Building my first space station, a few questions.

[Vozlov]

Hi Kerbonoughts.

So I'm currently designing and building my first space station, but have run into some design bottlenecks and need a way around them. I've got my heavy lifter sorted, and have experimented putting sections into orbit. I reckon I'll be able to pull this together, so I'm working on 'reusable' shuttles in order to ferry both passengers and fuel, using the station as a fuelling platform for interplanetary rockets I intend to build later.

Is there any way to have three of the same type of fuel canisters stacked, but have it so only one of them is actually being used to fuel the booster? I want to use two of them for orbital refuelling so they need to stay completely unused, so I use the third to align the orbit and dock, and use anything left over to land back at base.

I was experimenting with jet fuselages, but these obviously won't be any good for orbital alignment, wouldn't be any good for fuelling an interplanetary space ship, and they completely screw up the balance on account of them being shaped so differently!

Also, Is there any preferred height for space station orbits? The ISS is at a 330km orbit, but due to KSP scaling this just seems far too far. What would be considered a low earth orbit in KSP?

Cheers!

Edited February 13, 2014 by Vozlov

[Raven.]

Is there any way to have three of the same type of fuel canisters stacked, but have it so only one of them is actually being used to fuel the booster? I want to use two of them for orbital refuelling so they need to stay completely unused, so I use the third to align the orbit and dock, and use anything left over to land back at base.

Yup, right click on the fuel tank and click on the green arrow button. It will change to the same icon except with a red slash through it. That will stop the fuel flow from that tank. Also check out this if you don't mind mods, this mod has fuel control parts.

Also, Is there any preferred height for space station orbits? The ISS is at a 330km orbit, but due to KSP scaling this just seems far too far. What would be considered a low earth orbit in KSP?

Depends. I think some people will throw their stations in the 300-500 km range depending on the purpose of the station. I typically throw mine up at 120 km.

[Vozlov]

Ahha! Cheers Raven, much obliged. My space station can now continue development! A new question then, how do I change this thread to answered?

[capi3101]

Edit your initial post. You might have to go under advanced settings; there will be an option to change the initial status there.

[Claw]

Edit your original post and click "go advanced." You can change it in there.

Ninja'd by Capi!

[Jouni]

Also, Is there any preferred height for space station orbits? The ISS is at a 330km orbit, but due to KSP scaling this just seems far too far. What would be considered a low earth orbit in KSP?

There are several factors to consider:

1) You need less fuel to reach lower orbits. This is especially important for spaceplanes using RAPIERs.

2) Interplanetary launches from low orbits are more efficient but less accurate.

3) After a badly timed launch, you need to wait longer for the next transfer window, if the station is at a low orbit.

4) Apparently 160 km is the upper limit of drawing some details on Kerbin's surface. If that's true, large stations above 160 km may experience less lag.

Previously I considered 120 km orbit a good trade-off, but because of 4), I would now put my station a bit above 160 km.

[Taki117]

There are several factors to consider:

...

4) Apparently 160 km is the upper limit of drawing some details on Kerbin's surface. If that's true, large stations above 160 km may experience less lag.

I generally put my stations at 200km for this reason, and I like nice round numbers.

[Kryxal]

Incidentally, if you use some of the fuel from the wrong tanks, you can just manually shift fuel back once you dock the tanks but before you detach the "booster" tank.

[Seret]

Also, Is there any preferred height for space station orbits?

Depends what you intend to use it for. If it's a fuel depot for orbital ops then you'll want to put it at the same sort of height you'll be operating at. I tend to keep mine quite low (75km-ish) but there's something to be said for putting it above 120km so you can warp faster if you're executing your approach from a lower orbit.

If your station is manned then your escape system's capabilities might be a constraint on the altitude you choose. I tend not to have personnel on board fuel depots myself, it's just an unnecessary risk IMO.

Edited February 13, 2014 by Seret

[Justin Kerbice]

Interesting informations, could be gathered into a "space station Q&A".

[Rodyle]

There are several factors to consider:

1) You need less fuel to reach lower orbits. This is especially important for spaceplanes using RAPIERs.

Eh... I don't know. The fuel needed is not actually all that much more, from my experience.

2) Interplanetary launches from low orbits are more efficient but less accurate.

True, but I haven't seen the maths on the savings. Anyone has some equations for this?

Previously I considered 120 km orbit a good trade-off, but because of 4), I would now put my station a bit above 160 km.

I usually do them around, mainly for the extra fast time warp.

[3Dave]

Also depends on if you plan to use mechjeb to automate some of the mundane tasks for you like orbital rendezvous. sure its fun the first few times, but once you know what your doing, it gets to be a chore real fast. plus no real rockets are flown stick and rudder, ever.

For this reason i put my stations at around the 300km mark to cut down on extra transfer maneuvers. the extra delta v needed to reach the higher orbit is negligible unless your heavy lift upper stage/tug is extremely inefficient. you also get a very nice view at higher altitudes.

[Vozlov]

Very interesting information. Cheers people.

I'll be putting the station at around 150km I think, my reusable shuttle will be able to make that easily, as its actual non re-usable launch system has quite a large range. In theory I could possibly get the thing to the 300km range, but the place is manned as its also going to be used for 'astronaut acclimatization' and perhaps be the area I actually build the rocket itself should that turn into something much larger than I have envisioned.

This game kicks ass.

[Jouni]

Eh... I don't know. The fuel needed is not actually all that much more, from my experience.

