How to make rovers that dock every time?

[AceMgy]

I'm going nuts here. I've got a kethane mining base on the Mun, and I just completed the orbital and ground structure to finally deliver a load of processed fuel and monopropellant. I make a harrowing landing with my fuel lifter, then try to dock...

ARRRRGHHHH!!!!!

And yes, I did test it out at KSC. I even attached struts to the wheel trusses in anticipation that a full load would put the docking port lower, but apparently not enough.

I'm sick of spending so much time tweaking docking ports to make sure they dock, is there any mod that will let me get the fuel in the lifter, and/or a mod that has a docking port at a standardized height?

Edited June 22, 2013 by AceMgy

[JacaByte]

KAS will let you run fuel lines between craft, this is what I tried to use when I built a Mün base in 0.19.

[TMS]

Four options...

Variable heights using damned robotics

Quantum fuel transfer system

Kerbal attachment system

Smash **** together repeatedly until they hook up

[JacaByte]

The Quantum fuel system has a few undocumented technicalities which can be problematics; transfer nodes have to be attached to fuel tanks of the same type and you can only transfer that fuel type once that's complete. The KAS method allows you to move any and all fuel types between a pair of craft.

[AceMgy]

Smash **** together repeatedly until they hook up

Since it seems all those mods require a part put on the craft in order to work, I'll be exploring this option for a bit. Mostly to vent: this took a lot of time.

Edit: Welp...

Edited June 20, 2013 by AceMgy

[Alinor]

KAS lets you attach dock part to things using one of the green fellas.

So you can save your mission, here is what I would do -

Grab this addon - http://kerbalspaceprogram.com/0-18-2-kas-kerbal-attachment-system-v0-1/

Make small lander that you can land next to you stranded crafts.

Attach TWO axillary hosts (things that have cables) to your lander. make sure to attach nozzles to them properly and test that they can be released before launch.

Attached TWO part holders, square things where you can put parts and then retrieve them using kerbal.

Place detachable ports from KAS in to part holders.

Launch you lander to the Mun

Land within 50meters of your ships (important, length of cables is 50meters)

Get kerbal out and grab one of the detachable ports from your storage, attach to first ship.

Grab second port - attach to second ship.

Now release cables for axillary hosts and attach them to docking connectors you just placed on both ships, in dock mode.

What you should have is your two ship connected by your lander, they will be docked and act as one vessel. You can now transfer fuel and save the mission.

Edited June 21, 2013 by Alinor
Typos

[Dombi]

Here's to cheer you up!

My Private Mun>Kerbin vehicle. Actually flies back to Kerbin after refueling in the depot.

Good luck.

[SDIR]

Try putting landing legs of the same height on both the vehicle and the rover, then extend the legs on one side of the rover while driving forwards to align then. And alternative is to use several RCS blocks on one end or small engines and boost one end up or down.

[Sephta]

I wouldn't bather with a rover anyways... you have to get it up in orbit to use ist, so I went for mining landers. No hassle to dock in orbit and I can reach every Kethane deposit on the moon easily.

The only rover I had designed was a rescue vehicle - for stranded landers (I ran down one deposit and forgot - next mining op there was sucking on dry ground^^). This one had KAS on board. worked really well!

[Pulstar]

I use the KAS mod for my tanker rovers as well. It is a sane solution after all, as much as docking on the surface has the Jebediah Kerman seal of approval.

[falofonos]

Test the connection in the area around the launch site before sending them into space?

Use landing legs to land but once your mining rig has landed retract them and rest on modular girder segments as they are less likely to compress under load.

The girder is a set length and can provide attachment for your docking port jnr. I used a similar setup for my tanker design until I decided it was just easier to build the miner and tanker into one vehicle and move it to orbit when I wanted to top something up.

[Nao]

Got two unfortunately untested ideas.

Use *vertical* attachment method. You can use either landing gear or landing struts to temporarily lower one of the base modules and drive with one docking port over another, and then just rise it up. (If the module with docking port on top would stand on only 2 wheels at the rear and the one docking port in front, magnetic forces should be enough to move the thing into position without much problem).

That kind of connection would also make it possible to connect coming form any angle - something that is both important and hard to do normally.

Another idea is to use a "hose", using parts like radial decouplers and structural pylon that make connections very wobbly. The cable could adjust it's position under magnetic power of docking ports or maybe even additional RCS thrusters mounted on the docking ports themselves. (probably this would need two soft connections to make sure the docking port could move up/down left/right without rotating).

GL!

[togfox]

Just edit the persistence file. Its easy to find the fuel amount.

[MBobrik]

using stock only you have a few choices

- match not only docking ports and their heights, but also the type of wheels, and rover weight per wheel.

- calculate how much the wheel suspension will be compressed given the target planet's gravity and rover mass and offset the docking port height accordingly

- dock using landing legs, length of which is more or less independent from how much weight they are carrying

- dock vertically ( and use landing legs to either lower the top piece or raise the bottom piece )

EDIT: you could also use the idea from above, to place the docking port on something deliberately made wobbly and thus flexible, I have however zero experience with this

Edited June 21, 2013 by MBobrik

[42undead2]

The thing is also with wheels, they have this bouncy thing called suspension. At lower G, the suspension will be higher, meaning it won't fit in something with no suspension.

[AceMgy]

Thanks for the ideas guys. I've downloaded Kerbal Attachment System as that seems to be the best solution, but unfortunately I had to do a system restore for a driver issue. While that didn't affect my files, something weird happened and the next time I opened KSP, it didn't recognize my mods. So it went on a rampage deleting all ships that had a mod. I ctrl-alt-del'ed it as fast as I could, but it had already modified the persistence file, so I'm set back a good ways.

I think I might just start a new space program at this rate. Loading up my backup is too depressing seeing how much I've lost. Guess this is the Kraken's revenge for heavy mod use?

[Nao]

Great that you made it.

Since i did the test's of the hose system and it works really nice, ill post them here .

My "sure fit" attachment system. Tested under severe stress of fully loaded orange tank with kerbin gravity.

Because after connecting the craft automatically straightens out pictures were made just before successful docking. The last image shows how much not in line was the connection, as forces after docking throw the orange tank in the air.

wrong approach angle wrong height (by more than half docking port)

mixed angles and height JUMP

The 4 wheels make sure docking ports are in line, and four docking ports twist the connection so that port planes match.

[AceMgy]

Great that you made it.

I wouldn't say that considering the save-wipe.

That is an awesome system you have there for docking. But it seems a little high part-count for my tastes and I'm not sure how I would ever manage to land it on the Mun as struts would completely defeat the purpose. I'm gonna be using KAS on the next space program as it gives my Kerbals something to do, previously they were all just sitting in the habitat base while the autonomous probes docked and moved fuel around. But if I had to do it pure stock I would definitely do it like that.

[Nao]

Uhh sorry i failed at reading comprehension, RL distracted me while reading your post and somehow after i returned i thought that you managed to get it working with KAS, and proceeded with my rambling.

System restores are indeed pain to deal with. Hope you will have more luck with your next save!

One more thing about that "hose" extension system is that it also worked quite well without the fancy wheels/plates at the end and with 1 docking port instead of 4. Just the presence of couple meters of bendable part made it easier to combine at not perfect angles. (the height difference being a problem still). I will definitely use it next time i build something, it would be autonomous tug like system too.

Sorry again, and good luck.