Fuel space station

[Chik Sneadlov]

Maybe I'm naive. I assumed that I could build a ship, launch it into orbit around Kerbin, leaving a huge tank of fuel circling the globe and then build another ship and launch that so that it rendevoused with the fuel tank in orbit and transfer the fuel from the one tank to the other or dock with the full fuel tank. When I built the second ship and launched I found that my orbiting fuel tank was gone or at least not showing on the map.

What is the correct way to do this? I want to build a refueling station in orbit and maybe another one in orbit around the Mun and then visit those stations with other rockets in the future. And if I can do this do I have to dock the empty tank with the fuel tank in order to transfer fuel or is it enough to pull along side?

Are fuel stations even necessary for long range journeys?

Another question involves tall rockets tilting way off vertical and falling apart. Do I need something besides ASAS to keep my tall rockets vertical?

[electronicfox]

Maybe I'm naive. I assumed that I could build a ship, launch it into orbit around Kerbin, leaving a huge tank of fuel circling the globe and then build another ship and launch that so that it rendevoused with the fuel tank in orbit and transfer the fuel from the one tank to the other or dock with the full fuel tank. When I built the second ship and launched I found that my orbiting fuel tank was gone or at least not showing on the map.

What is the correct way to do this? I want to build a refueling station in orbit and maybe another one in orbit around the Mun and then visit those stations with other rockets in the future. And if I can do this do I have to dock the empty tank with the fuel tank in order to transfer fuel or is it enough to pull along side?

Are fuel stations even necessary for long range journeys?

Another question involves tall rockets tilting way off vertical and falling apart. Do I need something besides ASAS to keep my tall rockets vertical?

Put a probe core on the ejected fuel tank. Anything without a command part is assumed to be debris, and will vanish. You will need to dock to transfer fuel.

Put some control surfaces around the top and bottom of your rockets, also some struts.

Edited November 12, 2014 by electronicfox

[Slam_Jones]

If you aren't too skilled at docking yet (not many are) you can put a claw unit on a ship, latch onto the tank, and transfer fuel that way. Doesn't require the precision of regular docking, but not recommended for building large stations.

[electronicfox]

KAS is also a good mod for this. Just pull up beside the fuel tank, attach a fuel line and bobs yer uncle.

[Torquemadus]

When I built the second ship and launched I found that my orbiting fuel tank was gone or at least not showing on the map.

The tank is probably still there. Debris is not shown in the tracking centre by default.

[Spatzimaus]

Put a probe core on the ejected fuel tank. Anything without a command part is assumed to be debris, and will vanish. You will need to dock to transfer fuel.

Also note that without a probe core (and SAS, and batteries, and solar panels) that fuel tank will be tumbling randomly, with no way to keep itself stable. That'll make docking much more difficult if you're trying to dock with ports instead of using a claw or KAS lines.

In general, I've found that it's best to make your fuel depots as fully functional vessels that just happen to be carrying more fuel than they need. Small but efficient engines will allow you to put that depot in the orbit you want (or fly them to another planet), strategically placed lights make docking a bit easier, etc. Just keep the part count low enough that the sum of the part counts for the two vessels involved in a docking is below what your computer can handle.

[lordlundar]

KAS is also a good mod for this. Just pull up beside the fuel tank, attach a fuel line and bobs yer uncle.

There's a catch 22 with that. The fuel line tends to be considered FAR more rigid than (in my opinion) it should be. If you have ships that have some minor stability issues they are exaggerated considerably and can cause a rather impressive Kessler Syndrome effect.

[John FX]

I made a tutorial on building a refuelling station (it refuels itself using Karbonite).

It is made for use with FAR and DRE so some craft may be low on Dv in stock. You may get some ideas from looking at it though.

http://forum.kerbalspaceprogram.com/threads/97475-Standard-Utility-Construction-Kit

You end up with this at the end

Edited November 13, 2014 by John FX

[LaytheAerospace]

KAS + Infernal Robotics == Crazy awesome space stations. Check the link in my sig for my spacedock.

