Help needed: Kethane Miner

[psyper]

Okay so I'm setting up an interplanetary miner ship which will basically do a tour around each planet system. Along the way it is set up to gather resources to keep the fuel going. I'm hoping to set up 5 of these in total to swan around the system hoping from each planet to the next.

So anyway it needs a lander which can detach from the main vessel drop down to the planet/moon mine resources (I have both Kethane and Water as resources needed to make LiquidFuel and Oxidizer respectively), and to then take these resources to the ship to be converted in to fuel and monoprop etc. The lander needs to hold enough fuel to land on each celestrial body and to lift a decent about of resources to make as least trips as possible needed to refuel the ship ready for its next intercept.

I'm planing on going to mine Moho, Gilly, Minmus, Ike, Dres, Bop & Eeloo.

I built the ship pretty much the way I wanted with a 'cartridge' system where each resource tank is a cartridge that I can use a rcs tug to move the tanks from the ship to the lander (this way if I find just a water pocket or just a kethane pocket I can load those cartridges in to the lander and not go down and back with empty tanks).

My first lander looked like this:

4 nuclear engines, 4 small drills, 5 ports so I can send 4, 2 or 1 cartridge down and remain symmetrical. I also have a hitch-hiker module to bring down crew and to plant flags if need be - also not in this picture is that it had some KAS containers with pipe equipment just in case.

Got it in to orbit attached it to my starship and sent it off to the Mun for breaking in - the ship performed pretty perfectly - once in orbit it started scanning for water and kethane and then I loaded the lander up and sent it down. Managed to land - filled all 4 tanks and couldn't lift up with the remaining fuel. I managed to get another crew down there and refuel her and managed to get her back in to orbit (JUST) and docked. I need a better solution.

So thinking that nukes don't give much extra TWR I decided to drop two of the nukes, add more fuel tanks and get rid of two drills and two cartridge bays (more trips but at least I would be able to do them this time).

So I ended up with this:

Very top heavy. Doesn't take much in the way of a hill to cause it crashing down. Also taking off is a chore but can turn pretty good and balances okay in orbit (doesn't drift while throttled up which looking at the engine arrangement i was worried it would). I have the poodle engines set to toggle if I need an extra boost - I always need an extra boost!

So I'm looking for some tips - what would you do to change the craft? What examples can I work from? I'm not looking for anyone to drop me a craft file and say use this - I want to build my own but obviously this needs some work. I need to be able to land on moho, ideally fill up 4 tanks, get back in orbit and use the least amount of fuel to do it!

Edited March 15, 2014 by psyper

[RedDevilEA]

I did something similar to this but I didn't bother with kethane tanks. I just stuck a converter and two small drills on the lander, and designed it to be able to carry four large 1.25m fuel tanks back up to the ship, in addition to the fuel needed to get up there. I connected everything with docking ports, so I could transfer fuel where I needed it, and used Mk55's for the lander. They're not as efficient as nukes, but the thrust was essential. Sometimes I had to make a couple trips to the surface and back, but it was reliable. Also, I threw solar panels and parachutes on EVERYTHING. You never know...

[Streetwind]

To avoid making your desing top-heavy, use just one of the very long kethane tanks, but on its side.

Also, to improve the terrible TWR of the LV-N's, try adding a Rockomax 48-7S or two. Map them to action groups for manual enabling/disabling, and use them just for a short burn at liftoff to build some speed. Two of them add as much thrust as another LV-N, but your vessel weight will remain basically unchanged. You don't want to have them running at all times though, so after you got that initial 10-20 second kick, disable them again with the action group and use the LV-Ns for the remaining ascent.

[Jouni]

That big RCS fuel tank adds a lot of unnecessary weight to the lander. Store RCS fuel in the mothership, and carry only the amount you are going to need with the lander.

You could use a similar engine configuration as I did in my Tylo lander. I had two nuclear engines for efficiency, and two LV-T30s for power. Most of the time, the lander uses only the nuclear engines, but when high TWR is required close to ground, the ship fires all of its engines.

[mellojoe]

Kethane tanks weight the same empty as they do full. Take this into consideration. That being said, I would flip your craft upside-down. Put the heavy fuel tanks at the bottom, and the lighter kethane tanks at the top. Use fuel lines to move things around. Secondly, consider how much delta-V you will ACTUALLY need to land and re-orbit. It might not need as large a fuel tank as you have shown. You might even consider putting on a small conversion unit to lessen the fuel requirements of the lander. Use a little fuel to land, fill up kethane, convert enough to fuel to fill up the small fuel tanks, launch and rendezvous with orbital craft.

