Landing on top of a docking port? Will it "latch" ?

[tjsnh]

So just a general question, I figure someone must have tried this.

I've been toying with ideas on how to make ore drilling useful. Carrying the drilling rig on the ship that gets the fuel seems very counter productive, as the dead weight of the drilling equipment/refinery is going to consume more space&weight than the fuel you could carry for a tank or two taking up the same amount of space. That said, one of the ideas I came up with was to have the drilling rig base/lander with a docking port on top of it.

Then have the craft intended for refueling land gently on top of the drilling rig, with a docking port on the bottom to link up with the port on the drilling rig.

Has anyone tried this? Any anecdotes on how simple/frustrating/impossible/possible it was?

[Randazzo]

So just a general question, I figure someone must have tried this.

I've been toying with ideas on how to make ore drilling useful. Carrying the drilling rig on the ship that gets the fuel seems very counter productive, as the dead weight of the drilling equipment/refinery is going to consume more space&weight than the fuel you could carry for a tank or two taking up the same amount of space. That said, one of the ideas I came up with was to have the drilling rig base/lander with a docking port on top of it.

Then have the craft intended for refueling land gently on top of the drilling rig, with a docking port on the bottom to link up with the port on the drilling rig.

Has anyone tried this? Any anecdotes on how simple/frustrating/impossible/possible it was?

http://forum.kerbalspaceprogram.com/threads/110681-Minmus-Acres-A-Skyscraper-on-Minmus

Lunacy!

But can be done.

[Xannari Ferrows]

It works, but be ready to hit that F9 button a bit because of the wobbling it causes. Why not try a mobile platform?

[tjsnh]

It works, but be ready to hit that F9 button a bit because of the wobbling it causes. Why not try a mobile platform?

Have the platform land on the return-ship?

Hadn't considered that.

[Sharpy]

When on the ground or by the ground don't stack things vertically. Drive, claw from a side etc. You can dock too, just have enough RCS/reaction wheels to do a wheelie or stoppie in case the ports are misaligned vertically.

Or have the rig with landing legs and a docking port on top, rise to connect to the port of the fuel ship.

Landing a big thing in a gravity with precision necessary to dock is about impossible.

[FlyingPete]

Have the drilling rig on wheels, with landing legs too that will slightly lift the wheels off the ground when deployed. Mount a docking port to the top. Your return ship should have legs (made from girders etc) that will allow the drill rig to drive under it, and a docking port on the underside. When the return ship lands, drive underneath and align the docking ports. Extend the landing gear to lift the docking ports into contact and transfer the ore or fuel.

[xtoro]

I've done this before but wasted lots of fuel hovering to line up the ports. And if you land and its a little off, you have to lift off a bit and try again. Definitely try it out, its a challenge and fun, but not so much fun after a few times.

[tjsnh]

It's kindof an act of desperation. I want the drilling rig concept to be useful, but it's not efficient at all if attached to the return ship (the ship would have to be ENORMOUS for an on-board rig to be an efficient use of weight), and a horizontal linkup isn't a good option for the types of direct-assent return ship designs I'm hopeful to use this with.

[CalculusWarrior]

It's certainly possible, just insanely difficult (doing it on a low-gravity world makes things easier, though). I suggest using the Claw instead; then it doesn't matter about lining up your ships exactly, you can just hit the thing and you're fine.

[Hagen von Tronje]

Vertical surface docking procedures are about a thousand times easier and more practical by taking your pick of mods such as KAS or IR, which give you some options for moving things around. I've done both under and over docking with stock but it sucks. Docking under is subject to variable fuel mass even if you tested and aligned the ports and even accounted for the gravity of the target body, docking over is subject to everything going kablooie without rhyme or reason.

PS - Whatever you do, don't put the claw on one ship then drive another one into it, you will crash the entire game.

[Padishar]

PS - Whatever you do, don't put the claw on one ship then drive another one into it, you will crash the entire game.

Or install the latest version of Claw's Stock Bugfix Modules which includes a fix for this and various other nasty claw related bugs.

I've done some docking onto landed vessels, e.g.

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I first landed close by and then did a very careful and controlled hop on to the rover. It wasn't too difficult once I'd oriented the camera correctly so the RCS translations were going the right way. By far the hardest part was using shift and ctrl for the throttle control.

[ajburges]

[stupid mobile view deleting my posts then detecting false duplicates]

The major fuel expenditure is the lander. That determines your efficiency. Ruthlessly cut the mass from it.

I am convinced that the mass optimal transport for a mining system is the following:

>Ore lifter with dV for just ascent (minner and station refuel it for every leg) and choice of landing gear. (Large ore tanks have best dry ratio of all tanks)

> Orbital refiniery (bonus: can refine on just panels or RTG without penalty)

> Mobile minner with ISRU, fuel cells, and horizontal claw/docking port. Either have enough tanks to mine a full load at optimal site before lander rendevous or mine at landing site.

[Admac]

I've done that exact thing(Docking vertically with a landed target) to solve a base building problem on Minmus, I consider myself a pretty good pilot flying a nimble light lander, and it took me about an hour of save scumming. In hindsight it would have been a lot quicker to blow it up and fly in a whole new module from Kerbin.

My advice would be to not worry about efficiency as a mass percentage, and look at it as a tons of fuel/hour of your time. The best way to optimize for that I found was building a very large and fairly inefficient mining lander that's easy to fly and can take off with Minmus with 300+ tons of fuel. That way your whole time spent piloting refuelling missions is 30 minutes or so and you can fuel several small missions with a single landing.

