Skycrane for planetary base

[0x7be]

Hello, everybody.

Although I've been playing KSP since 0.14, this is my first post on this forum

Right now I'am trying to design Kethane minig base on Minimus (and all other low-gravity planets without atmosphere).

Originally I had an idea that base modules should not have their own propulsion and should be deorbited, moved around and pulled back to orbit by special skycrane-like spacecraft. According to my plan each module should have docking port on top of it and skycrane should dock by landing "on top of" module. Unfortunately, my tests have shown that this way of mating moudle and skycrate is practically infeasible, at least for my piloting skills. Even after some practice I had less that 10% success rate with other 90% being complete disaster: either fuel ran out or skycrane crashed into module or ground.

Nevertheless, I do not want to drop the whole concept of skycrane for by base, because I do not want to pollute design of modules with propulsion systems. So, I'am asking for your help in this matter. Maybe you can suggest some tricks or mods that will help to implement this concept in a robust way.

Thank you in advance.

[korda]

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

Also, this can help you keeping ships stable after docking (or attaching hooks)

http://kerbalspaceprogram.com/quantum-strut/

[0x7be]

Thanks.

Quantum struts is great thing, I use it extensively.

Kerbal Attachment system looks very interesting, I'll try it as soon as I get to KSP

[leax256]

can you post the .craft files of the ship. I'll look into some designs for skycranes that work.

[entaran]

Basically you have two options, a top heavy spider like crane where the engines are mounted radially on 4 long struts so they burn away from your main payload (slung under the centre), angle the engines 5 degrees outwards so the centre of thrust is through the middle. These work well, but take an incredibly long time to turn with a payload attached (or use a lot of RCS or both).

The first option uses a payload attached via a docking port which you lower all the way to the surface, disconnect and fly off/establish orbit, or use the landing legs on your crane to drop down next to it (or if your'e super fast drive out from under it and drop straight down).

Second option uses a vertically mounted winch from KAS instead of the under slung docking port which gives you a LOT more freedom of movement in that you can lower your payload on a winch system to the surface increasing your margin of error quite significantly. However it's quite hard to get the winch connected to the centre of mass of the part your'e moving. I found myself attaching radial mounts to "mark" the centre, then using an EVA trip to connect the electromagnet to the centre of that giving me a correct centre of mass marker. You do most of your flight with teh winch reeled all teh way in and only extend it on the vertical descent.

[Merinsan]

As I understand it, your problem is not landing things with the sky crane, but picking them up.

I've tried this myself, and the only solution I found was to land the sky crane first, then drive the cargo underneath, and subsequently lower the sky crane. Docking while in gravity is essentially impossible. I have done it on occasion with horizontal docking, light craft and RCS. Vertical docking somehow seems harder.

[Motokid600]

Are you trying to construct a base with this sky crane? If that's the case ditch the sky crane idea. A rover crane is better. I made an awesome crane with KAS that I use to assemble modules. I'll post a pic if I can later when I'm home. But for now Google image boat cranes. That's where I got the idea from. Worked amazingly.

Best pic I could find. Imagine wheels on the bottom of each leg and a KAS winch hanging down in the center instead if the crane boom.

[Brofessional]

Who says the crane needs to fly?

[Tank Buddy]

I believe MechJeb has a hover command, Scott Manley did some kethane mining videos with the same concept. Using MechJeb would let you hover around, but the easy solution would be to just have self-propelled vehicles. Unfortunately, this is the only non-modded solution that I can think of, but is does not follow your request.

[Motokid600]

Who says the crane needs to fly?

YOU STOLE MY DESIGN!!,

.... Lol. That ones better...and bigger. But damn my crane was a lag fest. How was getting that to Duna? Mines on the mun and it was like pulling teeth... Did you have to stick it on a rocket upside-down?

[Brofessional]

YOU STOLE MY DESIGN!!,

.... Lol. That ones better...and bigger. But damn my crane was a lag fest. How was getting that to Duna? Mines on the mun and it was like pulling teeth... Did you have to stick it on a rocket upside-down?

It was a little tough getting it into LKO, I had to use the landing engines to help the NTR's finalize the orbit, but once it was there I refueled it, then refueled again at Minmus.

Landing was pretty easy thanks to the parachutes, just a puff from the landing engines to set it down gently. Nice thing about that design is that it can rotate in place like a tank.

[rdfox]

The method I'm using for assembling my Mun base is to launch the base component modules to Munar orbit, then sending a standard one-module-capacity skycrane after them, docking it to them, then docking the combined craft into the base. Once it's fully assembled, I'll use the skycranes to deorbit and land the base in one piece.