Space station and interplanetary ship building

[Tandy45]

I was wondering if some of you, would be able to give any tips on how to make a space station core and the design of an interplanetary explorer?, I've had a nosey and I haven't been able to find anything describing the method for either of these. I know about creating the necessary delta v to get to orbit, transfer and return however I'm hitting the problem of designing. I've used asparagus staging to reach the Mun and Minmus but I think trying to go further afield is daunting. Would it be better to build in stages and assemble in orbit, or build in one stage? if so what designs would be applicable and cost effective, I'm not looking at using other peoples craft more get a basic handle on things so I can at some stage design my own competently. Going back to the space station what would be an ideal core to begin with? Cheers.

[dzikakulka]

If you will not overengineer stuff, keeping it as light and compact as your objective allows (most people and especially I do suck at this) you can reach for as far as Duna reaaally easily. As soon as you have access to docking ports you should almost never land with your actual ship (meant for travel back to kerbin) - as long as it isn't Eve, compact lander will do a lot better with smaller engines, better control and using a fraction of fuel you would burn otherwise.

While space stations may be fun, in stock game they aren't that useful. You could do just as good with one or two-use simple rocket consisting of tanks, engines and docking port. Scatter few on orbits you're gona visit, refuel main stuff, crash/terminate now useless tanker. I can't really say if that's feasible or not considering cost, money in ksp is kinda easy to get.

An actual space station that would be useful (I think) would be one consisting of fuel tanks (I mean excess fuel to spare), lab+kerbals and ofc docking port. Put it on suitable, low orbit of some interesting body (Mun/Minmus ) and harvest science by landing on biome with small, science loaded lander and then ging back to dock with lab to reset science jrs and goos.

[Geschosskopf]

I was wondering if some of you, would be able to give any tips on how to make a space station core and the design of an interplanetary explorer?, I've had a nosey and I haven't been able to find anything describing the method for either of these. I know about creating the necessary delta v to get to orbit, transfer and return however I'm hitting the problem of designing. I've used asparagus staging to reach the Mun and Minmus but I think trying to go further afield is daunting. Would it be better to build in stages and assemble in orbit, or build in one stage? if so what designs would be applicable and cost effective, I'm not looking at using other peoples craft more get a basic handle on things so I can at some stage design my own competently. Going back to the space station what would be an ideal core to begin with? Cheers.

Well, the whole thing depends on what the mission is. First you have to decide what you want to accomplish and design 1 or more payloads to do that/those job(s). This determines everything else in terms of how to get these payloads off the ground, out to wherever you plan to send them, and bring them back (optional). Without knowing what your payloads will be, it's impossible either to design their transportation system or give you any specific advice.

In general, however, there are a few pointers I've found useful. First, if you're playing in career, payloads are usually relatively cheap compared to their required lift and transfer rockets. And the bigger the rocket parts you use, the more expensive the individual parts. So OT1H you want to minimize the number of launches because launches are more expensive than payloads. But OTOH, minimizing launches means launching bigger payloads, which need bigger, more expensive rockets. So there is a break-even point for cost between these 2 methods. I can't yet say exactly where it is but my experience so far indicates that if you can launch the payload with a fairly simple rocket (meaning a central stack with at most only a few SRBs and/or asparagus stacks), regardless of its diameter, this seems to be cheaper than herniating yourself with some colossal lifter or going nuts with small stages like you're trying to take off from Eve.

[Streetwind]

As far as space stations go, I found it's best to build a highly modular central core and insert that into your desired orbit. Just have a probe core, some batteries and some control (reaction wheels / RCS) there, possibly a communications antenna. And then docking ports. Lots and lots of docking ports. That way your core itself doesn't get too heavy, and can be launched relatively painlessly. Everything else can then follow piece by piece, docked to one of the many available docking ports on the core.

Here's an example I built in low Kerbin orbit a few months ago: https://dl.dropboxusercontent.com/u/44754370/screenshot27.png (built in Better Than Starting Manned, which is why it has no reaction wheels at all.)

This is a 2.5m core built by sticking the flat rockomax adapters to the rockomax multihub. They fit perfectly that way, turning the 1.25m hub into a 2.5m hub. Then I just stacked them vertically, with RCS tanks in between as spacers so the ports are not too close together. You can stack as many as you want. The 4 free sides got plastered with 2.5m docking ports. Some batteries and a probe core and an antenna on top. Also a 2.5m docking port on the bottom. And because I felt like it, I also rotated the middle hub by 45 degrees so the available room will be utilized better.

It was kinda large, but surprisingly lightweight, especially with the RCS tanks empty. You can basically stick some expendable radial boosters to the RCS tanks instead of trying to place it on top of something (though with struts that might also work). That was the first launch. The second launch was the small 5-way docking assembly at the bottom. Third and fourth launches were the two solar arms.

Launches 5, 6, 7 and 8 were the four fuel tanks. Yes, those are maximum size kerbodyne tanks, and they were launched full. Each tank had a small 0.625m control unit attached to the rear of it - junior docking port, RCS tank, battery, probe core, a set of RCS thrusters and a rockomax 48-7S. After being put into orbit, the little engine was able to use fuel from the tank itself, because docking ports don't block fuel crossfeed (but can still be used just like a decoupler can). Thus the tank performed the station rendezvous on its own (cost only one or two percent of its contents), docked, and then decoupled that little control section. Which used the remaining RCS that it had to deorbit itself.

Didn't continue building because I didn't really have a use for it then, but hey, maybe it serves as a useful example for you

Edited August 18, 2014 by Streetwind

[cantab]

For stations, if you're not using something like KAS or Quantum Struts, wait until you have Sr docking ports, you'll benefit from the stability. And watch your part count on the station. You can design a tug to put your modules in place, or else arrange their RCS etc so it can be decoupled after the module is attached, so that you don't have loads of redundant hardware left around.

For interplanetary ships, I would suggest a modular design with three parts, your orbiter, lander, and transfer stage, linked by docking ports. Whether you actually launch them separately or together is up to you. The lander can be left behind at the destination, though you might employ the trick of taking a probe core from it so the mission gets recorded as returning from the surface. The orbiter can land back on Kerbin. The key is the transfer stage - park that in Kerbin orbit, then you can refuel and reuse it for your next mission.

[Red Iron Crown]

Very generally speaking, launching one big ship (either station or interplanetary ship) is preferable to assembling in orbit from a structural standpoint. Properly strutting the ship makes it much more rigid and usable; using only docking ports to assemble needs to be managed carefully to keep the ship from becoming too wobbly.

Economically, it's best to assemble in orbit, launching your components in a reusable jet-assisted SSTO.

A good core for a space station is the Hubmax multipoint connector with a bunch of docking ports; this will allow you to add modules in six directions. Your first module should include an RCS system, electrical system, probe core and perhaps a reaction wheel.

[Pecan]

Chapters 7 and 8 of the tutorial in my signature cover space-stations, transfer vehicles designed never to land and dedicated landers that, er, are. Designing your own is a good plan but the ideas there should help you. The whole tutorial is available as a PDF download - link in the OP - and you can also download all the .craft files if you wish to start from what I built.

Like this:

Edited August 18, 2014 by Pecan