Circular habitats

[Atlas2342]

So, I want to build an Elysium-esque space habitat. I want to ask, how do you build them? 

Many thanks.......

[Snark]

3 minutes ago, Atlas2342 said:

So, I want to build an Elysium-esque space habitat. I want to ask, how do you build them? 

Many thanks.......

So, a few things you're going to run up against.

First, rotation is not persistent.  You can set it rotating, but every time you enter timewarp, or switch to another ship and come back, it's going to be stopped again.  So be aware of that.

You can't build a closed loop of parts in KSP, due to the "tree" structure of rockets.  So you're going to have to use struts to close the loop.

It's going to be incredibly un-aerodynamic, so expect a challenge getting it launched.  Doesn't mean impossible, just means you're going to have a very wacky contraption to get that thing out of the atmosphere. 

I've never tried building such a thing myself, but have seen someone posting screenshots in this forum before.  What they did was have a central spindle, and then four "arms" extending radially outward, using the long skinny 4-ton fuel tanks.  The circular rim consisted of a bunch of Mk2 passenger cabins string end-to-end with their dorsal surfaces facing radially inward, with a slight angle between each pair of cabins.  Closing the loop required struts.

[ineon]

I built a docking ring for my space station which doesn't look too dissimilar to what you want to achieve. If I remember I will post some pictures (but don't hold your breath). Try googling for "Kerbal Docking Ring" and you should find some tutorials on building a ring like structure.

I ran into the closed loop problem that Snark mentions, and ended up clipping the loop parts into each other to give it some semblance of closed-ness. I also strutted the parts together. 

41 minutes ago, Snark said:

It's going to be incredibly un-aerodynamic, so expect a challenge getting it launched

I completely agree with this. I think I put in about 5000m/s dV into my rocket to get it out of the atmosphere. It had some of that left over once it got to orbit, but not loads. It also really wanted to fly backwards.

The other lesser problem that I found is that loops will tend to be high in part count. To get the angle looking smooth you need lots of little pieces. My PC is a little old, but there is a noticeable pause whenever any ship approaches the station.

The alternative approach that I have seen (but not done myself) is to construct the ring in orbit. A simple(ish) setup might involve 24 structural fuselages with a docking port on one end of each and a docking port rotated by 15 degrees (24 * 15 deg = 360 deg) on the other. You will need a few tugs on the launch vehicle and probably some extra docking ports on some of the parts to help close the link. This approach will require fewer struts and might also be less draggy on take-off. However I think that it will be very fiddly to construct in space.

Edited December 18, 2015 by ineon