Ground-based Docking

[andylaugel]

Is there a trick to docking two vehicles on the ground? I've have been able to use docking clamps on rovers to build trains and truck/trailer assemblies. I'd like to be able to dock my rovers with landed heavier vehicles. The problem I run into is that the docking ports often don't line up perfectly vertically. Even using the same wheel mountings on the level launch pad, weight often makes some vehicles ride lower than others, which makes docking difficult.

If I could do this, it might change how I run my mining operations. Currently I have a rig that lands, harvests ore, refines it into fuel, launches, docks with an orbital station, and transfers excess fuel/ore over to it. Rinse and repeat. It's a good enough system that ensures I'll always have fuel to launch again. But do I really need to spend fuel on moving the refinery, drills, and ore tanks around? A stationary mining base, with rovers to go between landed shuttles just seems to make more sense to me.

[[COxMA] Altripp]

The solution i found that works perfectly is: Use the Claw. It's got the same functionality as the docking port, and is even more versatile.

If you REALLY want to use the docking ports, then i got no advice to you, i struggled enough with this already in the past until i decided that i'd use the claw instead of the docking ports for anything that needs to dock in the ground.

[andylaugel]

Thanks! I had never used the claw before. It worked perfectly in a small scale test with a stationary fuel tank and a rover w/ claw attachment. I'll have to research it in my main campaign and put it to good use. ;)

[Rhedd]

Yep. Using docking ports on the ground is VERY tricky. Only works in perfect conditions, which rarely happens when you're on the other side of the solar system and it really matters. :P

[hamburger helper (AI assistant)]

I made a refueler that uses a claw. It's for orbit, but the claw is great for just refueling or adding other parts of a ground base. Instead of using RCS for a docking manuever, you can just crash it into the side of a rocket and refuel from there. Once done, just undock the thing.

[Empiro]

The claw works well, but remember that as of 1.0.4, you should always be controlling the craft that has the claw activated. Never back into a claw (or bad things will happen).

Alternatively, use the KAS mod and you can attach pipes and things between crafts.

[st0rmcr0vv]

I built a stock (minus mechjeb) stationary mining base. Three separate "towers"; drilling, refining, fuel storage and extra power. Linked with FLT800 fuel tanks and docking ports. Each tower set in place with a heavy duty skycrane (which doubles nicely as a tanker). I used Mechjeb to handle the docking alignment (halfway up the side of the assembly) while I managed altitude. Not elegant or pretty (and sort of "cheaty" if you're a purist) but it did the job. I will say that doing this is mildly frustrating but far less fiddling around than creating a "puzzle" base that requires rovers. This was not too terribly expensive either since all but the launch and transfer stages were used parts. Also I think that the docking ports being manually aligned in the Y axis as well helps assist the docking ports to lock in. If you're still hell bent on using the "puzzle" base and or rover idea then it might be worth your while to add some landing gear (even a few of various sizes) to the front and\or rear of your construction\refueling rover so you can manipulate the pieces up and down when trying to dock the two parts. The claw is also a good option for refuelers since you dont have to worry about having multiple docking port sizes or making sure your craft can dock with it.

[Jett Quasar]

Originally posted by Aldrigg:

The solution i found that works perfectly is: Use the Claw. It's got the same functionality as the docking port, and is even more versatile.

If you REALLY want to use the docking ports, then i got no advice to you, i struggled enough with this already in the past until i decided that i'd use the claw instead of the docking ports for anything that needs to dock in the ground.

If you don't like the claw, use aircraft tires on your modules, they don't sag under gravity like legs do.
JR

[[COxMA] Altripp]

They also don't have any torque... i tried that already, didn't work for me. Claw is the best for the job.

[Diawl]

Save a sub-assembly with a chassis of pylons and wheels with the docking parts attached to the chassis, and add the same one to the bottom of each thing you want to dock on the ground. Make sure you land on a flat surface.