[LethalDose]

Maybe I'm naive. I assumed that I could build a ship, launch it into orbit around Kerbin, leaving a huge tank of fuel circling the globe and then build another ship and launch that so that it rendevoused with the fuel tank in orbit and transfer the fuel from the one tank to the other or dock with the full fuel tank. When I built the second ship and launched I found that my orbiting fuel tank was gone or at least not showing on the map.

What is the correct way to do this? I want to build a refueling station in orbit and maybe another one in orbit around the Mun and then visit those stations with other rockets in the future. And if I can do this do I have to dock the empty tank with the fuel tank in order to transfer fuel or is it enough to pull along side?

Are fuel stations even necessary for long range journeys?

If debris is in a stable orbit, it will stay in the game unless you click "terminate" from the tracking station or you have limited the amount of persistent debris in settings. A "stable orbit" around Kerbin is an with a PE above 22km. When inactive vessels pass below this they will be removed/deleted, whether they have probe cores, capsules, or no control ("inactive" means not actively simulated). Active vessels with Pe even above 22 km will crash due to atmospheric drag.

Adding a probe core to a vessel has no effect on it being kept or destroyed. This is a persistent myth on the forums. However, a probe core will be classified as a probe and not debris, and debris is not shown on the map view by default. You ahve to mouse up to the top of the mapview and activate debris icons.

ALL THAT being said, if you want to use something as a refueling station, you're going to need a docking port and learn how to perform orbital rendezvous and docking maneuvers. You would also do very well to add a probe, some SAS, batteries and solar panels. This will allow you to keep the tank steady while it is being docked with. You really don't want to try docking to "dumb" target. It's a nightmare.

Fuel stations aren't neccessary for long range journeys, but they can help.

KAS is also a good mod for this. Just pull up beside the fuel tank, attach a fuel line and bobs yer uncle.

This is tricky and cause some severe oscillations in both craft due the fuel line being physics-less. It caused a real problem in one of Scott Manley's Insterstellar videos.

[problemecium]

Adding a probe core to a vessel has no effect on it being kept or destroyed. This is a persistent myth on the forums.

Not entirely. If you have unlimited debris in the game settings, adding a probe core will have no effect on objects in stable orbits or landed outside KSC. However with a cap on persistent debris (as mentioned above) objects lacking a probe core will be deleted if the number of persistent vessels is too high, and objects without a probe core that are left on the runway or launch pad tend to get deleted automatically (which has been a pain for me a few times in the past).

[Knacky]

Here's my huge fuel space station. 1467 parts and 1689 tons for the moment. I built it in 4 times : the in-line core with many RCS tanks, then the fuel tanks, then habitable modules, and finally more fuel tanks. On the picture you can see my Kethane Tanker on the right. It can land vertically on Mun, drill the ground to fill its tanks with Kethane, and take off to dock on the station again. This is pretty long to fill the whole station with fuel (almost 20 station-Mun-station trips).

On the left, you can see my huge interplanetary vessel, that holds 4 exploration vehicles (2 for Eve : a flying buggy with caterpillar tracks, and a glider - 2 for Gilly : a landable laboratory that can deploy a tiny flying vehicle).

It lags so much that it takes hours to fill all my vessel's tanks lol. At the moment, it's almost completely filled up. Time for interplanetary trip is approaching !

[Spatzimaus]

It lags so much that it takes hours to fill all my vessel's tanks

That's why I suggested, here and elsewhere, to make your refinery vessel act as a station by itself. I used to do something similar to you, with a 2-part design using a small lander with a big orbiting tanker, but I stopped doing that when they changed how SAS worked since it now meant you could do an all-in-one lander that still had enough steering ability. As long as the moon you're landing on has low enough gravity, you can do this VERY efficiently, too. Here's my tanker landed on Pol:

That's the thing with the physics. As long as you can find engines with the right combination of thrust and efficiency, there's no downside to going bigger. Instead of 20 trips with a small fuel vessel, you just do one trip with a vessel 20 times the size; it uses the same amount of rocket fuel for the descent and ascent, you're not wasting fuel matching orbits and docking, and it just takes a lot less of your time.