[Kryxal]

For that matter, if the fuel tanks are closer to the ground, you can put the legs on them instead of running girders down. For RCS, you can probably reasonably downsize to 4 of the radial ones that hold 40 each, or maybe even more ... and consider using the 1*6 solar panels or just an RTG to maintain a charge, then running mining ops with the Kethane-powered generator. 4 big panels are 1.4 tons...

[Sirrobert]

Can't you use smaller Kethane tanks and a converter? Sounds like that should save alot of weight

[celem]

Whenever I build these I end up putting a small converter on the lander. For a low-grav world like minmus/gilly/bop/pol you can get away with hauling up resources to a depot and refueling each time in space. As soon as you try and lift a decent amount of these products off a stronger moon or body (mun/moho) you find that the dV required to land and then reorbit with a full load is a lot. A little converter at least lets you top off on the mining patch before filling the tanks and weighs relatively little when we are talking about hauling resources anyway. You can do it without, but it means a bigger ship.

You need to drop the nukes as much as you can. Dont risk them if a leg suspension compresses a lot, but yours are meters high and they are the major weigh source in that design as it lands (empty resource tanks, lowered fuel levels, big nukes up high). Tweak out 50% of the RCS gas and store some on whatever you are offloading to. 750 is a lot to be adding to every burn you execute, thats some 4 tonnes dead-weight, that pays for a converter right there if you halve it.

[psyper]

I did something similar to this but I didn't bother with kethane tanks. I just stuck a converter and two small drills on the lander, and designed it to be able to carry four large 1.25m fuel tanks back up to the ship, in addition to the fuel needed to get up there. I connected everything with docking ports, so I could transfer fuel where I needed it, and used Mk55's for the lander. They're not as efficient as nukes, but the thrust was essential. Sometimes I had to make a couple trips to the surface and back, but it was reliable. Also, I threw solar panels and parachutes on EVERYTHING. You never know...

The converter is out of the question really - I'm using a modified version of Kethane so I need water to make oxydizer and kethane to make liquidfuel - if I'm lucky and have two resources on top of each other or close by then I could have a converter and convert them all in one go - if im lucky of course. I also doubt I'll need the parachutes - I'm aiming for airless moons and planets at the moment.

To avoid making your desing top-heavy, use just one of the very long kethane tanks, but on its side.

Also, to improve the terrible TWR of the LV-N's, try adding a Rockomax 48-7S or two. Map them to action groups for manual enabling/disabling, and use them just for a short burn at liftoff to build some speed. Two of them add as much thrust as another LV-N, but your vessel weight will remain basically unchanged. You don't want to have them running at all times though, so after you got that initial 10-20 second kick, disable them again with the action group and use the LV-Ns for the remaining ascent.

Good point on the top heavy design - I've more or less turned the ship upside down with the kethane tanks on top and the fuel near the base - I've also got rid of the girders to reduce the height. I've swapped the poodle engines for 4 x 48-7s think that might do it and I'll add them to an action group like i did with the poodles.

That big RCS fuel tank adds a lot of unnecessary weight to the lander. Store RCS fuel in the mothership, and carry only the amount you are going to need with the lander.

You could use a similar engine configuration as I did in my Tylo lander. I had two nuclear engines for efficiency, and two LV-T30s for power. Most of the time, the lander uses only the nuclear engines, but when high TWR is required close to ground, the ship fires all of its engines.

Good point on the RCS - I found I was using about a quarter of the monoprop so I've swapped them out for radials.

Kethane tanks weight the same empty as they do full. Take this into consideration. That being said, I would flip your craft upside-down. Put the heavy fuel tanks at the bottom, and the lighter kethane tanks at the top. Use fuel lines to move things around. Secondly, consider how much delta-V you will ACTUALLY need to land and re-orbit. It might not need as large a fuel tank as you have shown. You might even consider putting on a small conversion unit to lessen the fuel requirements of the lander. Use a little fuel to land, fill up kethane, convert enough to fuel to fill up the small fuel tanks, launch and rendezvous with orbital craft.

