The BIG ISS

[Retired_for_now]

By a round-about route I've committed to build an ISS for the lobby of the Pensacola Junior College Planetarium. AF Association to IPMS Club to appeal for spacecraft displays (done) to discussions on what they "really need." It's all about the ISS.

So, first thought was to build something that could be easily duplicated as a classroom project. However, it still needed to be large enough to display well hanging 10 feet in the air.

Version 1 was a test of paper wrapped PVC - kitbashing the MARS Center ISS for graphics. 3" PVC connectors are 4" in diameter so that set the scale. Building a node and the Discovery lab module brought up several problems. The PVC structure is heavy! Not the best for hanging overhead. In addition, building each module as a self-contained unit allows a variety of configurations (assuming someone is going up on the scissors lift regularly to change the model ...?). That flexibility requires everything to be glued together for installation - introducing another potential problem if I make a few bad connections. Oh, and I'd have to cobble up connections with a hole saw - not much extra room for fittings. 3" PVC is also relatively expensive - not many classrooms will be building it at $10 per module (also exceeding my "donation" limits).


Version 1

So, to version 2. Instead of PVC tubing the modules are built around 2-liter soda bottles (4.5" bore; therefore a 1:39 scale - what the hell). In addition, I drew up some simplified graphics for the module skins since the MARS Center doesn't have a complete ISS and I wasn't interested in doing all the detail work for a display hanging at least 10 feet in the air. Those are also the reasons I didn't start with Alphonso's outstanding ISS - too much detail.

Using bottles as formers was successful, joining them was not. I tried using caps rivetted back-to-back but the connections are extremely awkward. This effort has the same problems as the PVC version with self-contained modules. Also, while much lighter the connections just didn't seem solid enough for a ceiling hanger. In addition, cross connections would have to be cobbled together as well.


Version 2

Neither effort so far addressed the truss.

Thoroughly unhappy now, I punted and tried something completely different. Build a PVC armature out of 1 - 1/4 inch (3cm) tubing and skin it with paper cans (modules) and prisms (truss). Solved the weight problem - and results in a strong structure with minimal joints that should safely hang above someone's head. I can also make multiple connections using PVC fittings.

Big_ISS_Armature.pdf
Structural Support

I did some designing, then printed out some parts at half size on plain paper to verify some fit issues.


Paper Parts

Fixed a few goofs and got started. So far, it seems to be working out.



Yogi

[cdavenport]

Wow! That is an ambitious undertaking indeed.

[Retired_for_now]

The design is pretty straight forward. Modules are simple cylinders capped with a short, flat section of a right circular cone (frusta-to be precise). The ends are pierced for the PVC backbone (1.6875 inch outside tubing diameter). The cylinder is stiffened with a section from a 2 liter soda bottle (good ideas never die). Where needed (as with Columbus where the tube support terminates inside the can) there is an internal circular former with a center hole to align the backbone tube.

Columbus Module Parts


Internal stiffener


Simple Parts



As always - I'm game for any assistance from the artists out there (you know who you are!) for repaints and graphics improvements to increase the visual impact of the model. It'll be 8.5 feet (2.6m) across the truss; viewed about 10 feet (3m) overhead.

Yogi

[Retired_for_now]

Wellllll CD - It'll eat up some time, about 100 sheets of card, five or ten soda bottles, and $25 of PVC. Hoping it won't eat more than one ink cartridge (very little color except on the solar panels). Oh, and I'll eventually need some 1:40 scale enlargements of the various resupply vehicles (Soyuz, Progress, Orion, ESA ATV, Japan's new one, etc. - don't even think about a shuttle in this scale; besides, they have a 1:200 shuttle in the rocket garden I donated).

Yogi

[jagolden01]

Yogi, fine work and an incredible donation to education.

With the height it will display at, I'm not sure it calls for more detail.
Where did the model files come from, please?

Joe

[Gideon]

Wow, I would love to do this for a local school. Our local high school has an astronomy offering. I wonder if the teacher would want this model for his classroom.

How far from the cieling will the lowest part of the model be?

Also, are you sealing the paper with any sprays, etc.?

[Retired_for_now]

jag - it's original work (NASA scale drawings from NASA - Scale Model Drawing Package ) . 4.5 inch bore, pi, and Jon's cone-o-matic plus a bit of patience. I'll post the file after I get things cleaned up. You know how it goes, need to add a few parts, punch a few more holes in things, resize, etc. I am using Fortezza's (MARS Center) pressurized docking adapters suitably enlarged. I am thinking of using their Soyuz/Progress (much later!), and maybe also Ton's Orion, ESA HTV, and Alphonso's Japanese HTV as attachments. Might also just cobble up the shapes of the Soyuz/Progress (cone's & cylinders) - we'll see.

Gideon - wasn't planning on sealing it. It'll be indoors and all the stresses should be on the PVC armature. I've stored a lot of completed models in a hot, humid garage with no distortion or problems - I think because they're not sealed and the paper can breathe (and Titebond II isn't going to come loose). The lobby of the planetarium has about a 30' ceiling - so hanging 10' above the floor or higher is in order. We'll see when it's done. They want a sense of the size, so will likely hang fairly low.

Spent most of today moving a new boat for the folks (look, sniff, set up electronics, play with buttons, drive to backyard dock) so only did a little work.


Zarya

Yogi

[Gideon]

Thanks for the info. Keep those pics coming.

Do you plan to release your original work on this project for us design-impaired types?

[Retired_for_now]

Gideon - of course. And, I fully expect some of y'all to drastically re-engineer it and improve the graphics!

Yogi

[Retired_for_now]

Built up a few truss pieces (Z1 and S0) to see how that part of the structure will work. Dry fit looks OK. It should be plenty strong. I expect the biggest problem will be figuring out how to apply pressure to seat the PVC joints (final assembly) without crushing the paper skin. Might just have to make a few spares of critical parts and take them along.




Support tube is off-center to front of truss to maintain a continuous run through the S1/P1 trusses.

Still need the Zvezda service module, another node, and the normal complement of 2 Soyuz and 1 Progress to complete the spine. Then it's little boxes for the truss 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