.0257) or the scale (1:39) used to convert dimensions from the NASA ISS modelers' pages.

Modules are assembled quickly by gluing up the two cylinder parts then rolling/gluing them. Form and glue the conic end caps. Bend in the tabs on the cylinder and glue on the end caps (helps to use a 2-liter bottle as a forming stand even if you don't use it as a permanent stiffener).









The modules are then threaded onto a 1-1/4 inch PVC backbone tube. Where needed, PVC junctions (T, X, elbow joints) must be inserted into the modules before they are closed up. Also, you may need to do some trimming since the fittings are (obviously) larger in diameter than the tubing.

[Retired_for_now]

More complex parts of the station are assembled like the basic modules with just a few more bits.


Major structural connections are made with the PVC fittings - inside the nodes as one would expect.


Other connections, as with the two Japanese modules, are made with a simple card/paper tube rolled to the same size as the PVC backbone (standardize the hole sizes).



The two Russian modules have a few more conic parts, some boxes stuck on, and arrays. The arrays must be surface mounted as the PVC backbone extends through the middle of everything.



The two Soyuz and one Progress are pretty simply modelled (with some test color variations ...). Progress threads onto the spine like the modules, the Soyuz must be attached to docking ports. A couple of slip-fitting cylinders, one attached to the nose of the Soyuz and one inset into each of the Russian modules, takes care of this. Not complete fidelity but it should hold them securely and be OK at the 15-20 ft expected viewing distance (see post above, it will need to have at least 10 feet of clearance from the floor to keep the barbarians from playing pinata and that puts the attachments at 13 feet, with the rigging likely to be another 10 feet above that to give reasonable attachment angles).

Yogi

[Retired_for_now]

Figured out how to do the radiators finally. Solar arrays will stand vertical, mounted in short sections of brass tubing through the main PVC tube - pretty straight forward. 3/16" (4.7mm) dowels, 36" (90cm) long fitted into 7/32" (5.6mm) tubing. They will stand up, and hang down, with no problem.

However, putting the main solar arrays vertical puts their radiator panels horizontal. Ended up gluing a paper tube on top of the truss to hold a 1/8" (3mm) dowel horizontal. The radiator base (left in picture) will be glued to the truss and the dowel socketted into the end of the radiator (right in picture) to hold it extended.


PVA radiator

Truss attachments

The main thermal radiators are supported in a similar fashion. However (using that word a lot on this project), when mounted they extend beyond the truss and so cannot be supported directly from the truss. Solution is to embed a stiff wire in the radiator base vertically (left side picture), then bend it 90 degrees horizontal out to the end of the top string of panels where there is a socket (right side of picture). An added strip of card links the ends of the three panel strings to support the entire assembly. This bit won't be mounted until final installation.


Thermal radiator

So, another test fit then some rudimentary trigonometry to get the starting sizes of the suspension lines and out to the garage for some knotting.



Yogi

[Retired_for_now]

Did some simple arms with flexible straws.


Mobile transporter/base will mount to the front of the hexagonal part of the truss - flat part glued down during final installation, long arm attached to the pentagonal face. Two additional arms to make for the Columbus and Kibo lab modules.


To secure modules on the PVC I'm using split rings at the ends - will also glue the modules together with small spots of glue and/or small card connectors. It can be disassembled if needed (hopefully never) without completely destroying the paper parts.

Yogi