Adding Craft to Payloader / Best way ?

[Psykikk]

Hi there

I am trying to figure out the most efficient and fastest way to assemble multi-launch missions. 

meaning: same  payload vessel, switching payload. 
I know I can build each final stage, then plug a subassembly under it and be done. 

 

BUT: what about switching payloads of fairings ?  how would I accomplish this ? 
to I really need to reaasemble the payload stage each time ? this seems tedious, especially since some payloads are fully operational craft that are saved individually anyways. 
like probes / satellites etc. 

isn´t there an effective way to attach several craft to one payload ?
could anyone ELI5 or point me towards a good / decent tutorial on how to do this ? 

my vision / idea would be - like many others do - just build one delivery payloader which gets switched out according to payload mass, (or desired deltaV) and then put payload in. 

thanks in advance. 

[jimmymcgoochie]

So you’re trying to create a standardised set of launch rockets and upper stages to reuse for different missions? The best way I know to do that is to use dummy payloads- ore is especially good as it’s very heavy and dense, requiring only a few ore tanks to get the required payload mass, and also dirt cheap; fuel tanks with locked feeds so they can’t be drained are the next best option.

Build your dummy payload to the required mass and then build an upper stage (or stages) that give you the required delta-V for what you’re doing with it (Kerbin orbit, Mun/Minmus orbit, interplanetary transfers are more variable but a delta-V map will give you a good ballpark number to work with). Re-root the vessel to the decoupler that the payload will be attached to on the upper stage, remove the payload and save the vessel.

Then create another dummy payload that’s as heavy as your new upper stage and payload combined and build a launch rocket that can put that into orbit. Remove the upper stage and save that too.

Repeat until you have a selection of different upper stages and launch rockets for different payload masses and destinations as needed.

Keep in mind that adding more fuel to an upper stage will reduce the delta-V of every stage below it and that reducing the payload mass even slightly can reap big increases in overall delta-V- and conversely making things heavier will reduce delta-V pretty significantly. Always include a little extra delta-V to make up for losses due to drag, course corrections and especially for long burns which are often not perfectly pro/retrograde and so lose a bit of delta-V through cosine losses as a result.

 

[Psykikk]

thank you but maybe I was no clear enough abot what I am trying to accomplish: 

the launcher is easy as it can be saved as sub-assembly.  so building different launchers acording to deltaV needed works exactly as you stated.  dummy weights (which I did) and off you go. 

BUT what I am trying to do is have a launcher, then attach several fully fledged , indivicual craft as payloads. 
example: a launcher that delivers several satellites to one planet (for relay constellation setup ). 

what I did so far is build one satellite, attach the launcher, then copy / paste what I could from the one satellite to add the additional ones. this still took quiet some time, even though all three satellites ended up being exactly the same. 

but what about if I wanted to deliver a satellite (which is craft A, assembled and saved), a rover (craft B, assembled and saved) plus a skycrane (craft c)
in one go. ? 

so the order of assembly is just different: choose target and weight, grab launcher. then add payload. 
but it seems the only way is grab payload, then grab launcher. 

in reality thats not how it works. payloads ar designed for launch capacity, not the other way round.
at least afaik


as an example: I have this ISUR Unit. its a fully saved VAB craft. how would I load (attach) two of those to one launcher ?

 

Edited December 7, 2022 by Psykikk
example pic

[TheFlyingKerman]

Save a copy of your payload to another file, with root part re-rooted to the part attaching to the rocket. Close and open your main craft. Then open the other payload, but choose 'Merge' in the load menu. Then the payload would be loaded like a sub-assembly. Indeed I only use this merge function.