How do I make a very tall rocket more stable? Is orbital construction feasible?

[BrickedKeyboard]

I'm playing in career mode, and I've noticed that you get the maximum science when you have a bunch of laboratories and goo tanks and other things onboard your spacecraft. The problem is that the most stuff I cram in, the less stable the rocket gets. For instance, if I say : let's go to one of the inner planets with maximum fuel if I screw up.

So I'd put a pod, then a buncha laboratories and instruments, then an ion engine to get back with several stacked xenon tanks, then an ascent stage, then a lander stage (I tend to break engines landing so I need ,both), then an ion engine with more xenon to maneuver around the solar system, then a gigantic mess of liquid fuel asparagus lower stages.

The problem is this huge stack of crap wobbles back and forth during liftoff, and will fail catastrophically if I don't baby it on ascent.

I'd like to be able to mount stuff parallel to each other, and reuse the same engine to go home that I used to land. Also, it would be nice to leave most of the laboratories in orbit and land with just 1 lab and a kerbonaut.

[Franklin]

http://wiki.kerbalspaceprogram.com/wiki/EAS-4_Strut_Connector

They're the duct tape of KSP and were designed to be an anti-wobble. They have marginal mass/drag and will "detach" without fuss if you decouple pieces they're connected between. 3 from your nose to your radial rockets should add all the stability you'll need.

In terms of actual control, RCS blocks at your nose and tail, and maybe a reaction wheel anywhere in the stack to give you extra torque.

[Tank Buddy]

If you plan on using Ion engines be prepared to spend hours preforming burns.

[Sirrobert]

I would not use ion engines with such a big rocket, unles you want your burn time to be 5 hours...

Use Atomic motors instead. Still efficient, but atleast they have some thrust.

Sounds like you are overdesigning your rocket. You really don't need more than 2 science parts for a landing, that'll net you most of the science. And it's pritty easy to max out the tree as it is.

Now your question:

Yes, you can construct the rocket in orbit. Just launch the different modules up seperatly, and dock them tougether. I'd suggest you put the engines in the front though, rather than the back. This is because docking ports are not the strongest connections, and pulling the rocket will eliminate any stress put on them by wobble. (in atmosphere though, I'd push the rocket. Just works out better)

[Kasuha]

It is possible to make tall rockets less wobbly by placing struts between parts around their perimeter.

But in general in KSP it is better to build things wide than tall.

In the picture is my most successful design from career mode. It's just a no-return probe, it was doing experiments over and over again and transmitting them repeatedly to get all the science. This approach works best because you don't have to spend time sending another mission but Squad is going to nerf this approach in the next release.

Anyway, the bottom part is able to send the upper part to Duna or Eve and still have fuel left. And the upper part is able to land on a moon, perform science there and get back to orbit. I guess it'd be strong enough even to return to Kerbin. But I used it rather to carry the probe at the very top around the system to perform all the science it could reach.