Can this land on the Mun and return?

[JenBurdoo]

As you can see, it's a stretched Kerbal X, with more fuel in the boosters, first and landing stages, plus lights, RCS and repositioned landing legs. I think it's got the required Delta-V. I understand Minmus can be easier to reach, so if this can make the Mun I may be able to use it for both.

I just flew it (with original-size boosters) on an Apollo 8 style mission to Mun orbit and back, but wasn't sure enough of its being able to land and return. I'm fairly new to the game, so even that took some trial and error. Thoughts?

[Giggleplex777]

It should be enough, but lander's TWR is kind of low, so be careful during launch.

BTW, pres f1 to take a screenshot and f2 to hide the UI.

[UmbralRaptor]

It'll work. I could point to design optimizations, but it looks like like it has enough ÃŽâ€V for a Mün landing/return already.

[JenBurdoo]

It should be enough, but lander's TWR is kind of low, so be careful during launch.

Hm, you're right. Doesn't that mean it can't take off, though? It has to be over 1.0? I suppose during TLI and landing I'll have burned some fuel though.

BTW, pres f1 to take a screenshot and f2 to hide the UI.

I used Alt-prtscrn, is that not preferable? Also, what's UI?

It'll work. I could point to design optimizations, but it looks like like it has enough ÃŽâ€V for a Mün landing/return already.

Feel free, I'm very much a newbie here. Thanks for the comments!

[Giggleplex777]

Hm, you're right. Doesn't that mean it can't take off, though? It has to be over 1.0? I suppose during TLI and landing I'll have burned some fuel though.

I used Alt-prtscrn, is that not preferable? Also, what's UI?

Feel free, I'm very much a newbie here. Thanks for the comments!

After you drop the big booster stage, the TWR of your lander will be lower than 1, which shouldn't be too much of a problem since you're already going pretty fast. Just make sure that it doesn't fall back into the atmosphere.

Pressing f1 takes a screenshot of just the game, so there won't be a windows border around the image. The screenshots can be found in the Screenshots folder in the KSP folder.

The GUI is the navball, stages, etc. You can hide this inflight by pressing f2 (pressing it again will bring it back) this allows for unobstructed screenshots.

Edited January 20, 2014 by Giggleplex777

[MaverickSawyer]

Hrm... might want to add a few RCS blocks to help you land gently (aka no sideways speed.)

Also, for the final orbital insertion, the engine he has will be more than enough. I've made the push to orbit on lower TWR than that. And that should be far more thrust than is needed on the Mun. So watch your throttle on descent.

[Horn Brain]

Go for a steep-ish ascent. It's not optimal, but you will probably need the extra time at apoapsis to complete your orbital insertion.

[JenBurdoo]

The RCSs are there, they're hiding behind the landing legs as the center of mass is close to that point.

What would I need to boost the TWR on any/all stages? Just adding fuel seems to be a losing proposition.

[MaverickSawyer]

Actually, just adding fuel would increase your dV, not your TWR. TWR would go down.

If you're worried about TWR, you need to add more thrust. Thus the line, "MOAR BOOSTERS!"

[UmbralRaptor]

Feel free, I'm very much a newbie here. Thanks for the comments!

If you're using stock aerodynamics, ditch the nosecones. They're slightly reducing your rocket's performance. Yes, really. Also, replace the Poodle on the upper stage with an LV-T30. The landing legs will still reach, and you'll see an increase in that stage's TWR and ÃŽâ€V(!) You'll also see smaller gains in the lower stages.

edit: Also, running struts from boosters to the lander might make the whole stack a bit more stable on ascent.

[JenBurdoo]

The LVT30 is narrower than the Poodle, and the casing that goes around it once I reconnect the parts just... is a lot slimmer than the parts above and below it. Is that going to be a structural problem (I imagine the top collapsing on an engine too narrow to hold it), or is it possible to brace it with struts or force it to cover with a casing the same size as the sections above and below?

[MaverickSawyer]

Struts will be needed. 3 minimum, 6 max.

[ddenis]

Hm, you're right. Doesn't that mean it can't take off, though? It has to be over 1.0? I suppose during TLI and landing I'll have burned some fuel though.

The TWR for Mun lander is Ok. Because Mun gravity is about 1/6 of Kerbin's. So full lander on Mun will have TWR => 5.

