Non Atmospheric Lander/Lifters - Help Needed

[Neros]

I seem to be having some problems with designing and developing a lifter/lander for the non atmospheric planetoids. Getting it into orbit is easy, its getting it off other planetoids with a payload that is the hard part. Any suggestions would be welcomed. So before I go into any full details I am going to list the mods that I am using and KSP Versions.

KSP 0.21

B9 Aerospace Pack R3.3 : http://kerbalspaceprogram.com/0-20-2-b9-aerospace-pack-r3-1/

H.O.M.E. 1.0.5 : http://kerbalspaceprogram.com/0-18-1-h-o-m-e-start-kit/

“Jool Vâ€ÂHeavy launcher 3m v1.2 : http://kerbalspaceprogram.com/0-18-1-heavy-launcher-3m-jool-v/

Kerbal Attachment System v0.3.1 : http://kerbalspaceprogram.com/0-18-2-kas-kerbal-attachment-system-v0-1/

MechJeb 2.0.9 : http://kerbalspaceprogram.com/21mechjeb209/

So here is the grand idea behind it all. My objective is to create a base on any planetoids using the H.O.M.E. Modules. Stationed in orbit around said planetoids with be a fueling station. The H.O.M.E. Modules are easy enough to land them and get them set up. One of the H.O.M.E. Modules comes with a Miner system that you can use to mine fuel or mono from said planet (Mun for instance). I will be using the Kerbal Attachment System to transfer fuel from the HOME Miner to the lander/lifter. The hard part is getting the lander/lifter up and into orbit around said planet to dock at the fueling station with its payload so I can transfer the fuel from the lander/lifter to the fueling station. Another thing to note is that the reason for the fuel station and lifter/lander is for the mother ship that will need to refuel for its trip back to Kerbal.

I was wondering if you guys can help me out with a few designs for the lander/lifter and the fuel payload. I would like a single stage that can lift about 740 fuel and oxidizer into orbit without the lifter using that payload for fuel. Its a changeling undertaking that I just cant find any information for. Any pictures that you have of your designs are welcome.

PS: I will be posting pictures of a few design that I have in the next few days.

Edited August 30, 2013 by Neros

[Specialist290]

Threw this design together in the VAB:

All stock parts, with the obvious exception of the KER chip I used for the data readout. The craft is optimized for use on the Mun, with enough fuel to make a round trip from a low orbit and back with fuel to spare and without using the fuel in the middle (assuming good piloting); performance should be slightly better on Ike and Dres, slightly worse on Eeloo, and absolute overkill for the smaller moons like Minmus, Gilly, Bop, and Pol. (You could also probably use it on Vall, too, but I'm less sure on the landing numbers, though it's going to be 8 tons lighter for the return trip to the surface with that middle tank empty. Don't even think about Tylo; you could probably make it down and back with all the fuel lines hooked up to draw from the center tank, but you wouldn't have very much fuel left for the fuel depot.) The middle fuel tank is a Rockomax X200-16 fuel tank, capable of carrying 720 liters of fuel and 880 liters of oxidizer.

Looking back, I should probably have given it an RTG or two instead of the solar panels, so that it can operate continuously in the dark, but that's the result of me trying to put together a lander like this in ten minutes while being way past my usual bedtime.

Edited August 24, 2013 by Specialist290

[maltesh]

This would be the a previous version of a surface-to-orbit tanker I was using over the Mun.

In the configuration as shown, it uses about a sixth of the fuel in the central tank to get from the surface to a Munar orbit; Get rid of the fuel lines and the side-tanks provide enough fuel to pull that off easily, with enough to stick a landing again with the center-tank empty.

I wound up scuttling the design, it doesn't really need anywhere near the amount of monopropellant it carries, the KAS ports are too high off the ground for easy Kerbal access, and it doesn't have its own winches.

Edited August 24, 2013 by maltesh

[Johnno]

Its a changeling undertaking that I just cant find any information for. Any pictures that you have of your designs are welcome.

All the information you really need is to have a TWR above 1 and enough delta-v to reach orbit. There are delta-v maps around on the forum/wiki and MechJeb vill give you delta-v information for your craft. For non-atmospheric planets/moons I'd recommend LV-N engines.

There's also plenty of pictures/ideas for landers/lifters in spacecraft exchange forum section.

[dave4002000]

I seem to reference this craft more than i thought i would. This is my kethane dropship using spherical tanks. 24000 units of kethane into orbit but you could easily replace those tanks with LFO ones if that's what you're doing. Those are 4 LV-N's clipped into the radial tanks, but 909's would probably work just as well(maybe better, even).

