Difference between revisions of "Tutorial:Rocket Assembly"

Revision as of 05:37, 2 July 2014

Most people use sub-assemblies for commonly used part-groups like boosters, but they can do so much more. The trick is to place an arbitrary and unneeded part as the first part when building a module intended to be used as a sub-assembly(it doesn't have to be a probe core, it can be anything that can be placed as the first piece). Once the module is complete, pick up the piece you intend to attach to whatever ship you are building later, and drag the whole thing to the sub-assembly window.

I recommend using an info mod like kerbal engineer or mechjeb to allow you to see important stats like weight. If you design each module to meet an exact weight requirement, let's say 5 tons, then you can place those modules on your new vessel in a radial pattern without having to worry about center of balance being thrown off. You can add ballast to modules to achieve the necessary weight. You could have a 5-ton rover module, a 5-ton lander module, and a 5-ton satellite module (probably with several satellites).

As you can see, this allows for greater diversity while building your main vessel without having to rebuild each item every time. Creating a variety of modules at different weights should allow you to build ships for just about any occasion at your whim. You can also use sub-assemblies to save entire stages to make the whole process even faster. Create a launch stage using a test payload of a given weight, and try to get into orbit. If it works, you can save that launch stage as a ##-ton launch stage. Eventually, you may be able to build all of your ships almost entirely through sub-assemblies.

• 

  Place the first arbitrary piece. Note it's weight if you plan on balancing modules. I used the stack separator to show me the weight of only the pieces after the arbitrary piece.

• 

  Build your module.

• 

  Detach the module by grabbing everything that you plan to mount on the vessel later. The green attachment point will be the point where it attaches to the rocket.

• 

  If you plan on being able to attach modules in a radial fashion, weight balance will be very important. You can attach other things to your module to help change it's weight. Using fuel as ballast is generally the best way to go, as you can usually use the fuel. If you do use some sort of ballast to get your module's weight exact, be sure to also include a decoupler so you can separate your module from the ballast.

• 

  Although the location of the center of mass will change the amount of torque applied at the attachment point, as long as the weight is counterbalanced when attached to the rocket the location of the module's center of mass will not affect the location of the rocket's center of mass.

• 

  Here I'm using a small RCS tank for ballast, as I didn't need much weight. This landing/return module weighs 8 metric tons.

• 

  Your attachment points on your rocket should have some means of disconnecting the payload modules unless they are self-disconnecting.

• 

  Here I have attached the 8-ton lander/return unit on one side, and an 8-ton rover on the other (I had to use quite a bit of ballast). Ideally I would have used a heavier module opposite the lander and required less ballast, then placed the rover on top.

• 

  checking center of mass for launch stage...

• 

  ...and checking center of mass for orbital stage.

• 

  Secure those payloads with struts or they'll wobble... a lot.