I had no idea on the kethane tanks weight issue - that doesn't seem right to me - a bug maybe? Cant use the converter as I said above - I'm using a modified version of the kethane mod that requires two different resources to refuel the tanks.

For that matter, if the fuel tanks are closer to the ground, you can put the legs on them instead of running girders down. For RCS, you can probably reasonably downsize to 4 of the radial ones that hold 40 each, or maybe even more ... and consider using the 1*6 solar panels or just an RTG to maintain a charge, then running mining ops with the Kethane-powered generator. 4 big panels are 1.4 tons...

Legs now on the tanks , downsized the rcs to radials . Didn't occur to me that the panels were going to be so heavy - I thought I'd just stick them on for good luck. Ideally I want 4 drills to save warping time too much (I have a lot of missions ongoing and a lot of transfer windows this miner needs to keep!) but I worked out that dropping down to 2 big panels should give me enough power during the day - I can always shut down a drill or two if it gets too low. I tried to put about 12 of the 1*6's around the vessel but they either started clipping which looked odd or just looked plain silly!!

Can't you use smaller Kethane tanks and a converter? Sounds like that should save alot of weight

The tanks are normally docked to the side of the starship and a tug moves them over to the miner depending on what resource its going to pick up - a converter wont work as I need two resources to make a tank full of fuel and would either hop from one to another while on the surface or hope that the two overlap.

---

So heres my Mk III miner. I haven't had a chance to field test it so I'll report back when I do.

Without the tanks. It will dock backwards to the end of the starship so the junior docking port can be used for a kethane probe.

Up and running with the tanks on top - I even managed to make enough room underneath for a hitch-hiker can by moving the radial fuel tanks down.

Many thanks to everyones ideas - I'm still open to more suggestions and comments and it'll also help others who are in my position so its always good to get a range of solutions to the same issue!!

[psyper]

Back to the drawing board - handles very badly and no real manoeuvrability without rcs so used up most of that when landing let alone redocking with the starship afterwards! - had to get it in close using nukes and then get the tug from the ship to ferry each tank - taking an age to do it!! Also was front heavy because of the tanks - kethane does weigh extra when full - guess they fixed that bug :/

So will need a think and a redesign..

[khearn]

Try sticking on a large SAS module to give decent rotation w/o RCS.

Also, your hitchhiker module looks awfully close to the ground. If your landing legs get compressed at all, it looks like it would hit the ground (but it's hard to be sure from the picture).

I'd work on getting your resource tanks mounted lower, outside of your fuel tanks. Having them removable looks like it would make everything much more difficult, since you can't attach stuff like solar panels to them. Maybe consider having a solar panel attached to each modular tank so you don't have to have them attached to the lander?

To help get the balance right on my ships, I use the RCS Build Aid mod. It's not just for RCS, It will show you if your engine trust is off center, and how bad it is. With it I can make landers with one drill on one side, and position other gear (kethane sensors, RTGs, science stuff, etc) to balance it out.

I prefer not to use nukes on any of my landers. But my current designs are meant for Laythe and Duna, not airless bodies. I tend to use the aerospikes for their decent efficiency in and out of atmospheres. But a nuke has a much, much better ISP. We each have to live with our own self-imposed limitations.

Finally, consider how much fuel+oxy it takes to lift enough kethane/water to make fuel and oxy. If it takes 2kg of fuel+oxy to lift enough kethane+water to make only 1 kg of fuel+oxy, you're going to have a problem. It looks like Moho probably has the deepest gravity well of all the bodies you plan to land on. Make sure it will work there. I guess with the ISP of the nuke engines, that might not be as much an an issue for you, but be sure and check, before you get stuck in Moho orbit with no fuel.

[Sirrobert]

Back to the drawing board - handles very badly and no real manoeuvrability without rcs so used up most of that when landing let alone redocking with the starship afterwards! - had to get it in close using nukes and then get the tug from the ship to ferry each tank - taking an age to do it!! Also was front heavy because of the tanks - kethane does weigh extra when full - guess they fixed that bug :/

So will need a think and a redesign..

Based on the pictures, it seems like you have 1 probe core, and nothing else for control.

A probe core adds VERY little torque. Torque is how fast you can rotate a space ship. Try adding some SAS modules to the lander/miner, see if that improves things.

Also a safe bad to add some basic solar pannels to the lander, just in case you'd run out of fuel. They aren't that heavy after all

[mellojoe]

Based on the pictures, it seems like you have 1 probe core, and nothing else for control.