[Captain Sierra]

Okay, use the LV-909s. They have the best ISP AND TWR in vacuum, which cannot be said for the low TWR of nukes. for a lifting lander, 4 of them should be sufficient. Test it on the Mun. If it works there, it can work on any non-atmospheric body other than Tylo.

[TheDarkStar]

Okay, use the LV-909s. They have the best ISP AND TWR in vacuum, which cannot be said for the low TWR of nukes. for a lifting lander, 4 of them should be sufficient. Test it on the Mun. If it works there, it can work on any non-atmospheric body other than Tylo.

Nukes don't have an abusrdly low TWR, but they weigh enough that they are less efficient on smaller ships. 4 LV-909s seem overkill though, you should be doing it with one or two (unless on Tylo).

[esinohio]

People above made awesome suggestions. Since you are using mods I'll add that maybe you want to nab that Kerbal Engineer that is pictured in one of the posts above. It will make solving your deltav issue MUCH easier since can easily change between different reference bodies within the mod. It defaults to showing you all the information assuming you are on Kerbin, pressing the button corresponding to the planet you are wanting to escape from you will see how your ship will behave there. Combined with the DeltaV map mentioned in another post you can do all your planning safely in the VAB with no issues. Good luck!

[Specialist290]

4 LV-909s seem overkill though, you should be doing it with one or two (unless on Tylo).

I'll admit 4 LV-909s is a bit overkill for Mun liftoffs with that thing, but I chose that configuration for my own design because I wanted the craft to be symmetrical and have the 90-degree facings free for RCS ports (I know it doesn't really matter whether or not they're blocked by something, but I think it looks better when they aren't) and to keep the fuel tanks on the engines from rising above the central fuel tank while still keeping it accessible to ground level (since the OP said he was using KAS for refueling).

[Neros]

Guys, I wanted to say thanks for all the hard work, pictures of your designs, and helpful information. Some great concepts in here. Im going to leave this tread open for the next few days if you guys have any more information to share. Also I wanted to post some of my designs that I have made for this subject. I never made it to the Mun to test it (mainly because I got a little to wasted that night to try lol) but after looking at a few of your designs, this thing might be a bit of over kill.

This is my most common workhorse that I use to get things in orbit, great for lifter more then 50 tons.

[dave4002000]

In case you don't know; Unless you are using the FAR plugin, all those nosecones do nothing but add extra weight and lower your total delta-v. Of course, if you just want it to look more "rockety" then, by all means, use them

[numerobis]

A TWR of 1.45 on Kerbin is a TWR of about 10 on Mun. I recommend you dial back on the thrust!

[Specialist290]

I'm curious. What's your reasoning behind the reversed engines on top of the lander?

[Geschosskopf]

I was wondering if you guys can help me out with a few designs for the lander/lifter and the fuel payload. I would like a single stage that can lift about 740 fuel and oxidizer into orbit without the lifter using that payload for fuel. Its a changeling undertaking that I just cant find any information for. Any pictures that you have of your designs are welcome.

You need at least 1 mod to answer this question: Kerbal Engineer. Then in the VAB you can set it for whatever world you're interested in and see what it tells you.

Then you need to know the mass of the ship when loaded and ready to lift off from whichever planet. So you build your cargo container (cargo bay, empty Kethane tank, etc.) and hang whatever rockets on it you think will do the job. Then you add some extra parts to equal the mass of the loaded cargo container minus its empty mass (which you already have). NOTE: These extra parts must NOT contain fuel or they'll screw up the dV calculatins. Now, you can see if Kerbal Engineer says you've got enough TWR to lift and enough dV to reach orbit.

Myself, I lift a lot of Kethane and its tanks start empty, so I build a rocket around the empty tank I want to use. I also have the Orbital Construction mod, which I don't actually use for its intended purpose. However, this mod has some parts that are just dead weight of many tons, and they come in various sizes. I find them ideal for stacking on top of my would-be Kethane lifter to see if it can do its job because otherwise I'd have to use literally hundreds of batteries or some other inert stock part.

[Neros]

I'm curious. What's your reasoning behind the reversed engines on top of the lander?

The engines are for slowing the ship down on approach when docking. And Geschosskopf your right about the mun and TWR, I didn't think of it until I tired it out on the mun last night. Coming back into work on progress. As of right now, I'm thinking of taking off the HOME mod and using the Kathane mod instead. Either or, It will make design much easier.

As a side note, I have been trying not to use MechJeb. It bogs my computer down. I seem to enjoy getting my ship into orbit and docking without it much more... Its harder but well worth it. Been spending a ton of time on that lol...