Then pile on big reaction wheels and an IRSU and gigantors and lights and W/E else you think will make it easier to fly with a clean design conscience.

Edited August 5, 2015 by Admac

[Wolfox]

I´m thinking about something similar, and I might try to use some physical docking alignment support, like "V" shaped rails to lead the craft directly onto the target. Infernal Robotics may help with this...anyone did something similar before?

[ajburges]

I've done that exact thing(Docking vertically with a landed target) to solve a base building problem on Minmus, I consider myself a pretty good pilot flying a nimble light lander, and it took me about an hour of save scumming. In hindsight it would have been a lot quicker to blow it up and fly in a whole new module from Kerbin.

My advice would be to not worry about efficiency as a mass percentage, and look at it as a tons of fuel/hour of your time. The best way to optimize for that I found was building a very large and fairly inefficient mining lander that's easy to fly and can take off with Minmus with 300+ tons of fuel. That way your whole time spent piloting refuelling missions is 30 minutes or so and you can fuel several small missions with a single landing.

Then pile on big reaction wheels and an IRSU and gigantors and lights and W/E else you think will make it easier to fly with a clean design conscience.

Good point. Combining roles does reduce operational complexity. Mining operations get fuel for free so drill baby drill!

I had some unstated assumptions:

> You would keep the lander easy to fly (massive would realise some efficiency gains on its own from reduced overhead, better tanks, and more efficient, larger engines)

> You had the piloting skill to consistently land the tanker within a klick of your minner. You need to be somewhat acetate to hit the good site anyway.

Particulars of your operation may be defined by resource distribution.

My survey results came back that the optimal Minmus resource node was in a flat that needs at least 9° of inclination to fly over. An optimal launch window every 11 hours does not sound good for on demand refueling though. I can place a fuel refinery that can be rendezvoused with as normal for refueling and run Ore to that periodically. I understand that the flats make for a good spot to rocket rover so I am toying with the thought of giving my tankers landing wheels and driving to optimally placed mine heads upon landing. Using fuel cells on mine heads is a no brainer to avoid concerns about visiting the site during the night.

[Vanamonde]

Check out this guy's video, especially around the 27 minute mark.

[Superfluous J]

I just did this recently, see the video below.

Notable time stamps:

12:00 - coming in from orbit

13:10 - discussing thrust limiting (And using 2 very nice mods, neither of which are critical but both of which make it far easier)

14:30 - landed next to the base, right before actually starting the docking

16:10 - just moments from docking

[xtoro]

I´m thinking about something similar, and I might try to use some physical docking alignment support, like "V" shaped rails to lead the craft directly onto the target. Infernal Robotics may help with this...anyone did something similar before?

I'm totally trying this tonight!

[Hagen von Tronje]

I´m thinking about something similar, and I might try to use some physical docking alignment support, like "V" shaped rails to lead the craft directly onto the target. Infernal Robotics may help with this...anyone did something similar before?

I've tried it using assorted parts, both as a guide rail and to "key" the port so it would align correctly.

It can work. It can also lead to rubberband physics, parts flying off, and stuff exploding, even if you use parts with 80m/s tolerance and make contact so softly you're barely moving.

On the other hand, Infernal Robotics provides many, many possible ways to move things into position. One that worked for me is creating hydraulic suspensions using rails, which can be scaled to work on a variety of vessels with Tweak Scale. Even a tiny probe with three legs could have three miniaturized rails attached behind those legs, then all it has to do is bounce into position above the dock using RCS/torque then lower suspension until it makes contact.

[Skorpychan]

I tried the same thing in .90 for the Kethane mod.

YES, it's possible to land a ship atop another ship.

NO, that doesn't mean it's a good idea.

It's tricksy to get them aligned. You'll burn a lot of fuel. You'll destroy a lot of solar panels. You'll take ages doing so and probably tip the lower craft over.

I suggest doing it horizontally. Put your drilling rig and storage tank on wheels. Land the ascent vehicle nearby, and then drive the drilling rig into it. Either have docking ports on the side, or use the Klaw for the simple approach. This will make it infinitely easier.

There is a HUGE difference between putting a lander where you want it on a surface, and landing a 2.5m wide part of your lander exactly onto a 2.5m area on another craft, with enough force to make them snap together but not so much they bounce off or explode, while fighting gravity at the same time.

Seriously. Fighting gravity while docking is an entirely different thing from regular docking.

[xtoro]

So I came up with a cool design, pics to come. I used the I-beams to make 4 V shapes. Well, more like a Y if you split it vertically down the middle. Worked great, and just had to come down roughly on top with the right rotation. The 4 beams sticking straight out of the bottom would get guided in by the lower ship's Y brackets and settle right on the docking port.

[eonmoon]

in stock its a pain, however if you have Kerbal attachment system (KIS/KAS) you can have a kerbal attach a pipe from your drilling tanks to your spacecrafts tanks, makes things quite a bit easier, ecpecialy if your building a base and have trouble lining all these docking ports up. theres also struts that can be bolted on by your engineers too to strengthen your base

[Srpadget]

My stock-only solution for resource transfer from drilling rig to tanker ship has been a fuel rover armed with a Claw. Land the tanker somewhere near the mining base, Claw the rover to the mine's (full) tank, fill the rover, un-Claw, trundle it on over to the tanker, Claw that, transfer fuel to the tanker, un-Claw and withdraw rover to a safe distance, launch tanker.

I thought I was pretty clever.

But ... putting wheels and claw directly on the drilling rig as so many people have suggested in this thread? I totally missed the obvious solution. ::facepalm::

Edited August 9, 2015 by Srpadget
Minor spelling/grammar corrections because I'm like that