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Lander Construction


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From a Thread in general discussion Millitron suggested to not bring so much to the Mün. That way escaping Munar gravity/orbit costs less fuel.

Dont bring so much to the moon. Your lander is so heavy; that\'s your problem. Be sure to have the lander legs on decouplers, so you can drop them on lift-off. Also, cut out as much else as you can.

Now for my lander I\'ve been using the Silisko Edition

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As you can see it\'s pretty minimalist in nature.

So obviously I need to work on my rocket design and include a lunar descent stage that will get my lander slow and low enough to make a stable landing without burning a lot lander fuel (but rocket design is another topic).

As it stands now by the time I land on the surface of the Mün I have less than half a tank of fuel left and a few of the RCS nodes left which isn\'t enough to get off the rock and back home.

So what goes into your lander?

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Attached is my Aquarius Lander and a full mission report\'s on my DeviantArt account (link in profile).

From the start I wanted to include the habitation module (centre) to give my Astrokerbs the maximum time on the Mun\'s surface (yeah I know there\'s no actual need as yet but it made sense to plan ahead). And I wanted to be able to return that habitation module to Kerbin too. This extra weight and length influenced the design from the start. It would need a lot of delta-V and one heck of a lot of parachutes for a safe landing.

Trying a conventional stack of parts quickly made for a dangerously tall and thus unstable lander and trials (oh gods the trials.... :o ) revealed that any mission was likely to end with the lander falling over. So a squatter, lower design was needed and with fuel tanks bolted on the sides the height issue was solved. The Aquarius is the result of surprisingly few changes to that initial concept, mostly fine tuning the RCS position so it can kill horizontal speed as easily as possible.

One thing I learnt during Kerbin trials was that the RCS tank does not like anything on top of it when landing, it was a point of repeated failures, hence it\'s position at the bottom of the lander. A second issue was the sudden \'yank\' opening the \'chutes would give Aquarius, so the \'chute on the nose of the lander is opened first to stablise it and then the rest of chutes are deployed. The yank is still there but reduced, and a modification to the staging now deploys the remaining \'chutes in pairs so the maximum g-force\'s the lander experiences is below 3.5g.

With careful control enough fuel will remain in the lander to enter orbit over Kerbin and de-orbit close to the KSC (though using RCS to help is often required). I\'m usually a little more 'enthusiastic' so haven\'t quite managed it yet :P

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I don\'t have a joystick, so landing can be kind of difficult for me, since if I use RCS, I have to manage WASD and all the RCS controls with only my keyboard. So I try to use as light a lander as possible, so its easy to steer, and I also use most of my TLI stage as the descent stage as well, dropping it about 200m from the surface, so I don\'t use much lander fuel with the landing itself, and can then use it for the return trip. Last, I decouple my lander legs just after liftoff to save weight, so I don\'t waste any return stage fuel hauling pointless lander legs.

My landers just consist of the stock pod with stock chute, the lightweight decoupler from Nova\'s pack, the stock LFT with the weakest LFE from either Sunday Punch\'s pack, or Nova\'s pack (I can\'t remember which, and can\'t check right now). Last, it has 4 stock radial decouplers, with the controllable winglets on the ends of them, to use as ad hoc lander legs. I survive almost all my landings. So far, since I\'ve settled on this design, my only crashes have been because I wasn\'t paying attention.

I would LOVE to get a larger lander though, especially one capable of leaving a payload on the Moon\'s surface, but landing anything bigger without RCS is proving very difficult.

Edit: I\'ve attached my best lunar rocket, if anyone cares to see it. I get the sense that a lot of people think you absolutely HAVE to have ASAS and RCS to land on the moon, but that\'s simply not the case. I\'m not even all that great of a pilot, and I can do it pretty well.

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  • 2 weeks later...

I took a much more kerbal solution to dealing with the lack of fuel to get home on my original lander: more thrusters (and more fuel). Although, one should note that getting this bad boy to the moon required even more thrusters. Jeb would be proud.

