Crash landing

[Foxster]

What are the issues with litho-braking? Just how fast can you hit the dirt on an airless body? Anyone messed around with this? Can you survive, say, Moho with no insertion burn but just fly right into the surface?

I was looking at parts. I see the Structural Pylon has the highest crash tolerance of 999m/s. If I coat a capsule with these can I hit the ground at 999m/s or will the parts inside break up?

[Mad Rocket Scientist]

Generally the joint strength in weaker than the impact resistance.

(Tests are clearly needed, however)

[Foxster]

Generally the joint strength in weaker than the impact resistance.

(Tests are clearly needed, however)

Clearly. Enquiring minds need to know.

Not going so well so far. Lots of flame, not much fame.

[Hodo]

If you are coming without slowing down.... that will end up in tears. But as a whole you can hit the ground pretty hard in some cases. Fastest I have hit at 15-25m/s.

[Starhawk]

Lander legs might be your best bet. They're designed to absorb a fair bit of energy before breaking.

I just tested a Mk1 Lander Can with a Toroidal tank and a 48-7S equipped with four medium lander legs.

It survived an impact in excess of 88 m/s in my test.

Happy landings!

edit: 99 m/s however, led to Bartble's demise in the simulator.

Edited April 2, 2015 by Starhawk

[Foxster]

Umm, looking for more like 30,000m/s . Or am I being a tad optimistic?

[Starhawk]

Maybe a really big crumple zone...

[Foxster]

Maybe a really big crumple zone...

How about a class-B asteroid?

[Slam_Jones]

Maybe a really big crumple zone...

I'm thinking alternating stacks of vertical I-beams and 2x2 structural plates might be able to "crumple" (explode) the right way

[Randazzo]

Wrap your vehicle in kerbal helmets.

Kerbals can survive free falls from orbital altitudes if they land on their head.

In all seriousness, you're going to run into problems with clipping through the terrain if you really try to impact at ridiculously high speeds. Even if you survive the actual impact, if you clip through the ground, you'll explode anyway.

[vsully]

I often land Kerbal aircraft on retracted Small landing gear bays. They hold well, but on larger aircraft I make stock shock absorbers with those small square things (Imma so sorry i forget what they're called) and they hold up well on 50-60m/s landings.

[Foxster]

I'm thinking alternating stacks of vertical I-beams and 2x2 structural plates might be able to "crumple" (explode) the right way

Cunning plan. Did I mention the crash resistance needs to weigh less than 1/2t?

[Starhawk]

Cunning plan. Did I mention the crash resistance needs to weigh less than 1/2t?

There's the rub. I just combined some girders and structural panels with some heavy lander legs, and survived a 215 m/s impact with the Mun. But even this little setup masses several tonnes.

Happy landings! (or should I even say that?)

[Foxster]

There's the rub. I just combined some girders and structural panels with some heavy lander legs, and survived a 215 m/s impact with the Mun. But even this little setup masses several tonnes.

Happy landings! (or should I even say that?)

Sounds good. Got a picture?

[Starhawk]

Sounds good. Got a picture?

Here ya go. I had to use a Mk1 Cockpit due to the higher crash tolerance. The Mk1 Command Pod worked fine on most of the tests, but there was one very bad tumble which required a somewhat higher impact tolerance.

Happy landings!

[StrandedonEarth]

Here ya go.

http://i.imgur.com/t89V7B1.png

Happy landings!

Nice design. Now how's he gonna get home?

[Starhawk]

Nice design. Now how's he gonna get home?

What!? I thought this was a colonization mission...

Happy landings!

[StrandedonEarth]

What!? I thought this was a colonization mission...

Happy landings!

Riiiight, I forgot. Every crash landing automatically becomes a colonization effort.

[Foxster]

Looks good. To handle spinning about on landing I guess that would need to be made 3d. And perhaps use massless part...umm...

[Starhawk]

I just kept the legs pointed down. There is tumbling and stuff after the legs explode, but the cockpit can handle up to 45 m/s impact. You just need to dampen that initial impact.

Cubic octagonal struts maybe?

[Foxster]

I just kept the legs pointed down. There is tumbling and stuff after the legs explode, but the cockpit can handle up to 45 m/s impact. You just need to dampen that initial impact.

Cubic octagonal struts maybe?

Yup, just what I was thinking...

[Starhawk]

Very much the sort of thing I was imagining. I'm quite curious how it will perform.

Happy crashings!

[Foxster]

Very much the sort of thing I was imagining. I'm quite curious how it will perform.

Happy crashings!

Large part count though

[Foxster]

Its very effective on bodies with an atmos. All those parts and their drag means you can't seem to land at any more than 100m/s no matter how high you start from. But that wasn't really the aim here, I wanted to get something that would survive an unpowered de-orbit at least (say 600-1000 m/s) on an airless body. Just tried it on Moho and my poor Kerbal was smeared to about 0.5mm thick. Which probably stung a bit.

[TheXRuler]

30000 m/s might be just a tad optimistic, although I do really like the idea of smashing a thousand part vessel into mohos surface at 30km/s definetly the most kerbal way to get there ^^

If you really want to try this you could build legs out of cubic octagonal struts, since they are ridiculously tough and also very flexible when used in large amounts. However hitting the ground at very high velocities can result in quite other problems, as Randazzo has already said if you are going fast enough you will be about to crash in one physics frame, in the next you will be below the planets surface causing you to explode, though you might just be able to counteract this with a VERY large vessel. Scott Manley had to deal with a similar problem in his video

.

I must admit this is all just random theorizing, I have very little experience with lithobraking, mostly it was accidental.