Apollo-Style Mun Mission?

[The Jedi Master]

What the title says(I know, I know, but it's always so descriptive). I build my AWESOME Apollo-style Mun lander, brought it to the pad... physics kicks in... BOOM BA BOOM BOOM BOOM. While it was one of the prettier explosions I've seen, it was a bit disconcerting...

So, how do I go to the Mun, Armstrong style? Thanks!

[Johnno]

First, MOAR STRUTS. Second, MOAR ROKKITS.

If you want specific help, pictures would help, alternatively a description or the failure reason (should get it on end flight but default is F3).

Apollo in simple terms is lander (ascent and descent stage), command module (with fuel + engine for mun insertion and mun exit burns), third stage to push you to orbit and send you toward mun and two big stages to get you started on your journey. Docking ports on lander and command module of course.

I used the analog of big red tank in the middle, 4 around it, mainsails for engines, both for stage 1 and 2, then some 2 meter tanks of varying sizes for the rest. Strut tanks to eachother, slap on some control surfaces and don't forget launch stabilizers (the tower-strut things).

And before anyone mentions that in KSP it's easier to land with a small lander and take off with the whole ship intact rather than descent/ascent stages, that's not very Apollolike.

[Sᴄɪɴᴛɪʟʟᴀᴛᴏʀ]

What are you actually asking? How to go to the moon with a lander and service module?

[The Jedi Master]

What are you actually asking? How to go to the moon with a lander and service module?

Pretty much, yeah. Always liked that green text, by the way.

[Sᴄɪɴᴛɪʟʟᴀᴛᴏʀ]

Pretty much, yeah. Always liked that green text, by the way.

Thanks

Just design the lifter to be able to carry the extra weight and add some struts between the lander and service module to prevent craft-destroying wobble.

Are you going for a saturn-v look with the lifter or does its appearance matter?

[Cryocasm]

Pretty much, yeah. Always liked that green text, by the way.

Relatively easy, lets do some math, shall we?

Assuming your lander is of the launchpad type, your going to be taking a bit of drymass for struts and decouplers with you.

Assembling the lander, we get mass of around 12.5 tons wet. This consists of 2 lander cans (the 1m one), 4 legs, SAS, decoupler, the landing engine (Poodle) and the relaunching engines 4x white radial engines.

The pod has 4 tons, + 500kg of parachutes, therefore 4.5 tons.

The service module in KSP would only host fuel, engine, RCS, ASAS, and a decoupler. Say this is about 18 tons.

Adding all of our masses, +5% struts, we get 12.5+4.5+18 tons, or ~37 tons of Payload mass.

Now, using a rule of thumb, the total wet mass on the launchpad may not exceed 10x the payload mass. This is 100% doable.

Say we duplicate the Saturn V properly, resulting in a Jumbo, RCS, 4x thrusters, and a Mainsail on the stage below the Munar Segment (lander, capsule, service module), we attain a Munar Injection Stage weight of around 80 tons, if we add in the struts. The Mainsail should provide more than 1.0 of TWR (thrust weight ratio, measured in newtons).

Now we have 77 tons. We need 77000*10 = 770000 Newtons of thrust (I simplified gravity to 10 m/s, to give leeway). 0.7 Meganewtons aren't hard to accomplish. I actually overshot quite a bit with the Mainsail, but for Apollo-ness, we need it to be launched off into space or the Mün.

So, "desirable" Kerbin surface TWR is 2.2, meaning we need the power of 2.2 total wet weight at launch. I devised a system using a Jumbo + Mainsail, 8x FLT-800s with LVT-T45s and a white radial engine on each fuel tank. This gave me a TWR of 2.23 at lift off. The final stage weighs in at 110 tons dry. This puts us at 187 tons, which is less than our rule of thumb, 10x37. Hell, this design even overachieves with nearly 1/2 the maximum wet mass, at 50.5% of the maximum wet weight, using the rule of thumb.

Some nice info from Mechjeb gives around 5.1 km/s of dV. This should suffice for a trip to the Mun and back.

[The Jedi Master]

Are you going for a saturn-v look with the lifter or does its appearance matter?

Making it look like Saturn V would just make it harder, so just the style, not the looks.

[Aphox]

http://wiki.kerbalspaceprogram.com/wiki/Tutorial:_Apollo_11

This page, while not extremely well written, gives you the blueprints of a craft that's perfectly Apollo-capable with some tweaking. I ended up adding a lot more struts than it mentioned and some girders to keep the top half from wobbling so much.

Alternatively, there's an extremely well-made mod being developed here with a 100% custom made Saturn V complete with LM and CSM. I'd give that a shot. I'm also giving it a shameless plug here because I absolutely adore it.

[Sᴄɪɴᴛɪʟʟᴀᴛᴏʀ]

Making it look like Saturn V would just make it harder, so just the style, not the looks.

The tutorial Aphox just posted looks like a winner, I'd go with that.

[Aphox]

As a note, the only beef I really have with that tutorial is that it's a single-stage lander, while the real Apollo lunar module, as I'm sure we all know, had a descent stage and an ascent stage. If you can find a way to squeeze that into that design (which doesn't fit in the VAB, by the way), let us know. I'm far too lazy to pull it off.

More reason to use the AMP mod hehe.

[The Jedi Master]

The part I'm afraid of with that tutorial is the rearrangement of the Munar lander and the service module. Looks hard. Then again, part of the reason I'm doing this is that it is a reasonably simple way to learn docking, so I'll try it.

[The Jedi Master]

When I loaded up the ship the tutorial told me to make, first it was REALLY wobbly, and then...

At least they survived, in true Kerbal fashion.

[Aphox]

I put launch clamps on the canards. If you put them directly on the fueltanks it falls apart for some reason.

Like I said, it's not perfect and needs some tweaking. I got it to work eventually though.

[Kegereneku]

This old non-optimized rocket was capable of doing it, the CSM even have more fuel than needed.

Of course it get more complicated if you get rid of Booster.

You can reduce quite the CSM fuel mass, and making a two-stage LEM can also help.

Lately I build an optimized version with less CSM fuel, two-stage LEM, Skipper engine on the Translunar stage (which have exactly 900 of Dv to match Apollo).

Although, the truth is that you don't need much to reach the mun and come back

[rhoark]

KW rocketry's 3.75m parts (with interstage fairings!) are good for making a Saturn-esque rocket.

[Nimelrian]

If you're not afraid to use mods, check out my journey to the Mün, which was inspired by the Apollo program (I did tweak some of the details to make it work though). Used KW Rocketry, Mechjeb and KSPX.

http://forum.kerbalspaceprogram.com/showthread.php/31094-To-the-M%C3%BCn-and-Back!-A-KSP-story-in-60-pictures

You can get the craft here: http://pastebin.com/k8BHK9t9

[Temstar]

If there's no requirement to closely mimic the Saturn-V stack itself then I've made an Apollo style craft using all stock parts:

http://forum.kerbalspaceprogram.com/showthread.php/28133-0-20-Apollo-style-spacecraft-Apokee-MS