So, you just fill it up once, then return to orbit to fuel any passing vessels, like so:

(That's my favorite spaceplane docked at the end of one of the arms after a trip to Minmus.)

[LethalDose]

Not entirely. If you have unlimited debris in the game settings, adding a probe core will have no effect on objects in stable orbits or landed outside KSC. However with a cap on persistent debris (as mentioned above) objects lacking a probe core will be deleted if the number of persistent vessels is too high, and objects without a probe core that are left on the runway or launch pad tend to get deleted automatically (which has been a pain for me a few times in the past).

/sigh. Alright, fine. I was primarily talking about debris and vessels below 22 km being removed, but yes, If you push the amount of debris over the set limit (the default amount of debris allowed is 250), it will be removed as described. The point, though, is debris doesn't just disappear; there are commonly met criteria that triggers its removal.

Given the tone of the OP (refering to himself as naive, etc.), I really doubt that the tank he was looking for was removed because the debris limit was met on later launches.

[Thomas988]

Backing up what electronicfox said, you need some sort of control part on something you eject from your spacecraft. Otherwise, the game will recognize the tank as debris, and can possibly be deleted. Of course, if you're going to have a control part on your tank, you'll need a way to get power to it and yadda yadda yadda.

[magnemoe]

There's a catch 22 with that. The fuel line tends to be considered FAR more rigid than (in my opinion) it should be. If you have ships that have some minor stability issues they are exaggerated considerably and can cause a rather impressive Kessler Syndrome effect.

Yes, however you would just connect and transfer then disconnect.

The important part is to be less than 50 meters from the winch to target and 0.1 m/s relative speed.

[Madrias]

It's a good question, actually. Probe core, fuel tank, and docking ports make for good refueling cans out in space. I'm fairly sure most KSP players end up with at least one "gas station" in orbit due to the need of refueling SSTO's, long-range interplanetary ships, and a convenient place to dump rescued Kerbals.

[psyper]

not sure if this was suggested yet - but go back in the map mode - move your mouse up to the top center of the screen and a menu should drop down - select debris (far left icon) and this will show all the debris in the game - you should now be able to see your tanker and target it. but as suggested I would personally put a probe core, batteries and solar panels on it to or.....

... go big..

Edited November 13, 2014 by psyper

[Wanderfound]

Maybe I'm naive. I assumed that I could build a ship, launch it into orbit around Kerbin, leaving a huge tank of fuel circling the globe and then build another ship and launch that so that it rendevoused with the fuel tank in orbit and transfer the fuel from the one tank to the other or dock with the full fuel tank. When I built the second ship and launched I found that my orbiting fuel tank was gone or at least not showing on the map.

What is the correct way to do this? I want to build a refueling station in orbit and maybe another one in orbit around the Mun and then visit those stations with other rockets in the future. And if I can do this do I have to dock the empty tank with the fuel tank in order to transfer fuel or is it enough to pull along side?

Are fuel stations even necessary for long range journeys?

Another question involves tall rockets tilting way off vertical and falling apart. Do I need something besides ASAS to keep my tall rockets vertical?

Stock aero or FAR/NEAR?

Orbital refuelling isn't necessary for interplanetary travel, but it is very helpful. And the station does not need to be gigantic; a couple of Rockomax 74's is plenty.

You wll need to figure out orbital rendezvous and docking, but there are a large supply of forum threads and Youtube tutorials on the subject.

[FlamedSteak]

Refuelling stations can end up being more of a hassle than they're worth. With the big new engines that came in with the asteroid redirect pack it's a lot easier launching everything you need from the pad. Or if it's a really huge load; building your vessel in orbit. Managing a refuelling station turns into a chore pretty fast.

That being said, getting rendezvous down is one of the most helpful things you can learn in ksp. Being able to seperate your craft into an orbiter and lander opens up a lot of design options. Plus it's a lot of fun when you get good at it, nothing quite like a single approach and connecting the docking ports with a kiss.

[Spatzimaus]

Refuelling stations can end up being more of a hassle than they're worth.