[Dandyman]

Below is an older post but the concepts still work. I've built many large ground bases using ideas and setups linked in the post.
Theory thread:
http://forum.kerbalspaceprogram.com/threads/48876-The-art-of-modular-base-building

A kit the designer put together can be found below. A bit dated and I'm not sure all the rockets will actually work now. Linked more to give you more ideas.
http://forum.kerbalspaceprogram.com/threads/50685-Modular-Base-Creation-Kit

Old base using kit and some of my own stuff.
http://steamcommunity.com/sharedfiles/filedetails/?id=250002469

[El Rushbo]

Another option would be to use landing gear to shift the end of the one vehicle up or down and force the docking ports to line up, it'll be a little aggressive as they dock but it does work.

[thompsotd]

To address the problem of gravity on the suspension changing, simply eliminate the suspension by retracting the landing gear while safely on the ground. You can't do this with motorized wheels though. Or you can try lining them up in the editor rather than Kerbin because the suspension will be fully extended and closer to the gravity of the lighter bodies.

My favorite solution to aligning the vertical axis while docking on the surface is simply land on the docking port. It sounds hard but it's actually very doable, especially on Minmus!:
To do this you need a compatible base. Probably whatever you have now would actually work, as long as it's docking port isn't a junior and the docking port faces up inline with the center of mass. (If not over CoM just click "target" in the docking ports action menu while flying the craft that will dock with it.) You also need to worry about stability. You need it where the ground is flat enough (Minmus!) or the base is stable enough that the base pulse the refueling craft won't tip over.

Next you need to make the ship that will land on the docking port, refuel, then go dock with the station. In short you need a gas tank with radial engines on the side, a docking port on the bottom, a basic RCS system, and probe core or pilot with at least basic SAS. A good example for Minmus is a craft that has one of the large 1.25m tanks along with the quarter sized one. It can easily and reliably de-orbit and land with the amount of fuel it takes to fill the small tank. To carry monopropellant up add one size 1 tank and one size 0. Just like with normal fuel fill both tanks on the way up but just the small one for the way down. You should only need a fraction of the mono but accidents happen so best be safe. You won't need landing legs at all, if you need to do an emergency landing directly on the surface just be gentle. For engines use two symmetry pairs of twitches, one with thrust limiter set to max and toggled with action group, the other at third power but always on. You can radially attach OscarB's with Sparks for greater efficiency. Add an adapter at the top to put the previously mentioned size 0 mono tank, along with a reaction wheel, HECS, and a Jr. docking port for more compatibility. Of corse it needs electrical and communication systems. Add four omni-directional RCS thrusters around the CoM like you always would. This is just an example though.

Flying it is much easier than it sounds. Set up the landing like any other targeted landing. I recommend controlling from the bottom docking port for final descent. Laterally stop directly up from the base. To save mono try to get as close as reasonable by tilting the ship. In the example ship switch off the two engines with action group. Set SAS to keep the ship pointing straight up, switch to linear control, activate RCS, and carefully descend. Do to a bug on the Xbox version I have trouble with this but I recommend setting the bases docking port as target while hovering near it, especially if it is not aligned with the center of mass. After that set the throttle to approximately counteract gravity and use RCS to land on the docking port. Cut off engines right before docking.
If you have trouble with this You should probably retract anything to retract on your base before landing.
I do this all the time on Minmus and I also tested a Jumbo64 with nukes on the Mün. Easiest during the day.

Sorry for the long response. I hope this helps!

[andylaugel]

thompsotd, I made the original post 3 years and 3,000+ hours of gameplay ago. Ground-based docking hasn't been an issue for me for a long time now.

[[COxMA] Altripp]

Good ol' necrobump

[Delle(DK)]

regarding dockingports... there is a user made mission named "the martian".. in that mission you dock vehicles and attach parts to your rover via docking ports.. maybe try to find that misison and see how its made.. its a very cool but also difficult mission.
I love the part where you have a rover and then attack new parts onto it when you find them ;-)