However, I would not recommend this as a design to follow, the main problem being that the weight of the shuttle meant the legs were quite fragile on landings.

I would LOVE to get a larger lander though, especially one capable of leaving a payload on the Moon\'s surface, but landing anything bigger without RCS is proving very difficult.

I did not have to use any RCS outside of the initial stage and orbiting Kerbin. The RCS thrusters visible on the lander were only used in the stages mentioned earlier.

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Heh I am surprised those 2 lander engines can slow that big tank down, actually. Nice!

Since we can\'t rendevous, I am using my kerbin departure and munar orbital stage to do the heavy lifting of the landing as well, leaving the actual lander for the last 10k or so and crashing the rest of it into the mun.

In the landing screenshot, I had actually used too much fuel due to messing around, and didn\'t quite have enough to return - probably would have it I had been able to drop those legs. Guess I should make them decouplers, huh?

(probably not, since we may get an actual landerleg partclass soon)

Jd9EF.jpg

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Pretty handsome ship, if I say so myself (and I do)

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I tried to make my lander adaptable and simple. It has a descent stage with an efficient engine and two fuel tanks, one for the initial descent and one for the final approach. After the triumphant celebration of touchdown and the obligatory screenshots, two radial SRBs fire which give the ascent stage quite a lot of speed and propel it back towards Kearth. Any further orbit corrections are done with a small tank and liquid-fueled engine. This has made a successful landing and an almost successful return, failing only when the parachute was torn off during atmospheric re-entry. I\'d like to think that I accomplished something, though.

moonSUCCESS.png

As you can see if you look at the fuel gauge, it\'s not the most efficient design in that I landed with maybe a few drops of fuel left in the tank.

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I tried to make my lander adaptable and simple. It has a descent stage with an efficient engine and two fuel tanks, one for the initial descent and one for the final approach. After the triumphant celebration of touchdown and the obligatory screenshots, two radial SRBs fire which give the ascent stage quite a lot of speed and propel it back towards Kearth. Any further orbit corrections are done with a small tank and liquid-fueled engine. This has made a successful landing and an almost successful return, failing only when the parachute was torn off during atmospheric re-entry. I\'d like to think that I accomplished something, though.

moonSUCCESS.png

As you can see if you look at the fuel gauge, it\'s not the most efficient design in that I landed with maybe a few drops of fuel left in the tank.

Actually, it\'s very efficient because you landed with very little excess fuel!

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I ended up flying too much to the moon in that my second stage managed to get me to orbit and part of the way through my TLI burn, and then my NERVA TLI/Descent stage managed to land me on the moon iwth enough fuel left to return to lunar orbit and boost me to kearth return.

I didn\'t actually have to fire my ascent stage (which would have ditched pretty much everything put the pod, a lightweight decoupler and the chute)

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I ended up flying too much to the moon in that my second stage managed to get me to orbit and part of the way through my TLI burn, and then my NERVA TLI/Descent stage managed to land me on the moon iwth enough fuel left to return to lunar orbit and boost me to kearth return.

I didn\'t actually have to fire my ascent stage (which would have ditched pretty much everything put the pod, a lightweight decoupler and the chute)

Since there\'s no economy in the game yet, there is no such thing as flying too much to the moon, so long as you can still accomplish whatever it was you were doing.

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So the tanks drop off instead of having a dedicated descent stage?

My Mun base does that, though not with the fuel lines (0.12). It stays as a solid object for future cremation/ burial/ abandonment use. :D

(Bill\'s been ordered to fix the busted leg)

But the drop-off tanks with a single engine would work very nicely!

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Nova\'s parts are mostly my Go-To for landers. I\'ve started using the Mei-Long from DownUnder as an ascent/return stage. The two are great.

This one even fits under a 3m fairing.

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I like these legs better, but they\'re big. Can\'t wait until they fold up! If you make something like this that collapses when that option is available, Nova, I probably won\'t ever use another leg!

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