A probe core adds VERY little torque. Torque is how fast you can rotate a space ship. Try adding some SAS modules to the lander/miner, see if that improves things.

I'll say it a 3rd time, adding SAS or Reaction Wheels to a craft can make a WORLD of difference. In your craft, I'd stick 4 of the small reaction wheels right on top of your inline batteries. That will make a massive change in maneuverability.

I try to find ways to put 2, 3, or 4 reaction wheels on every craft I design. Sometimes I'll go so far as to turn on part-clipping and hide one inside a tank somewhere just to ensure I've got the control I want.

[psyper]

Try sticking on a large SAS module to give decent rotation w/o RCS.

Based on the pictures, it seems like you have 1 probe core, and nothing else for control.

A probe core adds VERY little torque. Torque is how fast you can rotate a space ship. Try adding some SAS modules to the lander/miner, see if that improves things

I'll say it a 3rd time, adding SAS or Reaction Wheels to a craft can make a WORLD of difference. In your craft, I'd stick 4 of the small reaction wheels right on top of your inline batteries. That will make a massive change in maneuverability.

I try to find ways to put 2, 3, or 4 reaction wheels on every craft I design. Sometimes I'll go so far as to turn on part-clipping and hide one inside a tank somewhere just to ensure I've got the control I want.

I KNOW THIS!! LOL I KNOW THIS and for some reason I totally blanked it out - even when I had trouble rotating all I kept thinking was - this thing is really bad at rotating what am I doing wrong! Even the lifter has an SAS module to help getting heavy payloads in to orbit without fighting and yet the lander has nothing so I say again I KNOW THIS *smacks head against keyboard* Thanks for pointing that out.

Also, your hitchhiker module looks awfully close to the ground. If your landing legs get compressed at all, it looks like it would hit the ground (but it's hard to be sure from the picture).

I'd work on getting your resource tanks mounted lower, outside of your fuel tanks. Having them removable looks like it would make everything much more difficult, since you can't attach stuff like solar panels to them. Maybe consider having a solar panel attached to each modular tank so you don't have to have them attached to the lander?

To help get the balance right on my ships, I use the RCS Build Aid mod. It's not just for RCS, It will show you if your engine trust is off center, and how bad it is. With it I can make landers with one drill on one side, and position other gear (kethane sensors, RTGs, science stuff, etc) to balance it out.

I prefer not to use nukes on any of my landers. But my current designs are meant for Laythe and Duna, not airless bodies. I tend to use the aerospikes for their decent efficiency in and out of atmospheres. But a nuke has a much, much better ISP. We each have to live with our own self-imposed limitations.

Finally, consider how much fuel+oxy it takes to lift enough kethane/water to make fuel and oxy. If it takes 2kg of fuel+oxy to lift enough kethane+water to make only 1 kg of fuel+oxy, you're going to have a problem. It looks like Moho probably has the deepest gravity well of all the bodies you plan to land on. Make sure it will work there. I guess with the ISP of the nuke engines, that might not be as much an an issue for you, but be sure and check, before you get stuck in Moho orbit with no fuel.

Yep you're right the hitch-hiker is pretty low down - I wanted to try and stow a hitch-hiker underneath the lander so I don't have to worry about routing ladders all over the place just so the kerbs can get off and back on with minimal RCS (I'm not sure how heavy they will be on moho so I'm thinking of the worse case scenario here. The hitch-hiker is also an optional 'cartridge' that you plug in to the bottom so it can land totally autonomous to save weight or can be used to land a crew down to plant a flag and visit any anomalies - also when they visit Ike I should have a fully fledged mining operation there for an earlier flotilla that are on their way there directly (this spaceship will be going to moho and Gilly before going to Ike so they'll get there by the time its been there awhile - hopefully the colony will still be alive and not eaten by the kraken and theres always the possibility that we need to launch a rescue mission so having a hitch-hiker is imporatant - I haven't tried landing with it stowed underneath yet but the Mark IV will be lower anyway as you suggested so I'll have to plug it in to one of the four ports along the top - not sure how that would do weight wise - may have to have two hitch-hikers to balance things out!

