Refuelling depot: permanent tanks, or visiting tankers?

[hoylemd]

Hey Kerbonauts!

I'm designing an LKO fuel depot for fuelling many different resuable craft, and I have a design question: Should the station have a large permanent fuel tanks(s), or should it dock semi-permanent tanker ships that are then discarded when empty? With the latter, the workflow would be like this: send up full tanker -> dock to station -> refuel many ships with it's payload -> undock tanker and return to Kerbin -> launch and dock replacement tanker.

I would still need tankers for the permanent tanks to refuel them, but I expect permanent tanks would result in a sturdier station.

What do you think?

[dryer_lint]

Hmm. I would go for permanent tanks, just to make the workflow easier... or you could always set it up on Minmus and mine for Ore

[Jarin]

^

Permanent tanks, refueling tankers from Minmus.

[RocketPilot573]

To be honest, I don't see the difference either way. A tanker sitting at the station is the same as permanent tanks. However, for lag reasons, a tanker ship is going to be many more parts than some fuel tanks (maybe ~50 versus ~10), so that tanker could make it annoying for other ships to dock, better to just dock the tanker, refuel the tanks, and get out quickly.

[hoylemd]

ooh, good point. it doesnt have to be refuelled from Kerbin. Maybe I'd have a refinery on/around minmus and just run tankers between Midway Station and Minmus

[magnemoe]

One idea is to use empty upper stages as depots as this is cheap, just add reaction wheel, probe and ports on it, rcs is also an good idea.

This fits well with mining at Minmus where you have an tanker going back and forward but as your round trip is 16 days you want an reserve in LEO.

Later on then you start sending large motherships out system an larger fuel depot would be smart, this can be combined with an transit station for kerbals, you send new crew up and take others including stranded kerbals back.

[SkyRender]

Given the weight-vs-output of ore at the moment, the most efficient option is to have the ore sitting around at wherever you want to do refueling along with an ISRU converter. Which would lend itself nicely to permanent drill-equipped miner-tankers, of course. Ore is very different from either Karbonite or Kethane in that regard.

[jarmund]

When I played around with Kethane, I started with a mining rig and a tanker-shuttle to bring the fuel to orbit to whatever needed to refuel.

However, I found it easier to just combine them into one huge vessel:

1x orange tank in the center + all the mining stuff under. Probe core and docking port on top

6x orange tanks around it, each with an LV-N, a gigantor panel, lights and landing legs. I had some radially attached helper engines as the TWR was slightly under 1. This was on Minimus, by the way.

It did the job perfectly, and was my pride for that savegame. I just had to:

1) Make sure it was balanced. I used TAC Fuel balancer for that

2) leave the center tank half full after refueling, so that it could get down to the surface safely.

[K3RBAL KOL4]

IMHO.. Just build with Docking Ports. This way they can be permanent or undockable. No need to tie yourself down with permanence.

[Aerindel]

When I played around with Kethane, I started with a mining rig and a tanker-shuttle to bring the fuel to orbit to whatever needed to refuel.

However, I found it easier to just combine them into one huge vessel:

1x orange tank in the center + all the mining stuff under. Probe core and docking port on top

6x orange tanks around it, each with an LV-N, a gigantor panel, lights and landing legs. I had some radially attached helper engines as the TWR was slightly under 1. This was on Minimus, by the way.

It did the job perfectly, and was my pride for that savegame. I just had to:

1) Make sure it was balanced. I used TAC Fuel balancer for that

2) leave the center tank half full after refueling, so that it could get down to the surface safely.

Exactly what I did. It seems its always easier to make a ship that refuels itself than to use a separate tanker miner. Too bad as fueling stations would be fun but ISRU is so light and small you may as well just stick it on your favorite ship and be done.

[Norcalplanner]

Permanent tanks, combined with KJR, allows you to optimize your station for part count. A highly serviceable station/depot can be made with fewer than 25 parts.

[Violent Jeb]

Without KAS, i'm building my Mining vessel so that it can drill and launch itself into orbit.

Surface docking is infinitely more challenging, so i'd rather keep the functionality.

Rig will go down to minmus, drill and fill tanks, then re-enter the orbit to serve as the refuel station until it needs to re-land and re-fuel

[Xaver]

That depends on how often you refuel ships at your station. In lko like you say you will dock often and so the refueling tankers is the obvisiouly choise becouse else you have to refill your fuel depots often with tankers, what has the same effect at the end. But you have to consinder that you may want to refill a very large craft and maybe one tanker is not enough. So your fuel backup at your station should be big enough.

Edited May 6, 2015 by Xaver

[Aerindel]

Surface docking is infinitely more challenging, so i'd rather keep the functionality.

Not if you use the claw on a fuel truck. Its very easy that way.

[problemecium]

Honestly I recommend both. Have some permanent tanks there so you'll always have a fuel reserve available, and use tankers for day-to-day upkeep and whenever you need a capacity boost.

[Galileo Kerbonaut]

I use permanent tanks so whenever something is in LKO and still has a lot of fuel in it (e.g. a failed test craft) can dump its fuel in the station before landing.

[merendel]

I usualy send up a cluster of 7 orange tanks (1 core with 6 radialy attached) and just dock it to whatever I'm useing as a station core. Thats normaly plenty of fuel to refuel several missions baring some ginormous grand tour mothership. At only 9 parts (with a docking port on either end) it has minimul impact on the lag for the station. My tankers tend to have quite a few more parts than that so they are only for delivering fuel to the station to top it off or rarely to deliver fuel to a stranded ship.

[Sirrobert]

It is WAY cheaper/easier to ferry fuel from Minmus/Mun than from Kerbin

[Axder]

I am planing to capture a few asterodis, put them in Low Kerbin orbit and use them as refueling station. The first investment will be higher than landing on minimus, but later it should be easier with fact than no inclination burns and overall easier acces. But there is also my Plan is to create a Ship than can go anywhere exept eve which refuel betwen missons on Low kerbin orbit and crew and experimnts will be carried down wit SSTOs .... so i will have a nice space program that cost prety much zero funds to run.

[jdmgto]

In my experience I could never keep a stationary fuel depot low enough in part count to not grind everything to a halt when I needed to use it. My Kethane architecture was a surface mining outpost -> Orbital tanker -> Fuel barge. The Fuel barge would then go where it was needed in whatever system it was in be it Kerbin, Duna, Jool, whatever.

[StormKat]

Why not both?

[Valley]

I have fuel trailers. They can be docked in with a station. Once full they can be attached to a tug/space craft. When not needed I can just place them in a orbit to pick up later. Or they can be placed in orbit to act as small fueling stations.