For such measurements you can use Kerbal Engineer Redux in which you can switch for which body you want measure TWR.

Edited January 20, 2014 by ddenis

[Superfluous J]

I'd personally drop the RCS entirely and use the dV you saved using the main engine to slow down my horizontal speed in tandem with my vertical speed on descent.

[Smidge204]

Looks like you took a stock Kerbal X and added another fuel tank. Nothing wrong with that, but I've a few suggestions.

For one, the extra fuel tank makes the lander more top-heavy, making it much more likely to topple over unless you're very careful with the landing. I would suggest using four FL-T400 fuel tanks attached radially, between the legs (increase number of landing legs to four as well), rather than sticking a X200-16 in there and making the whole thing taller. Attach them to the main central tank using fuel lines.

As a bonus, you could use radial decouplers and ditch those extra tanks once empty, which will boost your dV. Even more bonus if you use asparagus staging.

You could even stick additional engines on those tanks - I'd recommend the 48-7S for it's great TWR and quite reasonable efficiency. If using asparagus, put them only on the two radial tanks to be dropped last.

=Smidge=

[Psycix]

This is my modificaton of the Kerbal X, I call it: The Kerbal Xi

Perhaps it can serve as inspiration.

Javascript is disabled. View full album

It features an extra light upper stage which is extremely easy to land.

The upper stage contains a girder-adapter, with the fuel tanks attached radially.

This allows me to use a center decoupler, while running a multitude of rockomax engines.

I also avoided the huge, ugly and heavy decouplers at all cost.

I have the craft file somewhere if you want it.

Edited January 20, 2014 by Psycix

[Tank Buddy]

It can't hurt to try. That's how I learned to eyeball if things had enough Delta V.

[LarryWallwart]

I find landing on Mun very tricky. especially with top heavy landers. They always tip over as I am landing. It's very easy to land on the side of a steep slope. My landers look more like this. I use 3 legs instead of 4.

[Superfluous J]

I find landing on Mun very tricky. especially with top heavy landers. They always tip over as I am landing. It's very easy to land on the side of a steep slope. My landers look more like this. http://i40.tinypic.com/313hdzd.jpg I use 3 legs instead of 4.

You should also use 1 engine instead of 4 (or 3).

[UmbralRaptor]

The LVT30 is narrower than the Poodle, and the casing that goes around it once I reconnect the parts just... is a lot slimmer than the parts above and below it. Is that going to be a structural problem (I imagine the top collapsing on an engine too narrow to hold it), or is it possible to brace it with struts or force it to cover with a casing the same size as the sections above and below?

No problem whatsoever. Due to game engine limitations, mass above a part matters far more than width. (See also: why adapters are only of aesthetic use without FAR)

[Taki117]

SNIP

I have the craft file somewhere if you want it.

I just want the Lander Part (if you want to toss in the rest of the ship that's fine too)

[Rickenbacker]

It'll easily land on the Mun and take off again, that takes less than 2000 Delta-V. But the TWR on your launcher is a bit low, you might add some solid boosters to get it going.

[JenBurdoo]

Well, the modifications are going well so far, but I am concerned about, as several people have mentioned, the lander tipping over. However, I haven't learned to set up fuel lines yet. Would it be possible to attach the landing legs to girders sticking out from the body of the craft? How likely would they be to break?

[Rickenbacker]

They'd probably hold. But fuel lines aren't very hard to use. Just click once on the tank you want the fuel to flow FROM, then once on the tank you want the fuel to flow TO. A fuel line will be created, with arrows showing the direction of flow. Works with symmetry too.

[MajorThomas]

Well, the modifications are going well so far, but I am concerned about, as several people have mentioned, the lander tipping over. However, I haven't learned to set up fuel lines yet. Would it be possible to attach the landing legs to girders sticking out from the body of the craft? How likely would they be to break?

I have not had any trouble with landing legs on the outside of girders. It does make the lander more stable. I would try to limit my landing speed to less than 5 m/s regardless, doing so will very likely not harm the girders/legs.

I would, however, use appropriate landing legs. For example, if you have a small lander, there's no reason to have 4 large landing legs (unless you really like how they look and fold up). Use as few legs, and the lightest legs possible. If going to the Mun and you are able to land at a low speed, then use medium or small legs. The weight savings will really pay off in higher TWR and delta-V.