Depends on what you're doing and how you're doing it. The best use of a fuel station, in stock, is a semi-disposable setup; loft a cluster of big tanks into low Kerbin orbit, and all the spaceplanes going up have a place they can top their fuel off before heading outbound to somewhere more interesting (like Laythe). Because of the size difference, you might get a dozen or more refuels off of each tank, and when the tank is nearly empty, just de-orbit it with a small engine. If you really don't want to waste money, just put some parachutes on it and recover the hardware. Refueling that depot from the ground is kinda pointless, since whatever carries the fuel up will cost just as much. (Unless the fuel depot is a station with other uses, of course.)

Also, fuel depots make a BIG difference for trips around the Jool system. Without them, you have to launch huge vehicles from Kerbin just to get any payload back from somewhere like Tylo. But send a big depot to Jool and you can now use a small vehicle to zip around Jool's moons; it's a lot more fun. Of course, sending that big fuel supply from Kerbin is a pain in itself, and you'll eventually run out...

But that's in stock. Once you add Kethane or Karbonite, things REALLY change since now your depots can refuel themselves from local resources. With something like the depot I showed above, you can get dozens of spaceplane refuels off each load of fuel, and refueling isn't much of a chore. I generally take one of those tankers, fly it down to Laythe orbit, and have it service any passing vessels there; once it gets low on fuel, it goes back up to Pol or Bop and refills. VERY useful.

[Wanderfound]

Depends on what you're doing and how you're doing it. The best use of a fuel station, in stock, is a semi-disposable setup; loft a cluster of big tanks into low Kerbin orbit, and all the spaceplanes going up have a place they can top their fuel off before heading outbound to somewhere more interesting (like Laythe). Because of the size difference, you might get a dozen or more refuels off of each tank, and when the tank is nearly empty, just de-orbit it with a small engine. If you really don't want to waste money, just put some parachutes on it and recover the hardware. Refueling that depot from the ground is kinda pointless, since whatever carries the fuel up will cost just as much. (Unless the fuel depot is a station with other uses, of course.)

Not necessarily; a good spaceplane tanker can deliver fuel to orbit for less than √1 per unit. I'll use one rocket launch to create the station, but resupply with spaceplanes from then on.

http://forum.kerbalspaceprogram.com/threads/90337-Economic-Fuel-to-Oribit/page5?p=1361984#post1361984

[Alshain]

Agree with Wanderfound on this one. My plane can deliver it's load of fuel to 300km using only the outer tanks to get there (Disclaimer: FAR), not counting the rear adpaters which is all you need to deorbit and land. I could probably do better than that if I tried hard enough.

[Spatzimaus]

Not necessarily; a good spaceplane tanker can deliver fuel to orbit for less than √1 per unit. I'll use one rocket launch to create the station, but resupply with spaceplanes from then on.

This doesn't contradict what I said. If you've got a good heavy spaceplane that can loft a decent amount of fuel, then you'd be better off simply using THAT as your fuel depot instead of a rocket-lifted station. Put a few docking ports on the plane and let smaller vessels link up with it as necessary; when it's nearly empty, return it to the surface. Or, build your plane such that it detaches a cargo of fuel tanks once it reaches orbit and returns immediately. Either way, there's just no reason to move that fuel to a station unless your planes' capacity is much smaller than that of the station (and with the way things scale in KSP, you CAN make the planes huge).

It's all about perspective. You're looking at it as the station as a baseline and the plane refueling as an efficiency improvement, when you could be looking at it as the spaceplane as the baseline and the station as an avoidable inefficiency. Now, I personally don't mind a bit of inefficiency if it looks cool, so I launch my depots with reusable rockets, but if I really cared about money I'd do it with planes.

[Slam_Jones]

Despite playing mostly in career mode, I tend to do my projects rather... un-efficiently.

Sitting in LKO with bay open.

This is what I use to refuel some of my ships: The Space Dock. Tends to bring me to pretty damn low FPS, but it's awfully satisfying docking a ship inside another ship.

Sent it up with about 1/12 of the fuel it can carry, and now building an SSTO that can bring Orange tanks up to re-fuel it.

In LKO with a Hawkeye Cruiser docked.

This is just one idea for what you can do. Like I said, not efficient at all really, but definitely fun.