The removal ability of the tanks are important to the design of the ship because if I add more resources in the future (working on this as a kethane add-on at the moment) then I need to be able to bring some empty tanks to the ship in order to mine the new resources - KSC wanted to keep costs low so wanted to have a versatile lander for this - also I wanted the option to either bring two water tanks and two kethane tanks for the lucky times where I have overlapping resource fields or to bring 4 of one or 4 of the other for when I'm not so lucky! Just had a thought that I could stow a mini-converter underneath that can be plugged in for when I find overlapping resources and then have fuel tanks for the cartridges (thanks for the idea )

Looks like a cool mod - will need to look into it and if its able to work out the payload with the lifter or if I'll need to make the payload as a sub-assembly or not (theres a mod to redefine what is the root part anyway so I could install both if I need to!)

Luckily it looks like I'm getting a lot of bang for my buck in the conversion rates - I'm getting enough to refuel the lander and about an orange tank I think (I'll have to keep a closer eye on that) I think it more or less filled up my oxy on the spaceship in two trips so was pretty much the same for the liquid too. I was more concentrating on the lander itself so didn't really pay much attention to that! The big test is moho - if I can make a decent profit landing and getting off of there then we're good to go!

Also a safe bad to add some basic solar pannels to the lander, just in case you'd run out of fuel. They aren't that heavy after all

Ah yes I realised this when I deorbited and started my descent - I kept having to check my electricity to make sure I wasn't going to loose control of the ship - luckily the lack of SAS helped reduce the electrical load!! lol. Putting them on the new Mark IV!

I've also swapped out the small engines for two LV-T30's as Jouni suggested. Changed my radial fuel tanks for the squat ones and put the ports on top of them. The drills are mounted underneath and a large ASAS on top!

Mark IV docked with my fuel depot in LKO ready for its transfer to mun. I'll get better pics if its a success!

Edited March 17, 2014 by psyper

[John Crichton]

I just built my first Kethane SSTO...and here are a few tips:

1) It's more efficient to refine on the planet/moon instead of in orbit.

2) Your refinery decides how many miners you need because it's your bottleneck.

3) Less miners + smaller refinery = lighter craft (at the expense of taking longer to mine).

4) If you refine on the ground, you don't need large Kethane tanks...2-5 of the smallest ones are perfectly fine, even when using the large refinery.

5) Gigantor solar panels are the devil...way too heavy. Stick with multiple smaller ones or even better, a Kethane electricity generator to make it possible to mine in the dark.

Here's my Kethane-Plasma SSTO...not the quickest refueler out there, but it can reach all the destinations you listed without a tugger and also land pretty much everywhere but Jool, Eve and maybe Tylo (haven't tested Tylo yet).

Edited March 17, 2014 by John Crichton

[Jouni]

It's actually more efficient to carry raw kethane around and refine it only when you need fuel.

That depends a bit on the kethane tanks you are using. The 150-unit and 2000-unit kethane tanks are inefficient, as they have higher dry mass to wet mass ratios than liquid fuel tanks. The 1000-unit and 4000-unit tanks are similar to liquid fuel tanks, while the 8000-unit tanks and especially the 16000-unit tanks are more efficient.

500 units of kethane weights one tonne. With a medium converter, it can become 76.67 units of monopropellant (0.31 tonnes), 193.33 units of liquid fuel (0.97 tonnes), or 201.82 units of oxidizer (1.01 tonnes). With a heavy converter, you get 213.33 units of monopropellant (0.85 tonnes), 205.93 units of liquid fuel (1.03 tonnes), or 198.18 units of oxidizer (0.99 tonnes). When you are filling liquid fuel tanks, a medium converter transforms 1 tonne of kethane into 0.99 tonnes of fuel, while the efficiency becomes 1.01 with a heavy converter. If you use a medium converter for oxidizer and a heavy converter for liquid fuel, the mass efficiency of the refining process becomes 1.02. If you also need jet fuel, the conversion process becomes even more efficient.

[Sirrobert]

It's actually more efficient to carry raw kethane around and refine it only when you need fuel.

That depends a bit on the kethane tanks you are using. The 150-unit and 2000-unit kethane tanks are inefficient, as they have higher dry mass to wet mass ratios than liquid fuel tanks. The 1000-unit and 4000-unit tanks are similar to liquid fuel tanks, while the 8000-unit tanks and especially the 16000-unit tanks are more efficient.

