Collecting science from the Mun (2024)

That's certainly in the spirit of my trying to minimize launches, good idea Collecting science from the Mun (1)

What does your lander look like? Mine is already having a hard time landing from and getting back into a 35 km Mun orbit, I'm sure there's lot of room for improvement there.

Pictures:

https://dl.dropboxusercontent.com/u/44754370/screenshot14.png - Stack of three landers inside the fairing of the Munraker XI rocket

https://dl.dropboxusercontent.com/u/44754370/screenshot15.png - On the launchpad, right side with thermometer and communotron

https://dl.dropboxusercontent.com/u/44754370/screenshot16.png - On the launchpad, left side with gravioli detector and accelerometer

https://dl.dropboxusercontent.com/u/44754370/screenshot17.png - On the launchpad, front with landing spotlight and life support canister

Now obviously this was done with some mods installed. However, the basic principle is still valid with stock parts. You want a low center of mass and a wide stance, so that you don't risk tipping over on landing. Thus I put the lander can in the bottom middle and used quad side-mounted fuel tanks. They have little engines at the bottom, which takes less space than one central engine below the lander can. Up top I put the materials bay and the goo canister. That latter one requires some tinkering, because it unbalances the craft. I ended up using the life support canister as a counterweight on the other side, but if you play without mods than you'll need to find a different solution for the off-center weight (possibly work with the parachute placement). Obviously if you only have one lander you can put the goo canister on top, but with stacked landers you need that spot for a decoupler. Notice how the decoupler is flipped upside down, so that it sticks to the underside instead of to the top and thus contributes to keeping the center of mass low.

My landing legs look a little funny because I needed to fit them inside the diameter of the fairing. With stock parts you don't have that problem and can mount them however you want.

I'm using two mini-RTGs for power; without mods, put solar panels there. One on each side is plenty, as the only thing that consumes power on this thing is the reaction wheel of the lander can. The antenna can be used to transmit crew/EVA reports so you don't have to wait for the return, but ultimately it's optional.

For engines, I think that lander has a grand total of either 20 or 24 kN of thrust; I forget if each engine was 5 or 6. But the point is, you can work with the Rockomax 48-7S here and easily get away with only using two engines (even that will give you 60 kN, almost three times what my lander has). Mount them diagonally and use fuel lines to feed fuel from those tanks that don't have engines into those that do. It will still be symmetric.

Now, the fuel tanks can get somewhat annoying with stock parts because you don't have a proper elongated 0.625m tank. You'll have to stack Oscar-B's. Also try and make use of the toroidal tanks on the ends, they have less dry mass per fuel, meaning you get more dV. As for how much fuel you'll need in total, you need to experiment as the mass ratio and engine Isp will be different from my configuration.

The most important part to save fuel though: don't bother with a 35km orbit, that costs too much fuel. The highest elevation on the Mun is 7km high, so an orbit between 8km and 10km is perfectly sufficient (and maximizes what little Oberth effect the low gravity can give you). Then comes knowing how to return to Kerbin in the most efficient fashion: circularize at that altitude in an orbit that intersects the points where the Mun's own orbit lines hit the surface. In most cases, that works by launching towards the 90° heading, no matter where you are on the Mun (but practice this). Then make a maneuver node to plan your ejection burn, and eject fully retrograde. This should be the last burn you need to perform, as you can get your Kerbin periapsis to ca. 30km directly from that maneuver node. Moving the node itself around helps you find the position where this costs the least amount of dV.

Then you just coast home and perform reentry. Two radial parachutes slow the craft down for landing.

Notice the two little fuel tanks stacked on top of the long ones, though? Yeah, that was necessary after the first trial run revealed that I was short on fuel. This design really is cutting it close for the Mun, and I need to pilot it properly to get it home. Don't be afraid to throw a little more fuel at the problem just to be safe, you have more engine thrust anyway. On Minmus, this lander works quite comfortably because it needs less fuel to land and return.

(Mods used: RLA Stockalike, RLA Power Generation and TAC Life Support. For the Munraker XI, also KW Rocketry. I am proud to say however that no part clipping is required whatsoever.)

Edited by Streetwind

Collecting science from the Mun (2024)

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