Refuelling station for dummies

[Clear Air Turbulence]

Hi there

N00b here, sandbox mode

I am having lots of fun getting to know KSP, and having landed on the Mun etc etc I am now considering some interplanetary trips. I assume I will need a space station or two, for refueling etc.

But in thinking about this, I am noticing that there are some things I do not understand. I understand that what I will need is a couple of craft some distance out, with some full fuel tanks and some ports for refueling... but how do I get the most benefit from it?

I will clearly not be able to refuel if I don't have empty tanks. Does that mean I fly up a great big ship with a ....load of empty tanks? Or that I build a ship, deplete the tanks in getting into orbit, and then refuel them once there?

And, most efficient design for refueling station. Tips will be welcome

thanks

Edited October 6, 2015 by Clear Air Turbulence

[The Aziz]

You can refuel no matter how much fuel you have in your tank. Just click on one with mod key, then on that one you want to refuel, click "in" buttons and watch how fuel flows.

[mhoram]

Regarding the placement of the refueling station, this thread contains a lot of information:

http://forum.kerbalspaceprogram.com/threads/75542

[Gooru]

A small example for an early career game is my setup for Mun and Minmus missions.

i´ve got a tourist-lander (for contracts), a science lander (for research), a transfer thug (Kerbin<>Mun and Kerbin<>Minmus), a Shuttle and a Station.

Tourists and Scientists are shuttled to the station. There they enter the lander that gets docked to the thug. The thug with lander goes to the desired moon and executes the mission. Then it returns to the station and the shuttle gets the passengers or sciencedata back to Kerbin.

The thug and the landers never return to Kerbin. They are reusable and refuel at the station.

The station has got a huge tank and sometimes i need to send a "fuel-ferry" to refill it.

[FlyingPete]

I've done something similar, only with a station at the Mun/Minmus as well. Crews get shuttled to the Kerbin station, a transfer ship brings them to either moon's orbital station, then landers based at the station go from there to the surface.

I would launch the ship with sufficient fuel on board to get to the refuelling station i.e. the tanks will be almost empty by the time you get there.

Alternatively, you could launch a ship with full tanks but not enough of them, with docking ports on the ship. You can then dock additional tanks to the main craft, and drop them as they are emptied during the mission.

[GoSlash27]

Clear Air Turbulence,

I do this:

Then this

and eventually this

Best,

-Slashy

[Clipperride]

The only time I personally launch with part filled tanks (from the VAB) is when I launched my large refuelling station. I found it easier to launch it with enough fuel to get it where I wanted it, and then sent up a couple of smaller rockets to dock with it and fill it up. That was early in my Science game when I didn't have the large engines to make launching it full easy.

One other thing to remember, if your refuelling station is in a very low orbit, you limit the degree of time warp you can use. It makes it more time consuming to dock other craft.

[SpeedDaemon]

One other thing to remember, if your refuelling station is in a very low orbit, you limit the degree of time warp you can use. It makes it more time consuming to dock other craft.

I usually go for about 130km for this reason. Also, a very low orbit doesn't give you any room under it to "catch up" when doing a rendezvous, so you're stuck waiting for it to catch up an entire orbit with you.

And Slashy's right - if you just need a (mostly) empty tank in orbit, usually the easiest way to get it there is to just strap an engine and probe core on it. Or design the boost/orbital insertion stages for the rest of your station so that they can be added as fuel storage, which is an even more elegant solution.

[Starhawk]

I am now considering some interplanetary trips. I assume I will need a space station or two, for refueling etc.

Perhaps I'm being pedantic, but it's entirely possible to go anywhere in the stock game without any space stations or refueling.

You just need to build a bigger launcher.

Happy landings!

[Red Iron Crown]

One strategy for using refueling stations with interplanetary craft: Use the IP craft's fuel to supply the lifter on the way to orbit, then refill the ship once in orbit.

[mattssheep4]

Perhaps I'm being pedantic, but it's entirely possible to go anywhere in the stock game without any space stations or refueling.

You just need to build a bigger launcher.

I have found for missions to the Mun/Minmus that this is the more efficient route.

[Red Shirt]

Perhaps I'm being pedantic, but it's entirely possible to go anywhere in the stock game without any space stations or refueling.

You just need to build a bigger launcher.

Happy landings!

This was my thinking. I've started building space stations and resource mining stations because it is more of a challenge than just building bigger single launch missions.

[Clear Air Turbulence]

I'm out at 700 km for the station and I am noticing that it's actually quite hard to rendezvous. Closest approach is about 14 km... I will need to work on my skillz.

Plus

[Starhawk]

All right. Not being pedantic this time.

I love and use my Minmus Mining Outpost and Kerbin Station (at 100 x 100 km) all the time.

Here's a shot of the station. I launched it with the axial tanks full and the radial 'arms' empty. Put a large lower stage underneath, and steered late and gently.

