Spacestation location?

[maceemiller]

Hi all. Ok, so im starting to build a spacestation with a view to start mining and going to other planets. My question, albeit a silly sounding one is where to put my station? Is it better for me to put it in a high Kerbin orbit, mine from the Mun or Minmus and transfer fuel to the station, or put a station around the Mun for example and go to other worlds from there?

I only play sandbox so efficiency isnt really an issue. Been thinking about this for a day or two but would love some expert opinions. Thankyou in advance

Edited July 20, 2015 by maceemiller

[Tex_NL]

Personally I'd go for a three pronged approach:

1. A ground based mining opperation near the equator on Minmus.
   (The low gravity makes it easy to land.)
   
2. A cargo shuttle to ship fuel.
   (It only takes a small amount of fuel to return to Kerbin.)
   
3. Fuel storage station in low Kerbin orbit.
   (In low Kerbin orbit you can maximize the benefits from the Oberth effect when going interplanetary.)
   

[Foxster]

To be honest, a mining base on a moon or another planet is still more an exercise in fun than practicality. There is nowhere you can't explore in the system with a single or multiple launches from Kerbin that would be improved by refuelling en-route.

If you want to do it though then using Mimus is probably best. It's cheap to get to, cheap to capture an orbit and cheap to get refuelling tugs up and down from the surface.

[Glaran K'erman]

I'm just basically echoing Tex and Fox, but yes if you were to set something up Minimus would be best. And in all honesty you could set up the fuel station in either LKO or Minimus orbit, either way you're going to have to send the refueler from Minimus to LKO and back, or the vessel you want refueled to Minimus and back, but like Fox said I would still start any trip from LKO.

[jwenting]

way I've done it in the past (running kethane) was to mine on the Mun or Minmus and have a refinery in orbit to turn that ore into fuel. It's not the best for fuel efficiency if that's what you're looking for as you have to of course refuel the ships delivering ore to the refinery, but it allows refueling ships that don't have a landing capability.

[Alshain]

My favorite place is at about 300km around Kerbin. It's easy to get to and the view is perfect! I usually refuel my stations by launching from Kerbin. I see no need to go to the trouble of ISRU anywhere near Kerbin.

[Edax]

What I do is send a station to Minmus, land it, mine until the fuel and ore tanks are full, then just take off and return to Kerbin Orbit loaded with fuel and ore, ready to be used as a docking hub by SSTOs and other vessels that need fuel and crew transfers.

[Glurth]

Wanted to throw out an alternative to using Minimus. I'm working on setting this up now in my career game, so I have NOT tested it yet; think it will work?

Bring a large mine-able asteroid into Kerbin orbit. Park it in a highly elliptical orbit, such that the apoapsis is pointing directly at your Ejection angle, and very high (just short of escape from Kerbin). You can burn a ton of fuel to dock with your mining base on the asteroid and then refuel. Then with only a tiny burn at periapsis you will be launched into your interplanetary trajectory. It should cost no more that a dozen m/s in Delta V to get out of Kerbin's SOI. To figure out the best ejection angles (and asteroid/fuel-station parking orbits) for each planet, I used this link (http://ksp.olex.biz/). Keep in mind, this WILL limit your launch windows to certain planetary phase angles (which should occur approximately once per year). Warning: Wrangling large asteroids around can be quite challenging.

[maceemiller]

Well thankyou for all your replies....I think I like Alshains post so will park there.....and also try some other replies. Thankyou all again

[cantab]

I would put it in Mun orbit. Interplanetary ships can depart from there for about 500 m/s less than a departure from LKO, meaning they can be smaller. The Mun's orbit is quick enough that you won't miss transfer windows waiting for it to get into the right position, and when going to Eve or Duna you can depart directly from Munar orbit which makes life simpler. Mining operations on either the Mun or Minmus can reach the station for reasonably cheap delta-V costs.

The problem with low Kerbin orbit stations is that your interplanetary ships still need to make their ejection burns from there and thus can be no smaller than if you just launched them full. Any ships too big to easily launch full are likely to be so big they'd drain a fuel station dry and so it's better to launch specific fuelling missions for them.

The problem with Minmus is its long orbital period. You'll be waiting for it to move into the right position so you can drop your periapsis low over Kerbin, then burn there to go interplanetary. Getting the timing right is tricky. Unlike from the Mun, a direct interplanetary burn from Minmus orbit is always inefficient.

The problem with high Kerbin orbit stations is they're just a bit annoying to get to. In particular if you supply them from the Mun or Minmus you'll always have to worry about transfer angles and phasing orbits. And yet again you'll always have to drop your periapsis low over Kerbin for an efficient departure.

There *might* be a sweet spot for a Kerbin orbit station. High enough that interplanetary departures are cheaper than from LKO, low enough that simple direct departure burns are efficient. I've no idea where this is.

[FlyingPete]

I would go for a station in Mun orbit to do the actual fuel refining. Have mining landers go to the surface and drill for ore, then bring it back to the station for processing. That way you can make a large station with lots of solar arrays for power, and enough tanks that you don't run out of storage.

The simplest in terms of hardware would be to send your interplanetary ships directly to the Mun station and refuel there. You can either launch directly from the Mun station, or alternatively launch into an elliptical Kerbin orbit with a low periapsis. This way you can maximise the Oberth effect by making a small burn at low altitude. This does however slightly complicate things for planning the maneuver- the Mun has to be in the right position, and you have two SoI changes to consider (Mun>Kerbin, Kerbin>Kerbol).

Slightly simpler in practical terms might be to have a second fuel dump station in a high Kerbin orbit, and send the interplanetary ship there. You'd need a couple of fuel tankers to bring fuel from the Mun station down to the fuel dump. To go interplanetary from here, it would again be efficient to make a retrograde burn first, before making a second low-altitude burn into a Kerbin escape trajectory. With this approach you could also have a second mining operation on Minmus and bring fuel from there too.

[Hagen von Tronje]

Personally, since you're playing sandbox I'd set up a modular/expandable station with well placed docking ports in LKO, then build a modular "chunk of fuel tanks" that can be docked to said station and a tug/lifter that gets it there. Expand station with fuel reserves as desired. Since it's sandbox, there's no reason you can't make the tug only barely get there, dock it, break it off, then delete the debris from KSC, making the design much simpler than a reusable tug and failure much less troublesome since you simply revert launch if things go badly. As fuel gets used you can just dock and refuel then delete the entire tug and tanks. Basic probe cores provide full SAS in sandbox as well so they can be unmanned making the deletion that much simpler.

If you built things wisely you can then tack an engine module to the end of said station and push it as far as you like, using it as a gloriously gigantic "mid stage" to go to whichever planet you feel like. Build a mining lander and use it + shuttles to refuel the station at moons or planets. Or, just fill up a regular ol' midstage that's also capable of acting as a lifter to the station, allowing you to cut out the first stage entirely if you like compact or low part count rockets, though this seems like more trouble than it's worth.

Personally I think mining is best done in sandbox mode in places where you can't easily just lift up fuel at will from Kerbin, like on a moon of Jool or the surface of Eve. I also think that if you build direct ascent landers, mining facilities straight up "pay for themselves" in weight by letting you take only what fuel you need to make the landing with empty tanks that hold enough, when filled, to return to Kerbin (or wherever they're going actually, this applies also to landers from orbiting stations as well if they're large enough, like a construction platform). I made my direct ascent Munar landers lighter by replacing fuel tanks with mining to refill other tanks.