Return soil samples from Mun?

[Stealth17]

Hey guys,

I've progressed quite a bit in the tech tree, but I just can't seem to get soil samples from the Mun back to Kerbin.

Here's a screenshot from my techtree:

I've tried several different designs, all of them rockets. SSTO's can't refuel anywhere yet so mine can't get to the Mun yet.

Here's my ultimate goal: have a lander which can bring back several different samples from the Mun to Kerbin.

If anyone could help me with pointers or a design that'd be great .

Best,

Stealth

[MrPopcup]

lol, Can't you make a rocket capable of going to the mun and back? I've only unlocked half what you've got and I've already been to the mun and back also minmus ( I'm an old player btw, just for you info )

but ok, I will see what I can do with you !

About samples, you can only take ONE sample per kerbal, and you only take samples while on EVA. keep in mind that probes can't take samples,too.

[Stealth17]

Hence the question MrPopcup; how should I do it? .

[Crush]

A return mission from Mun is possible on a much lower tech level.

A rocket consisting only of a parachute, a command pod, a FL-T400 fuel tank (full) and a LV-909 engine has enough power to get from the Mun surface back to Kerbin.

To get it full to the surface, you could attach some tanks to it with radial decouplers which you leave behind on the surface. You can also attach the landing legs to the tanks, because you won't need them anymore after leaving the surface.

Note that you can only return a single soil sample per command pod and biome. But you can "suck a biome dry" by repeatedly collecting a sample and transmitting it.

Edited October 18, 2013 by Crush

[Stealth17]

What do you mean it's strong enough? That's not including getting into orbit is it?

God I feel like a noob, and that with over 200 hours into the program

[Quaiden]

I suggest you watch this video from Scott Manley...

http://youtu.be/ZNXTFj3ozNY

[Dave Kerbin]

For reference, here is my Mun ship which was a bit over engineered since I only did the rough math and errd on the side of caution. It got me to the Mun with plenty of fuel for a safe touchdown and return. I was able to collect soil samples, perform some additional experiments and relay a few crew reports during the trip.

http://forum.kerbalspaceprogram.com/threads/53159-Science-leads-to-wonderful-things?p=707046&viewfull=1#post707046

And here is the tech tree I had. Now technically an experienced player can do a Mun mission without unlocking anything, but that requires some jerry-rigged decouplers and enough skill to land on an engine safely. I've marked the suggested techs. Survivability is the key one, as it gives you landing gear and the LV-909 engine, I wouldn't do a Mun landing without them. Stability is the next most useful for the radial decoupler which makes efficient booster stages easier (you can jerry-rig radial decouplers out of more basic parts though). General Rocketry gives you a thrust vectoring launch engine along with the bigger solid boosters. Science Tech gives you batteries and the Science Bay Jr which can add more science value to the mission.

I'd be willing to help you, but I need to know what part of the mission is holding you back.

-Can you get into stable orbit around Kerbin?

-Can you plot a course to the Mun? (you enter the Mun's sphere of influence)

-Can you get into stable orbit around the Mun?

-Can you land safely on the Mun?

-Can you launch back into Mun orbit?

-Can you plot a course to bring you back to Kerbin orbit?

-Can you descend safely to Kerbin?

[Godot]

Considering the fact that you already unlocked LV-Ns (and, I assume, Skipper engines as well), it should be rather easy ...

Skipper engines and large tanks to get from surface to Orbit, LV-Ns and enough tanks to have a dV of ~1000-1500 to get from Kerbin to munar orbit,

then one or more LV-909 + ~2000-3000 dV for your landing and return stage

That should be generously dimensioned enough to cover up all eventualities

[Stealth17]

Thanks for the feedback guys . Watching Scott's video now.

-Can you get into stable orbit around Kerbin? Yes

-Can you plot a course to the Mun? (you enter the Mun's sphere of influence) Yes

-Can you get into stable orbit around the Mun? Yes

-Can you land safely on the Mun? Yes, most of the time - except when I land in the dark

-Can you launch back into Mun orbit? No - out of fuel

-Can you plot a course to bring you back to Kerbin orbit? No - out of fuel

-Can you descend safely to Kerbin? Yeah, but only did with craft (SSTO/Rockets) which have been in orbit around Kerbin, no further

[Dave Kerbin]

-Can you launch back into Mun orbit? No - out of fuel

The first thing I'd do is make sure you're not trying to land an enormous rocket on the Mun. Pre-0.22 a lot of people got used to building massive rockets (moar boosters! moar struts!), but in reality a bigger rocket just makes things harder because of how fuel works. If you need to carry more fuel to lift a bigger rocket, you need to carry exponentially more fuel to carry that fuel. If you aren't doing it already I would make your return rocket as small as possible. You can see in my pictures I have an LV-909 engine, T400 fuel tank (180L of fuel), my science experiments and the pod (along with landing gear and parachutes). With that 180 fuel and a 390 isp engine you can deorbit a 5 ton ship, land on the Mun, take off and return to Kerbin with fuel to spare. Because my orbital stage still had fuel I used it for the deorbit burn, giving me even more fuel in the lander for safety.

If you know how to do delta V math I would build a booster stage or stages with a combine delta V of 3500m/s, an orbit stage with 2000m/s and a lander with another 1900m/s. The lander design I've already told you about has that delta v, and the orbitor would be an LV-909 engine, 2 T400 tanks and a single T100 tank with decoupler.

[Stealth17]

I always used MechJeb to see how much TWR and Delta-V I had. Unfortunately I can't use that with the career mode so I'm a bit lost there.

Thanks for your excellent tutorial/mission report Dave!

[magnemoe]

This, my current Mun lander is a one man lander can, material lab and a 909 engine. I have four 90 liter tanks on the sides of it with fuel pipes to the engine.