Docked to the station are a tanker/rover, a tug which is still strutted to the escape pods it just delivered, and the core of my Jool-5 ship.

And here's the Minmus mining outpost that makes the fuel for the station.

Happy landings!

[jiminator]

get a class e asteroid into 100km orbit. Should easily give 25 orange tanks worth of fuel

[Laie]

One strategy for using refueling stations with interplanetary craft: Use the IP craft's fuel to supply the lifter on the way to orbit, then refill the ship once in orbit.

This (or variations on this theme) is the only practical use for refueling stations I ever found. However, I'm of the opinion that this can be insanely valuable as a labor-saving design. Developing a big-S launcher to carry up a large interplanetary vessel can be a challenge all to itself. Launching an empty vessel, and/or using (part) of it's fuel during launch makes it a whole lot easier to get the thing to orbit.

Basically you're trading development time for a second (third, umpteenth) launch and some orbital maneuvering. My own preference varies with mood.

[Clear Air Turbulence]

Perhaps I'm being pedantic, but it's entirely possible to go anywhere in the stock game without any space stations or refueling.

You just need to build a bigger launcher.

Happy landings!

really? That's a downer. I wanted a reason to need space stations.

[Invader Jim]

really? That's a downer. I wanted a reason to need space stations.

I had a refueling ship docked with a science station orbiting Minmus just because I could. One day I had a ship that burned too much fuel while gathering science on the surface and it was able to get back into orbit but would never make it home. I had the refueling station rendezvous with it and then it docked, refueled and went home. You can do all you need without refueling in space but I like having a back-up in place just in case.

[eataTREE]

really? That's a downer. I wanted a reason to need space stations.

You can also install a planet pack. I recommend Outer Planets Mod, which gives you Saturn, Uranus, and Neptune-like Kerbal planets far past the orbit of Jool. I'm not sure that it's strictly impossible to visit these planets without either refuelling or using non-stock Future Engines, but I wouldn't like to try. Of course, for purposes of visiting the outer planets you would want your gas station in Duna's SOI -- Kerbin is just too close to home to matter much.

[Invader Jim]

One more thing - sometimes I create a small refueling station by accepting a satellite contract, build the satellite larger than it needs to be and include a docking port(s), and then go complete the contract and leave the satellite in orbit. Some day a ship in the vicinity may need more fuel and it is nice to be able to divert the satellite instead of creating a whole new ship to solve the problem.

[Goomblah]

really? That's a downer. I wanted a reason to need space stations.

You CAN go anywhere without refueling, but it doesn't necessarily mean you should. Generally, if the mission craft's mass in LKO is more than 40 tons, or it is reusable, I will refuel before leaving Kerbin's SOI. The larger your upper stages get, the less practical it is to launch it fully fueled, since your lifter will be growing much much larger.

[Red Iron Crown]

The larger your upper stages get, the less practical it is to launch it fully fueled, since your lifter will be growing much much larger.

Total rocket mass grows linearly with payload mass, so 2x the payload means 2x the lifter. In practice larger payloads are actually a bit better up to a point, as the larger engines are more efficient.

[Clear Air Turbulence]

I am having an odd experience with my refueller.

My design:

(1) Boosters

(2) Rendezvous unit (just a small tank, poodle, inline stabliser, solar power and remote guidance unit)

(3 ) Payload

(- stack decoupler

- beeg orange tank

- port

- fairing)

The idea is that I get into orbit, switch to drzv unit, rendezvous, dock the last stage and then decouple and jettison the RDZV unit

BUT

Quite a few times I noticed one of two things happening in the VAB

Either the Delta-V of the whole rocket goes up insanely when I add the orange tank - despite the fact that the decoupler says no crossfeed. So it considers the two stages as one stage, in spite of the decoupler. So this means that (1) I am using fuel from the orange tank (2) I have no realistic sense of the d-v on the rdzv unit

OR when I insert the stack decoupler between the 2, KER tells me I have no d-v; in other words, it does not see my assembly (rdzv unit and launcher) as a stage at all

- - - Updated - - -

You CAN go anywhere without refueling, but it doesn't necessarily mean you should. Generally, if the mission craft's mass in LKO is more than 40 tons, or it is reusable, I will refuel before leaving Kerbin's SOI. The larger your upper stages get, the less practical it is to launch it fully fueled, since your lifter will be growing much much larger.

Yes, the plan is eventually to have an interplanetary shuttle.

And after that, stations in orbit around other planets,

And landers on t'other side.

Kerbals can dream...!

Plus, I don't much like asparagus. To eat, maybe, but not on my rockets. Just an irrational prejudice. My challenge at the moment is efficient rockets. Plus I have a feeling that later versions of the game may start tightening up on the physics & that a whole lot of weird and wonderful designs may suddenly not work at all.

Edited September 29, 2015 by Clear Air Turbulence