Is it better to assemble a Jool spacecraft in orbit or do it in 1 launch.

[awsumguy76801]

So I have sent crews to Jool 2 times. 1 for a simple orbit and flybys of the moons and a second one to land on Vall. Both were launched on  a single rocket but now I'm setting my sights on Laythe and I've been having a really hard time designing a rocket that isn't too heavy and I won't have enough Delta V to transfer back to Kerbin. So I'm asking if it is more realistic and easy to assemble a spacecraft in orbit but I am worried because of my Kraken encounters while building space stations and it's gonna be 10 times worse when I'm trying to move a large wobbly craft across very big distances.

[Mahnarch]

Always send a fuel reloader a week or so ahead of time.

Make sure it's loaded up with extra stuff you'll likely forget on your main vessel - like enough solar panels, repair kits, ....(ahem) landing gear.

 

It's like sending your RV ahead to the Grand Canyon so you can drive there on your motorcycle.

[awsumguy76801]

Ok good advice

[cubinator]

Take a look at the spacecraft I assembled for my current Jool exploration.

I wouldn't have been able to put all that on a single launch, even though many of these sections could be scaled down. You don't have to put so much stuff on a ship like this as I did, and a smaller ship would require fewer fueling rockets before departing. But this gives you a sense of what is possible with orbital assembly.

You can also see that the ship is pretty long and thin, but I've never had problems with wobbling. If your spaceship is built along the main thrust axis, I think it should be pretty stable.

[Dientus]

1 hour ago, cubinator said:

You can also see that the ship is pretty long and thin, but I've never had problems with wobbling. If your spaceship is built along the main thrust axis, I think it should be pretty stable.

This is how i do my larger ships. Assemble in VAB making sure the finished product has thrust aligned with CoM.

 

Also, I use docking port SR. I have not tried to use struts to tie it all together after it's assembled in orbit (using engineers) because at one time it was buggy, but if that has been fixed then you can use those to make your craft more stable as well.

[cubinator]

1 minute ago, Dientus said:

because at one time it was buggy

I think it's still buggy.

[Zacspace]

Use autostruts to stop big orbitally assembled craft from flopping around. You can enable them in the options, I don't think they're on by default. One they're on you can even apply them or change them in flight. As for just how to use them, since I see people sometimes say their craft are even explodier with autostruts; strut things together that are as far apart as possible because the strength of the connection doesn't weaken with length. Also don't just autostrut every part, you need to leave some parts less rigid to absorb vibrations, otherwise they'll build up and shake your craft apart

[Single stage to ocean]

build a huge launcher capable of 5 kilotons and go for the prize. It is really hard to dock large stuff in orbit.

[cubinator]

1 hour ago, Single stage to ocean said:

build a huge launcher capable of 5 kilotons and go for the prize. It is really hard to dock large stuff in orbit.

DPAI mod is something I always use when doing complex assemblies like this, it helps a lot correcting for inevitable misalignments.

[Admiral Fluffy]

I don’t know how to dock, so I just launched one giant spacecraft to Jool.

V Mission discussed in this thread.

If you can dock, I recommend you do so as it seems to make launching big craft much easier.

[DeadJohn]

18 hours ago, awsumguy76801 said:

...I'm asking if it is more realistic and easy to assemble a spacecraft in orbit...

Realistic: I usually answer the "realistic" question for myself by looking at the aerodynamics of the complete ship. Something like cubinator's example ship above clearly needs to be done in multiple launches for any plausible realism.  It might be possible to exploit KSP's physics and get that into orbit in one piece, but IMO it's so wildly unrealistic that I wouldn't do that in my normal games, but possibly as a on-off experiment.

Easy: This depends on a lot of things. One big pre-assembled mission might pose extra difficulties in building and flying it into orbit, but then there's no need to dock and assemble things in orbit. Which is easier, then, depends on your personal KSP skills and weaknesses.

Some tips:

1. The 2.5m Clamp-o-tron Senior is much stronger and less wobbly than the 1.25m standard docking port. Use the Senior for the core of your station.
2. The more thrust you apply, the more wobbly your ship will be. It's sometimes necessary to spread your Kerbin escape over several orbits to avoid shaking apart weak vessels.
3. Autostruts can stabilize ships but twist them into pretzels if misused. When a docked ship wobbles too much, test turning on the autostrut only for one part at the far end of the wobble. Enable "advanced tweakables" in settings to control autostruts.
4. Do you use mods? If yes, consider "Kerbal Joint Reinforcement" (the Continued or Next forks) for less wobbling. The "Near Future" collection of mods includes additional docking ports and construction trusses.

[Jack Mcslay]

I suggest one of two approaches:

- Lander+mothership: a large, highly efficient ship with a smaller spaceplane attached to it. Take the spaceship to Jool orbit or Laythe orbit, detach the lander plane to land and return, attach back to the mothership and return to kerbin.
- Refueling outpost: send a refueling base to Bop or Pol, get the plane there, refuel, land on laythe, take off, go back to refuel and return

Either approach will need at least two launches

[big man]

While doing it all in one launch certainly is easier, I'd recommend using in orbit assembly since you are going to have to dock the lander back to the mothership anyways.