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Finding flat spots?


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I've been playing for a long time, but I've never really figured out a good way to find spots that are actually flat and level to land on, especially on the Mun. Does anyone have a good technique, other than bring enough extra fuel to be able to skip around for awhile once you get close to the ground?

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You can use a map like https://ksp.deringenieur.net/ and use the slope setting to pick out a relatively flat location and then try to land at those coordinates. You can also use Kerbal Engineer Redux to give you a reading of the surface slope information below your vessel for possible landing sites. 

Or you can use a mod with a mod like Throttle Controlled Avionics. It has a landing routine that evaluates your selected landing location for flatness and scans around to see if there is a flatter surface to touch down on and then does it.. 

 

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1 hour ago, chd said:

bring enough extra fuel to be able to skip around for awhile once you get close to the ground?

If you're looking for a place to set up a base there's no better (stock at least) way than a dedicated probe. Give it the bare minimum of stuff and enough fuel for multiple hops, which won't be that much.

Then bring several of them along and toss them at any flat looking area you're thinking about.

They're dirt cheap, throwaway, and you'll get a lot more looks than you'd ever get trying to land your whole base and hopping around.

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19 hours ago, chd said:

I've been playing for a long time, but I've never really figured out a good way to find spots that are actually flat and level to land on, especially on the Mun. Does anyone have a good technique, other than bring enough extra fuel to be able to skip around for awhile once you get close to the ground?

A common solution to this problem is to turn it the other way around, and build a lander that's really stable so that it can land on a slope without tipping over.  Low CoM, wide / squat build.  That way you don't have to care whether the ground is especially flat or not.  :)

If you're talking about the Mun, most of its terrain is not all that steep.  Crater floors are reasonably level when you get away from the ring wall, as are the lowlands / midlands / highlands in between craters.  As long as you don't land on the side of a crater, it's usually not too bad.

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1 hour ago, Snark said:

A common solution to this problem is to turn it the other way around, and build a lander that's really stable so that it can land on a slope without tipping over.  Low CoM, wide / squat build.

I've done that before too, and it works, but it's usually pretty draggy at launch.

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10 minutes ago, chd said:

I've done that before too, and it works, but it's usually pretty draggy at launch.

Well, it depends on the design.  It's possible to build a fairly squat / stable lander whose aerodynamics during launch isn't too bad.  Here's an example of a Mun lander that's typical of the type I like to use:

x1dEiaN.png

The Baguette fuel tanks are great.  You can attach them to pretty much anything, and they're reasonably aerodynamic on ascent.  And by attaching the landing gear to them rather than to the central stack, that really widens the lander's "stance" and makes it quite stable.

And I can adjust the vertical positioning so that the Baguettes are really low down-- they're nearly touching the ground as the lander sits on its landing legs.  I've set the fuel draining priorities so that the lander drains from the top down (the opposite of what one usually does, since we're going for bottom-heavy).  The Baguettes, right down at ground level, are the last to empty.  So they really lower the CoM.

This lander can rest on a slope of nearly 45 degrees without tipping over.  It's fairly aerodynamic, and it sits comfortably atop a 1.25m stack.

Here's another variant of the same basic idea-- this two-kerbal lander is also quite aerodynamic, virtually tip-proof, and sits nicely on a 1.875m stack.

GLQY31U.png

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I hadn't thought of using the baguettes like that - good idea! I did make one *really* wide by putting the landing legs on the ends of girder pieces attached to a 2.5m stack - that worked but it was draggy. I even tried to make a version of that where the long legs supported folded up for launch using some of the robotics hinges, but those proved to be not nearly strong enough. That was before I started using KJR, which I am now, so maybe that changed.

It's mostly an issue for 2.5m rockets that are especially tall, like when a contract requires a science lab or something.

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there's no really flat terrain on mun. what i did was learning to land on sloped ground.

as long as you avoid a crater wall, you should get at most 15-20 degrees. it's reasonably feasible to make a lander that is stable at that inclination.

for challenges that prevent me from making such a lander, i just save scum a lot until i find a flat place.

 

 

as for less inclined ground, anyway, i can recommend the spot around 2° N 5° E, just southwest of northwest crater. there is a narrow strip without craters there that i found particularly convenient to aim

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3 minutes ago, chd said:

I did make one *really* wide by putting the landing legs on the ends of girder pieces attached to a 2.5m stack

Oh, goodness no-- girders are astoundingly hideously draggy, that'll make it fly like a brick.  ;)

4 minutes ago, chd said:

It's mostly an issue for 2.5m rockets that are especially tall, like when a contract requires a science lab or something.

Here's a design type I like to use for scenarios like that:

9HslMTj.png

Those side stacks are attached to the center using Small Hardpoint, which is very light and quite aerodynamic.  (There's also "Structural Pylon", which gets quite a bit more separation and is also very aerodynamic, but those are pretty heavy so I tend not to use them as much.)

Again, virtually tip-proof.  As shown, that has nearly 2 km/s of dV in a vacuum.  Quite aerodynamic.  Depending on the design of what goes beneath, the side stacks can be made aerodynamic for launch by putting upside-down nosecones on decouplers under the engines (to be discarded as soon as it's out of atmosphere), or you could put booster stacks under them.

Highly tweakable design concept depending on needs.

  • Got a contract that wants more kerbals in the base?  Make the side stacks have a much shorter fuel tank, like the 0.5t one, and put Mk1 crew cabins under them.
  • Need more dV?  The left and right sides are available-- you can attach drop tanks there.  A pair of FL-T800s (with nosecones on top and bottom) will give you 8 more tons of fuel, and still reasonably aerodynamic.

Since the center of the stack has no engine, you can attach a 2.5m droptank below the central stack (say, 8 ton or 16 ton), with the decoupler having its crossfeed enabled so that the engines can pull from it.  Of course, you can't land with the droptank below there, but it's a great way to add dV in order to, for example, eject from LKO, without having to lug around extra engines for the purpose.

45 minutes ago, chd said:

I even tried to make a version of that where the long legs supported folded up for launch using some of the robotics hinges, but those proved to be not nearly strong enough.

Note that autostruts can't cross an unlocked hinge.  Breaking Ground robotic landing legs can work, and can work just fine without KJR.  But you need a bit of design attention to them.  After extending the robotic hinges, you then need to lock all their joints.  That will allow the autostruts on the landing legs to lock on to the center body of the ship, and it'll be plenty stiff enough.

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I did the "baguette tanks on the side, then landing legs on the bags" design too. It helps to not take the kitchen sink with you too, and have the previous stage do most of the knocking off the horizontal speed (you can get speed to 0 with about 500-1000m to go, then decouple it), then you can be low and wide.

Once you have opened up the tech to include aerodynamic fairings, its not so hard to design a lander capable of slopes.

And there's always self-righting (normally you can roll around with Q and E, so one landing leg at the top would probably do it)

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