500 units of kethane weights one tonne. With a medium converter, it can become 76.67 units of monopropellant (0.31 tonnes), 193.33 units of liquid fuel (0.97 tonnes), or 201.82 units of oxidizer (1.01 tonnes). With a heavy converter, you get 213.33 units of monopropellant (0.85 tonnes), 205.93 units of liquid fuel (1.03 tonnes), or 198.18 units of oxidizer (0.99 tonnes). When you are filling liquid fuel tanks, a medium converter transforms 1 tonne of kethane into 0.99 tonnes of fuel, while the efficiency becomes 1.01 with a heavy converter. If you use a medium converter for oxidizer and a heavy converter for liquid fuel, the mass efficiency of the refining process becomes 1.02. If you also need jet fuel, the conversion process becomes even more efficient.

Well, if you refine it on the ground to fill up your tanks, and than fill up th kethane tanks to fly those up to the big storage/refine station in orbit, I'd say that's the best option.

It'd be pritty heavy though, and take awhile

[John Crichton]

It's actually more efficient to carry raw kethane around and refine it only when you need fuel.

That depends a bit on the kethane tanks you are using. The 150-unit and 2000-unit kethane tanks are inefficient, as they have higher dry mass to wet mass ratios than liquid fuel tanks. The 1000-unit and 4000-unit tanks are similar to liquid fuel tanks, while the 8000-unit tanks and especially the 16000-unit tanks are more efficient.

500 units of kethane weights one tonne. With a medium converter, it can become 76.67 units of monopropellant (0.31 tonnes), 193.33 units of liquid fuel (0.97 tonnes), or 201.82 units of oxidizer (1.01 tonnes). With a heavy converter, you get 213.33 units of monopropellant (0.85 tonnes), 205.93 units of liquid fuel (1.03 tonnes), or 198.18 units of oxidizer (0.99 tonnes). When you are filling liquid fuel tanks, a medium converter transforms 1 tonne of kethane into 0.99 tonnes of fuel, while the efficiency becomes 1.01 with a heavy converter. If you use a medium converter for oxidizer and a heavy converter for liquid fuel, the mass efficiency of the refining process becomes 1.02. If you also need jet fuel, the conversion process becomes even more efficient.

All true in THEORY...but once you take into consideration fuel used to rendevous with your refinery craft in orbit, it's not really worth it imo. The margin is too slim and imo not worth the hassle.

This changes of course if you want to use 1 mining lander to refuel a whole orbital fleet with multiple other craft that don't have a Kethane mining ability.

[Jouni]

All true in THEORY...but once you take into consideration fuel used to rendevous with your refinery craft in orbit, it's not really worth it imo. The margin is too slim and imo not worth the hassle.

This changes of course if you want to use 1 mining lander to refuel a whole orbital fleet with multiple other craft that don't have a Kethane mining ability.

Rendezvous is cheap compared to hauling all the gear required for landing, kethane mining, and kethane refining with every ship. Not to mention that you would have to design all your ships with landing in mind, often adding many tonnes of landing engines that are too inefficient for transfers between planets and moons.

[Skorpychan]

Ditch the nuclear engines. They're too heavy and low thrust for a lander. Just stick a stack-mounted engine on each of the FL-T800 tanks, or a single bigger one under the center.

[psyper]

It's actually more efficient to carry raw kethane around and refine it only when you need fuel.

That depends a bit on the kethane tanks you are using. The 150-unit and 2000-unit kethane tanks are inefficient, as they have higher dry mass to wet mass ratios than liquid fuel tanks. The 1000-unit and 4000-unit tanks are similar to liquid fuel tanks, while the 8000-unit tanks and especially the 16000-unit tanks are more efficient.

500 units of kethane weights one tonne. With a medium converter, it can become 76.67 units of monopropellant (0.31 tonnes), 193.33 units of liquid fuel (0.97 tonnes), or 201.82 units of oxidizer (1.01 tonnes). With a heavy converter, you get 213.33 units of monopropellant (0.85 tonnes), 205.93 units of liquid fuel (1.03 tonnes), or 198.18 units of oxidizer (0.99 tonnes). When you are filling liquid fuel tanks, a medium converter transforms 1 tonne of kethane into 0.99 tonnes of fuel, while the efficiency becomes 1.01 with a heavy converter. If you use a medium converter for oxidizer and a heavy converter for liquid fuel, the mass efficiency of the refining process becomes 1.02. If you also need jet fuel, the conversion process becomes even more efficient.

