Interplanetary Space Station

[Vingo]

I've decided that I want to build a space station around Duna. But I want to know if it would be better to build it in lko then take it to duna or take the core to duna and bring each module separately. What's more efficient/easy?

[Van Disaster]

It'd take the same energy to move it to Duna either way, taking it in pieces would mean you're expending energy taking a bunch of extra disposable parts along too. The reason not to send it in one piece is structural, so if you can stop it bending ( and thus wasting energy correcting movement ) it'll be fine. Assuming either good TWR or good burn planning so you don't waste more energy burning off-prograde, too.

Edited September 21, 2016 by Van Disaster

[Norcalplanner]

Or, depending on the size and complexity of the station, you could launch it fully assembled into LKO, top it off with a tanker if needed, then fly it to Duna. Different players have different mental pictures when they hear the word "station". Something along the lines of Skylab with the S-II or S-IV stage still attached works great for a mobile station.

[FishInferno]

What I have seen some people do, is line up all their modules in a stack, launch directly to Duna, and then assemble the station once you arrive  This can solve the issue of Flimsy Docking Port SyndromeTM

[Van Disaster]

If you've got a train of modules like that then this is one of the few times that putting your engines at the front makes a difference.

[Aegolius13]

As other folks have said, it's a tradeoff.  Build it in LKO, and will likely be very floppy (unless you reinforce with KAS struts or the like). Build it in Duna orbit, and you'll be managing a bunch injections at the same time.  This can get tricky... you definitely don't want two ships going into atmosphere at the same time.  Also, if you use aerobraking (generally a good idea), it tends to make docking a little messier. 

I'd strongly consider launching the whole thing from Kerbin in one go.  No docking, much less floppiness, and as a plus, you get to use those enormous engines that are not practical for a lot of missions.  In particular, I love the Rhino for moving space stations to the moons or nearby planets.  But this might rule out some un-aerodynamic designs, like ISS-style right-angle-fests.

[DerekL1963]

If you want to send a bunch of individual ships in one window - this guide should prove helpful.