Circular Space Station

[mezon]

Hi!

I am trying to build a circular space station made by FL-T400 fuel tanks, Structural Fuselage and twosome inline cockpits (in a circular symmetry - eg. with equivalent elements on opposing sides of the circle). The elements are connected via normal sized docks, the core, central element is a FL-T800 fuel tank with two spokes. I attached the core element to my existing space station, added the two spokes with the starter element for the circle on the end of each spoke. After that i started attaching the parts which will form one half of the circle, but i got stuck with the last element. Ive built and tested the the whole circle as one on the launchpad and it formed a perfect loop, the unconnected dock clamped after the physics kicks in in the game. Then i dissassembled the whole thing and launched every part one by one, and assemled in orbit again with the help of small probes (monoprop + RCS + probe + klaw) and KAS/KIS. Soon i figured out, that the parts wont form a circle, because the docks are connecting in a different angle than i wanted to. I know that a clever use of subassemblies can prevent this somehow, but i've decided to use the dock rotation mod to fix it. Back to the problem: i added the last part for the half-circle, but it connects only on one end, the other dock refused to clamp. To be honest they were clipped together (i mean, that the polygons are cut into each other). Tried to rotate the part with the mod, but still clipping. Tried to make the whole station wobble, so the parts wont cut into each other at least for a second, hoping that way they will dock. No luck.

I know that a circular station can be done this way (with docking ports), my question is how to attach the last element for the circle, that has to dock on both ends? They have to dock simultaneously somehow?
Now i am at my workplace, so i have time to phrase my question =) but therefore i cannot provide screenshots yet, but i will if i get home and it is needed.

https://ibb.co/bS1Eb7
https://ibb.co/j1PgpS
https://ibb.co/icr2US
 

Edited May 4, 2018 by mezon

[Gilead]

I'm not an expert, but I think you have too much docking ports. To close the ring, you need to align all the ports perfectly. A small misalignement between 2 pieces would not mean a lot if there are not a lot of pieces. But in your case, if there's a tiny misalignement on 4 or 5 docks, that adds to a bigger misplacement at the end, big enough to not allow the last pieces to align and thus not dock to each other.

I don't know the dock rotation mod, but maybe you can rotate more precisely? If you can't be more precise, I personally would reduce the number of docking ports, by making less pieces. Instead of putting a docking port at the ends of every FL-T400, build the ring with docking ports every 3 or 4 FL-T400 instead of each one. That's my advice, but I'm not very experimented, I might be wrong. Don't hesitate to correct me if I am.

Edited May 4, 2018 by Gilead

[mezon]

Thank you for your reply!

Ok, first of all i'd like to make it clear, that i really don't want to rebuild the whole base. =) I also know that one can put entire space stations in orbit in a single launch, but i found that lame and very unrealistic.

Well, yes, less docks with more structural pieces welded together in VAB as you suggested. Welding pieces together will results in that i'll have a big arc. Which has to be placed on the top of a rocket. Definitely not across. Which makes a big offset in the center off mass. Don't know how to compensate for that... That's why i launched every piece separately.

I think i dont have a dock misalignment the way (axis) that you think. Check screenshots above.

The problem is that i have to squeeze the last piece in to complete the circle. No matter how you combine the elements, there will be a point where you have to insert a piece (with two docks on each ends) into a tight space. If the docks have to connect simultaneously, well than i have no clue how to achieve that. Although the rest of the circle is pretty flexible, so my idea was to somehow tighten the gap between the  docks and play with the undocked element until it clicks in. Dunno... Think its Kerbal's tree hierarchy problem with the two docks when they are trying to connect to the same vessel...

This mission required 16 launches, so i am open minded, even i'm willing to use a cheat to put the last piece in.

 

[Gargamel]

That sir, is what I call Kraken bait.  All those ports just add part count and induce wobble.

23 hours ago, mezon said:

i added the last part for the half-circle, but it connects only on one end, the other dock refused to clamp.

First off, the ports are connected to the same ship, so they won't dock to each other.  Ports only work on separate vessels. 

I might be wrong here, somebody might have figured a work around for this, but...  KSP ships are built in a tree.  All parts can follow a single path back the root part.   IE all parts are connected to a single part, but any single part may have many parts connect to it.   A single part may not be connected to two parts at once. 

So when you have part of the ring assembled, all the parts can trace back to the root by a single path.  But when you try to close the circle you are giving the parts 2 paths to the root.  In essence the parts of the circle are connected to each adjacent part.   KSP doesn't like this, and will refuse the connection.   Try building it in the VAB and you'll see.

Now it may have changed, back in the day this was the way it worked.  It may have changed since then, but I learned it that way, and I've always built my stations to obey this rule. 

Any time I've done a circular station like this, I build it in quarters.  So I'll have four spokes from the core, then each spoke has one quarter of the ring attached.   The last part of each quarter has a strut that connects to the next quarter.  If you position the parts very closely, you will barely see the strut.  Circular structures like this in stock, I usually build entirely on the ground, and then launch as one piece, carefully. 

(Again, noting, this is old school KSP talking, I might be outdated here...)

[Mark Kerbin]

Helllo!

Seeing as you seem to be okay with non parts mods, I have a few suggestions to help you in your endeavours.

 

 Happy Launching And May The Kraken Be With You

 

And yes it is infact possible to dock a ship with itself.

Its just really really hard and tends to cause krakening.

Edited May 5, 2018 by Mark Kerbin