How does this change if you needed to extract Kethane from one field for Liquidfuel and Water from another field to convert in to oxidizer? Water weighs the same and the tanks are the same as the kethane ones. If I have to make a hop from one side of a moon to another to fill up the other half of my di-mix fuel would that kick the ball firmly to the keep the refinery on the spaceship's side of the pitch so to speak!? I'm tempted to install a mini converter on my lander but its .5 tonnes that I don't really need if I have no fields that overlap with each other.

[Kryxal]

If you're going to have a spot underneath for a rescue can, why not set up so you can slot in a converter instead on an as-needed basis?

[Skorpychan]

And, indeed, why not stick a small converter on there so you can top off your tanks in situ?

[Jouni]

How does this change if you needed to extract Kethane from one field for Liquidfuel and Water from another field to convert in to oxidizer? Water weighs the same and the tanks are the same as the kethane ones.

If the conversion efficiency of water to oxidizer is the same as for kethane, then it's a bit more efficient to carry around kethane and water than fuel and oxidizer. Most of the benefit comes from using the large 8000 and 16000 unit tanks that have less dry mass than the corresponding fuel tanks. With smaller tanks, the differences in efficiency become negligible.

BTW, a natural consequence of this is that interplanetary transfer stages should use large kethane tanks and small fuel tanks instead of large fuel tanks. The larger the payload and the more delta-v is needed, the bigger the benefit.

[psyper]

I just built my first Kethane SSTO...and here are a few tips:

1) It's more efficient to refine on the planet/moon instead of in orbit.

2) Your refinery decides how many miners you need because it's your bottleneck.

3) Less miners + smaller refinery = lighter craft (at the expense of taking longer to mine).

4) If you refine on the ground, you don't need large Kethane tanks...2-5 of the smallest ones are perfectly fine, even when using the large refinery.

5) Gigantor solar panels are the devil...way too heavy. Stick with multiple smaller ones or even better, a Kethane electricity generator to make it possible to mine in the dark.

Here's my Kethane-Plasma SSTO...not the quickest refueler out there, but it can reach all the destinations you listed without a tugger and also land pretty much everywhere but Jool, Eve and maybe Tylo (haven't tested Tylo yet).

http://i.imgur.com/0LG6lSl.png

Loving the SSTO and its colours - I'm guessing the texture replacer there!! I did try to do without the gigantor panels but its finding enough surface area on the lander without either clipping the kethane/water tanks or the solar panels themselves - two gigantor's are pretty much all I needed plus some mini ones to keep the battery charged while they are stowed.

If you're going to have a spot underneath for a rescue can, why not set up so you can slot in a converter instead on an as-needed basis?

And, indeed, why not stick a small converter on there so you can top off your tanks in situ?

This is a good idea - perhaps the small converter with a sr docking port to stow underneath the lander - it needs to be a sr really because the lander sits between the spaceship and a kethane scanner satellite - I'd probably need a jr docking port and a tug to move it in to place - there is another option to add it to the top of the lander so it could have a probody and rcs so it can move itself on to the lander while in orbit...

So anyway - Lander Mk IV was pretty much a success - it landed filled up 4 water containers so thats 12,800 L of water and managed to take off with ease and docked.

A little niggle was for some reason when I first thrusted to deorbit the lander it started to spin uncontrolled - I stopped the thrust realigned to the marker and started firing again and had no problems. I checked it to make sure I didn't have any fuel lines missing or fuel unbalanced and couldn't find anything out of place. Landed okay and took off without a hitch - even was able to cut out the extra engines after the initial boost and use the nukes for the rest of the way up. When I rendezvoused with the spaceship again I kicked in the thrusters and it started spinning but this time I noticed the tanks were wobbling around so it looks like I need MOOOR STRUTS lol. Easy thing to solve with a bit of tweeking on the design. Also I had to keep an eye on the electricity level a lot so might get rid of the radial batteries and go for the large inline one. But all in all it was an easy ride and should work okay for Moho - the big test!

NEW WATER TANKS (I tried to amend the persist file with my new tanks and they ended up clipping the docking ports (still worked though without taking the rest of the spaceship with it!)

Is there not a sight more beautiful than one of your own creations screaming along after having its full of liquid

Many thanks for everyone for posting tips and hints and screenshots - you've all been a great help and I couldn't have done this without your input. I plan on posting my full spaceship in detail at the craft exchange if anyone is interested.