kethane issues

[Elfomarcio]

hi guys, so i'm trying to work out a system to get kethane from mun and minmus ad taking it back to my space station orbiting over kerbin at 200km, but since now i havent been able to make it work, i tryed by having an "apollo style" craft wich separates over mun to land and take the kethane for then process it into munar orbit and then bring it back home, but other than thinking it might be a bit inefficent, i can't find a configuration that let's me get with enough fuel to take off from minmus with a full tank of kethane. the same apllies with a single stage retriever/converter, it's too heavy to take off, and it would waste too much fuel of the one i just processed to get back to kerbin wich kinda defeats the purpouse of the whole thing... so i'm asking for some help, how did u do? any suggestions on designs? thanks a lot, bye

[Kryxal]

I think it's a mistake to run your miner back and forth like that ... consider putting a second station around Minimus and maybe running fuel down to the 200km station from it while you do all the work there. After all, you're probably looking at 1000 m/s in delta-v each way between semi-low Kerbin orbit and Minimus orbit, it's a bit of a waste to make that run with any mass you don't have to.

[MarvinKitFox]

Put your kethane extractor on Mun. Move it only when needed to access a new field.

Use nuke-rocket to lift kethane to low mun orbit. (600d/v, heavy)

Return same nuke-rocket with empty kethane tanks to extractor. (600 d/v, but light ship)

This part of the cycle can be done reasonably easily, as long as you have precision landing and docking skills.

Getting the Kethane to 200km LKO.. Ion drive and patience can do it at virtually no cost.

Try to do the same thing with one vehicle that is combo lander, AND tanker, AND processor AND lifter, and your margins start shrinking. I've done it, but not efficiently! (my Kethane Gypsy could go anywhere, from anywhere, except takeoff from EVE, without losing parts or external refuelling, just its own abilities. But it needed 850tons dry mass, and it sucked a large kethane field dry in one landing)

p.s.Moving kethane is better than moving Fuel+oxy. You actually *increase* a ship's mass when converting Kethane to normal fuel.

[KerbMav]

p.s.Moving kethane is better than moving Fuel+oxy. You actually *increase* a ship's mass when converting Kethane to normal fuel.

What about the efficiency of converting Kethane to LF/OX?

If we get less then 1 ton of LF/OX from 1 ton of Kethane, we would be moving the ship more often to get the same amount of Kethane to the refinery.

[Kerba Fett]

If you want to do kethane mining I'd recommend doing it on Minmus. The objective is to get back to LKO with as much fuel as possible and Minmus allows you to burn less of it getting off the surface and leaving orbit. You should also be areobraking at kerbin to drop your AP without using fuel. Start with your PE at 45km and work your way lower with later trips till you find an altitude that drops your AP just enough to get to the altitude of your station. Then once you get to AP you just use a bit of fuel to raise your PE and you're ready to rendezvous and dock.

Also, when you build your tanker try and keep the non-fuel stuff as light as possible. No 3 man capsule just cause it looks cool. The larger probe cores work great for tankers.

Since your tanker will have a lot of mass when docking, don't skimp on the RCS. I use 2 rings of 4 quad blocks on each end of an orange tank. and either the big RCS tank or 6 of the larger radial mount tanks. This gives you plenty for docking and you still have lots left to resupply the station.

When you land your tanker on minmus you might want to deactivate the RCS ports at the bottom and leave the top ones active. When landing tall ships the RCS on the top can reduce your chances of tipping. Try to start with a kethane deposit on one of the flats to make for easier landings.

[Kryxal]

Why have a tall ship for mining? I use fuel tanks mounted radially around a central kethane tank (the 8000 capacity one). I have a few more things extending up, but there's not all that much weight there really...

[Kerba Fett]

The reason I'd go with a tall ship for a tanker is to keep the part count low. My space tanker are normally a docking port, probe core, large sas, large battery, orange tank, poodle, and some solar panels and RCS tanks and thrusters on the tank.

If I was landing on the flats of minmus I'd add some girders to the base to widen it's stance and some large landing gear.

If he's got a refueling station in LKO then it's probably got lots of parts and may have ships docked at it. Since you can only put so many parts in the same area without lagging out I prefer a low part count tanker to a high one.

Also, when you're finally docked it's more convenient to pump fuel from one tank rather than a bunch of little ones.

And you need to leave a bit of fuel in the tank to get back to minmus. Radial mounted fuel tanks take more effort to balance.

Some of this stuff seems kind of minor, but by your 20th trip you'll be happy for anything that helps even a little.

[Kryxal]

Some of the added parts are a generator and the medium converter ... basically, I land, mine kethane and convert to fuel for the run up, dock and transfer kethane out, rinse and repeat. I don't need to refuel, I use about 2/3 of the fuel getting up but the miner is a LOT lighter on descent. Still, whatever works, I suppose.

[AlamoVampire]

DISCLAIMER: Not back seat moderating, simply asking the below question:

To me, this seems like a MOD question, so, um, whys it not in the mod section? I mean, I am just askin after all