Odd Build Question

[Popestar]

So I've got a career going for the Caveman challenge, and I'm trying to think of ways (legally) to get around the 18 ton/30 part limit for spaceplanes and rockets.  I have the beginnings of a space station in orbit, and I will need to learn how to dock so I can send pods and fuel tanks and science gadgets up there, but I keep thinking there might be other ways to launch really heavy, part-intensive rockets into the cosmos.  And I came upon a thought last night that I'd like to see if the community has any input on.

I have a design that's within the limitations for the challenge that's an SSTO, but it's really pushing the edge on both parts and mass.  Which means it's not leaving much room for error or to get beyond LKO and back.  Or, well Mid-KO and back (about 200km if I push the dV).  I know that I have a lot to learn about flying without using moar boosters, so a lot of what I'm experiencing is on me.  But...there has to be another way.  And before I go about trying this, I want to see if anyone in the community has experience or advice on this idea.

I know that the VAB and SPH won't allow you to launch with craft that are over the limits for your buildings (in the Caveman challenge you are forbidden from ever upgrading your buildings).  But I'm wondering if it's possible to build multiple ships and connect them on the runway/launchpad (using docking ports) and launch?  Or, is it possible to create multiple ships and somehow move them off the runway/launchpad, then connect them via docking ports and launch them from the grass, or one of the sidewalks/streets?  My thought here is that I could create, in some order:

• Munar orbiter
• Stage to transfer from LKO to Mun
• Stage to get into LKO
• Stage to launch

That'd definitely be over 30 parts, and well over 18 tons, so I can't do it in one build.  But is it possible to build one section, move it off the launchpad, build another section, connect to the first one, and so on, until the build is done and then launch from the grass?  Or do the limits of your buildings still impact what you can/cannot launch no matter where you are launching from?  Does anyone have any experience with this?  I figured I would ask before setting off wasting time on this if it isn't viable...but if it is viable, I will definitely give it a go.

Input is appreciated!

[Mikenike]

15 minutes ago, Popestar said:

But I'm wondering if it's possible to build multiple ships and connect them on the runway/launchpad (using docking ports) and launch?  Or, is it possible to create multiple ships and somehow move them off the runway/launchpad, then connect them via docking ports and launch them from the grass, or one of the sidewalks/streets?  My thought here is that I could create, in some order:

It is possible, albeit very hard. as you need a way to raise all these parts onto one another. As long as the crafts are moved away from the runway or launchpad so you can spawn in craft, you'll be fine, the hard part is designing a system to get parts connected to each other within the part limit. 

18 minutes ago, Popestar said:

But is it possible to build one section, move it off the launchpad, build another section, connect to the first one, and so on, until the build is done and then launch from the grass?  Or do the limits of your buildings still impact what you can/cannot launch no matter where you are launching from?

Thousand percent viable, you just need to move them off the pad/runway. This will be a challenge for you, but attainable nontheless.

Check out one of Matt Lowne's videos, he uses an SSTO to make a station, but he doesn't bring the craft to the SPH after he does the first part. Stratenblitz75 also does something similar to this with a reuseable rocket design, sorry I dont have links, but the stratenblitz vid is one of his space stations I think.

[Streetwind]

It strikes me that this challenge would be a lot more fun if you waited for 1.11, and its advanced construction options

I mean, your Kerbals won't be able to lift much on the surface, but at least you can strut your docking connections after the fact to stiffen them up for launch. Also, all those 5kg parts like science instruments, antennas, basic solar panels... perfectly valid for EVA attachment in any gravity. Leaves more part budget for the bigger stuff.

 

Edited December 4, 2020 by Streetwind

[AHHans]

1 hour ago, Popestar said:

But is it possible to build one section, move it off the launchpad, build another section, connect to the first one, and so on, until the build is done and then launch from the grass?  Or do the limits of your buildings still impact what you can/cannot launch no matter where you are launching from?  Does anyone have any experience with this?

Yes. No. I don't.
(What? That wasn't enough? )

Not having actually done that, my thoughts about this are: It it probably easier to design a craft that is assembled in orbit. The largest mechanical forces that a craft is subjected to are during launch (and possible reentry, but you usually only care about a few parts during reentry), so having to deal with wobbly docking port connections is much easier in orbit than during launch.
But if you really want to assemble the craft on the ground, then I see two possibilities: have the engines to move a stage from the launchpad to the assembly place on the stage itself or spawn only the new stage on the launchpad and have a transfer vehicle that can ferry the new stage to the assembly. I would probably prefer the latter. This also sounds like a perfect case for using robotics parts from BG.
But did I mention that it is probably easier to do in orbit?

7 minutes ago, Streetwind said:

It strikes me that this challenge would be a lot more fun if you waited for 1.11, and its advanced construction options

Hmmm... Isn't that cheating? Like using a propeller powered first stage to get off Eve?
[Edit:} P.S. Did I mention that I really hate waiting for 1.11 to come out?

Edited December 4, 2020 by AHHans

[Entropian]

Do orbital assembly - gravity does weird things to docking ports and connections, and as @AHHans said, orbital craft design is far easier than a ground one.  @Geonovast did a reusable rocket where they reattached stages on the ground, but I'm not sure how many parts that took.

[bewing]

2 hours ago, Popestar said:

But I'm wondering if it's possible to build multiple ships and connect them on the runway/launchpad (using docking ports) and launch?

That's totally easy to do on the runway. Especially if all you want to do is attach an SRB stage to the bottom of a SSTO spaceplane. The runway is perfectly flat, so it's easier to do there than on the grass. You'd have to launch a piece, drive it off the runway (because the runway is locked as long as something is parked on it), launch the second piece, drive the first piece back on to the runway, dock, and then launch.

Trying to do it for a vertically launched rocket would be a huge undertaking, and probably not worth it. Moving something completely off the launchpad and then back on again sounds extremely difficult.