The difference is not too big, but it can be significant for SSTOs using RAPIERs or lifters carrying close to their maximum capacity.

[DerekL1963]

Depends what you intend to use it for. If it's a fuel depot for orbital ops then you'll want to put it at the same sort of height you'll be operating at. I tend to keep mine quite low (75km-ish) but there's something to be said for putting it above 120km so you can warp faster if you're executing your approach from a lower orbit.

Where your fueling stations go depends heavily on where they fit into your operational scheme... In one setup I used tankers to move fuel about (the tugs being refueled were too large to reasonably dock) and in the end it made more sense to put my huge tank farm down low (around 100km to stay clear of my 75km parking orbit and to use less fuel getting the fuel into orbit) and use tankers to refuel my tugs in a 200km orbit.

[Pestilence]

I personally put my refuelling station at 610k so I can utilize the full 100,000X warp, but I also don't use SSTOs which would make that impossible. Getting to 610k, the heavy lifter is obviously gone, and if my payload is heavy enough, the first stage of my asparagus'd high-efficiency deep space tug is often spent, but so what? I don't eject that stage, I just pull the dead weight to the station and there refuel them all. Then I have a LOT of delta-v available from pretty high up out of Kerbin's well already, plus the fastest warp available.

[flyboy67109]

I stared here: http://wiki.kerbalspaceprogram.com/wiki/Tutorial:Salyut_programme

I found it very educational. The author built it with an earlier version of KSP, I think, because you have to modify some of the modules to get them to work right. But, that makes for some fun explosions and I learned what could and could not work. I started by making the Proton K and Soyuz rockets first and then made the Progress rocket. Once I felt comfortable with my design modifications, I moved to launching a Salyut 1 station with the Proton K. Put kerbals in it with the Soyuz and, finally sent a supply ship up on the Progress. Worked my way through the entire page. Lot of work but fun especially the deorbiting of the stations. Hope that helps. Good luck.

[Kerba Fett]

One thing I haven't seen mentioned here is that when you rendezvous your ship is normally in a lower orbit than your station.

I use an elliptical orbit with my AP at 200km. (same as the station orbit) the PE is usually about 70 to 80km to keep me out of the atmosphere. Because my orbital period is shorter than the station, I eventually catch up with it without using any dV till the last orbit when I raise my PE just enough for a close rendezvous.

If your station orbit is too low you don't get enough difference in orbital period and it takes a lot more orbits.

If you use a higher orbit for your ship so the station catches up with you then you need to burn fuel to raise your orbit then later burn more fuel to lower it.

If you want to get the maximum fuel load to the station you're pretty much forced to put the tanker into the lower orbit.

[Seret]

Since this is your first station Vozlov it might be worth mentioning a couple of other points besides altitude. If this is a station that you'll be docking with lots then you might want to have a think about optimising the design to make docking easier.

• Docking is a lot easier if you can rotate the station so that the docking port faces the approaching ship. Install enough reaction wheels to rotate the station easily.
  
• Likewise, don't make it long and spindly, or put heavy things on the end of long trusses. Keep the heavy modules towards the center, or well braced. Building around a central core, instead of in a linear design will help. Use the big docking ports to connect sections. A wobbly station is a bad station.
  
• Plenty of lighting will help you dock on the dark side. Don't forget enough batteries!
  
• Keep your docking ports clear of stuff like solar arrays, but make sure they're not too far from the centre of mass. Big heavy ships or fuel tanks on the end of long trusses will be wobbletastic, which makes docking other stuff harder.
  

[Rabada]

I sometimes like to put my stations above 600 km because at that altitude you can use the fastest time warp setting.

Edit: whoops, I somehow missed Pestilence giving the same advice

Edited February 14, 2014 by Rabada

[m4rt14n]

200 km is preferable, because it makes randevous manuevers easier. Since you dont want to be below 75km

[Jouni]

• Docking is a lot easier if you can rotate the station so that the docking port faces the approaching ship. Install enough reaction wheels to rotate the station easily.
  
• Keep your docking ports clear of stuff like solar arrays, but make sure they're not too far from the centre of mass. Big heavy ships or fuel tanks on the end of long trusses will be wobbletastic, which makes docking other stuff harder.
  

Ultimately it will be easier to learn to dock with stationary targets that don't turn to face the approaching ship. Space stations have a tendency to grow organically when they are in active use. Eventually even the best designed and most maneuverable station will grow into an ugly wobbling mess, where the last free docking ports are surrounded by all kinds of obstacles.

This discussion inspired me to move my LKO station from a 120 km orbit to a 160 km orbit to reduce lag. Then I had one look at the station, and decided not even to try.

[Seret]

Ultimately it will be easier to learn to dock with stationary targets that don't turn to face the approaching ship. Space stations have a tendency to grow organically when they are in active use. Eventually even the best designed and most maneuverable station will grow into an ugly wobbling mess, where the last free docking ports are surrounded by all kinds of obstacles.

Maybe, but I'd still design it to rotate easily in the first place, so you have an easy life up until the point things go horribly wrong.

This discussion inspired me to move my LKO station from a 120 km orbit to a 160 km orbit to reduce lag. Then I had one look at the station, and decided not even to try.

Hey, you managed to get the whole thing from the launch pad at KSC up to 120km! A little bit of an orbital shimmy should be no trouble, just break it down into two or three pieces and go gently.