Two specimen containers, three parachutes, four medium landing legs and 1x6 solar panels, 6x400 batteries and all the small science stuff.

To get from LKO to Mun i have four 45 liter tanks I drop before entering mun orbit.

I might switch to 4x90 liter drop tanks, then I will drop them during deorbit burn and will be able to do more than one short suborbital jump.

To up to LKO I used 6 large SRB as first stage, skipper and large and medim 2.5 meter tank.

[aeroz]

I was wondering something similar to what's discussed here. If I were to do this Apollo style - i.e. a lander and command module - can i collect samples from the moon, return to lunar orbit, and then return in the command module with the samples? or does it all have to be done with the same craft?

I haven't tried it yet, I just transmitted the science back before. But figured i'd ask.

[MonkeyFuzz]

I was wondering something similar to what's discussed here. If I were to do this Apollo style - i.e. a lander and command module - can i collect samples from the moon, return to lunar orbit, and then return in the command module with the samples? or does it all have to be done with the same craft?

No, that's not something that's possible yet. The soil samples currently stay in which ever module they were first brought into and stay there permanently. When you land on Kerbin in only your command module, the samples are not with you.

Additionally, the science bonus for returning in a vehicle that landed on a new body is not carried over because you aren't returning that lander to Kerbin.

In my Mun missions, I've modified my approach to bring the Munar ascent stage back to Kerbin (having added extra parachutes to the CM capsule to account for the added mass). The only real trick (since my CM has more than enough delta-v to break munar orbit and return to Kerbin's atmosphere) is to use the Munar ascent engines while descending to Kerbin to brake sufficiently so that when the parachutes deploy at 500m the contraption isn't torn apart. Slowing to <60m/s has been enough to allow a safe landing of my combined CM capsule and Munar ascent stage.

[Camelotking524]

At the moment, you cant transfer experiments from command pods. There is a mod that will let you do that. I personally haven't used it. I just ended up rescaling one of the storage crates that came with KAS and added the function for storing experiments to it. There is also a mod that adds a part that does the same thing.

[Queeg]

-Can you launch back into Mun orbit? No - out of fuel

-Can you plot a course to bring you back to Kerbin orbit? No - out of fuel

-Can you descend safely to Kerbin? Yeah, but only did with craft (SSTO/Rockets) which have been in orbit around Kerbin, no further

I'm pretty new to all this myself.

Not quite sure what to suggest about running out of fuel to the point where you can't take off from the Mun again.

But I can point out that when flying off the Mun surface, you probably want to get into a low circular orbit and then create a maneuver node to accelerate in such a way that your exit path from the Mun is parallel to the Mun's orbit itself, but backwards in the opposite direction than the Mun is travelling. From what I can tell from watching Scott Manley's videos, this is the most efficient way of getting back into a Kerbin orbit.

Personally, when I'm setting up the maneuver node, I keep an eye on "next" orbital path once we leave the Mun's sphere of influence to watch the Kerbin periapsis and try to make my Mun escape burn put me in a Kerbin orbit that might graze the atmosphere (about 50-60k... I could be wrong - but below 70k anyway). That way, if I still end up running out of fuel, the orbits around Kerbin will slow me down each time I fly through the atmosphere so that eventually it'll bring me down and I can rely on the parachute.

As for getting there, etc. I can only recommend looking at the top speed and ISP of each engine. The higher the ISP, the more efficient the engine. Some are good in atmosphere (ie. lifting off from Kerbin), others are better in space (in a vacuum). Personally I go with a multistage rocket with ever smaller fuel tanks and engines. That way, I'm using the smallest, lowest power engine (and hopefully most efficient) to land on the Mun, with enough fuel to get me back into Mun orbit and then finally back into Kerbin orbit.

Edited November 28, 2013 by Queeg

[Eric S]

I always used MechJeb to see how much TWR and Delta-V I had. Unfortunately I can't use that with the career mode so I'm a bit lost there.

Thanks for your excellent tutorial/mission report Dave!

Try Kerbal Engineer Redux, and maybe one of the mods that add KER functionality to all command pods. With or without the extra mod, you can get delta-v readouts starting on your first mission.

About samples, you can only take ONE sample per kerbal, and you only take samples while on EVA. keep in mind that probes can't take samples,too.

While strictly true, the capsule is capable of storing multiple surface samples as long as they're of different biomes. I've returned 15 surface samples in a single Mun mission.

As to the main purpose of the thread, I find the trick is to be choosy about overbuilding the craft. For example, this is my multi-biome Munar lander. It has enough delta-V that I can usually hit 4-6 biomes in a single mission and is usable far earlier in the tech tree than you are now (the only tech it uses that you don't have are the folding solar panels, and you can easily work around that). The four radially mounted fuel tanks are chained drop tanks, so I drop the first two as soon as they're empty, and the other two when it's time to go home (and they're empty). The center stack as enough fuel to return the craft to orbit and put the craft into an aerobrake return to Kerbin, provided the drop tanks have been dropped. As you can see, that's over 10k delta-v, which is serious overkill if you're not planning on suborbital hops to go to multiple biomes. Though definitely do suborbital hops rather than a full return to orbit then landing, that will take over twice as much delta-v per hop. Heck, I even do most of my initial landing using the transfer stage, dropping it only when I have to so that it won't be under me when I land.

I think you'd have to be really meticulous to have any chance to even get close to 15 biomes with that craft, however. My other multi-biome Munar lander takes a slightly different approach. The lander is a multihop lander/rover combination, so it drives to biomes that are close, hops to those that are farther away. This is the one that I've hit all 15 biomes in a single trip with, though it takes a lot of driving to pull that off. This one uses the same technologies as the first one plus wheels, so it often isn't my first Munar lander in any particular career mode save.

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