Best engine and fuel tank for interplanetary transport.

[Cordeos]

I have finally started establishing a presence on and around the Mun and I have been trying to design a ship to move Kerbals between various orbital assets. So far my attempts have run out of fuel very quickly. What is a good engine and fuel tank combo for transport between space stations?

[stupid_chris]

This is a bit confusing, your title says "interplanetary transport" but your text says between stations and various orbital assets That's very different, so I'll do both:

First off actually, the fuel tank will only depend on how far you want to go. There's not really any good "combo", you just take the one that fits your delta V needs

Then, for interplanetary travel: you're definitely going to want to stick to the LV-N. It has a really low thrust and weights a lot, but it's efficiency overpower the other effects and really, doing interplanetary travel with another engine is often not worth it at all.

For orbital transportation, you have a larger choice: depending on the size of your ship, you're going to want to go somewhere between the Poodle, the LV-909 and the Aerospike. Personally I'm getting a lot of love from the Poodle. A lot of people hate it because compared to a cluster of LV-909 it'S not worth it, but it just looks really good on a ship and reduces the part count. But it just depends the size of what you move. When staying in the Kerbin SOI, LV-Ns are rarely really worth it because they're slow and heavy.

Just remember to take what fits your total mass the most and don't be afraid to use the LV-N if you're going away from Kerbin!

Good luck

[Alguien]

If you can get a NERVA (the atomic engine) with one of the big rockomax tanks (32 should be more than enoug, 64 is overkill) into orbit, it should be able to get you into any part of the system

[Margaul]

Your best bet is the nuclear engine with the big tanks (Rockomax) attached. They have a high Specific Impulse which is the rocketry version of fuel efficiency. (I believe the ISP in a vacuum is like 800). The downside of them is that they aren't very powerful. This isn't a problem in space, but it can test your patience. You may have to make multiple burns to transfer orbits.

Edit: Stupid_chris nailed it right on the head. The nuclear engine is the way to go for interplanetary travel, the poodle is your friend for orbital transportation. That's exactly what I do with my "Skycrosser IA" which was become the workhorse of my fleet. I can make it just about anywhere and back with this little ship. It has the LV-N system for long range trips, with the poodle for when I need a bit more power for faster maneuvers.

Edited June 19, 2013 by Margaul

[Sirrobert]

The Atomic rocket is by far the most efficient in space. If you want to save fuel, use this.

It does have pritty low thrust though, so you'll need clusters if you want to avoid having to burn for a very long time trying to get to outer planets

[capi3101]

I suppose it depends on how far apart your assets are located from one another. In theory, you could do it with RCS thrusters only, but that takes a lot of patience (though not as much as an ion thruster - which I have used before). Probably your best bet for this purpose is (as has been said already) the Poodle, LV-909 or Aerospike; depends entirely on the mass of what you want to move around. I've also had some luck with the Skipper in this regard, though that's really more than what you need (unless you're going to be making extreme changes in the inclination of your orbit). An X200-16 is probably a good place to start; add RCS (use the big tank) as a backup and for good measure use a command pod with a fair amount of torque (both of the lander cans work very well).

Interplanetary (like between Kerbin and...say......Duna or Eve), you definitely want a cluster of LV-Ns. Five LV-Ns and ten X200-32s will get you anywhere you want to go in the system easily (though don't expect great performance or handling if you go anywhere with that much fuel...).

[Cordeos]

Your best bet is the nuclear engine with the big tanks (Rockomax) attached. They have a high Specific Impulse which is the rocketry version of fuel efficiency. (I believe the ISP in a vacuum is like 800). The downside of them is that they aren't very powerful. This isn't a problem in space, but it can test your patience. You may have to make multiple burns to transfer orbits.

Edit: Stupid_chris nailed it right on the head. The nuclear engine is the way to go for interplanetary travel, the poodle is your friend for orbital transportation. That's exactly what I do with my "Skycrosser IA" which was become the workhorse of my fleet. I can make it just about anywhere and back with this little ship. It has the LV-N system for long range trips, with the poodle for when I need a bit more power for faster maneuvers.

I just used a version of this ship (added more RCS fuel) to move a Kerbal from my Mun station to my Kerbal one. Thanks for the design!