Dock Orbiters that are in diffrent orbits

[RuBisCO]

The challenge is simple enough: Have an orbiter in a circular orbit and another coming up to it in an eccentric Hoffman transfer orbit, now without matching velocities try to have the two orbiters dock. Now yes you might say this is impossible (actually that all you have said so far), but I tell you its not only possible its rather fun (Like running face first into a tree and not being injured fun).

Here we see the kind of orbits I've been able to do it with:

Now again very simple: when the two crafts approach each other, (1) your NOT going to dock with RCS (NO RCS!), and (2) your NOT going to use thrusters of any kind. You need to find a way to dock them together and negate all that extra kinetic energy.

Requirements:

# Approach velocity above 5 m/s

# Need to dock in the end with STOCK docking ports

# All mods are fair game, within reason (no hacks around the physics or unpublished modifications)

Scoring:

+1 points for every 1 m/s in your approach velocity.

+3 points for every 1 m/s in approach speed beyond 25 m/s (simply because I have not tried beyond that speed yet)

+10 points if you find away to do it without KAS!

-10 points if parts break off or explode.

+1 point for every ton of total mass slamming together beyond 20 tons

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Edited September 30, 2013 by RuBisCO

[boomerdog2000]

Without matching velocities the 2 craft are going to slam into each other and probably be destroyed.

Any KAS winches would be ripped off.

[JumpsterG]

This isn't formatted well as a challenge according to the forum rules, but I thought I'd add to this nonetheless:

What you're actually asking is, assuming docking ports are perfectly lined up, what happens when one touches the other at a very high relative velocity. Does it connect in a peaceful manner followed by a normalized acceleration applied to both objects... or just boom? My guess is boom.

Using a KAS grapple while passing an object at high speed sounds like fun, and will likely result in space nun-chucks accompanied by more boom.

[EDIT] OP updated challenge with rules and some proof of concept. Legitimate docking still sounds silly, but catching a passing spacecraft sounds like fun!

Edited September 30, 2013 by JumpsterG
OP updated challenge

[Superfluous J]

We have a word for docking at high velocity. It's called crashing.

[Halsfury]

I did this once, I came within 5m of my nuclear drive section to deliver fuel, however I was late on the burn and smashed right through 5 or 6 solar arrays and tore some batteries and crud off the sides of both vessels and this was only at 20m/s and with the most precise aiming I could muster (looking at the navball and not at the nuclear drive section rushing towards me)

Everything had to be de-orbited

Truth be told any attempt at high speed docking would not be able to exploit a physics bug where the two objects dock and then get their velocity vectors added together neatly, the probability of lining up perfectly at those speeds is very small since the docking port is only 1.25m across, like many things in space it's a case of shooting one bullet with another bullet while intoxicated or otherwise impaired, moreover the outcome of a direct hit is not something to be desired.

Edited September 29, 2013 by Halsfury

[Captain Sierra]

Wasn't this closed down once already because it's effectively impossible? I think it has already been established that the percision required is beyond even that of MechJeb and the result would be quite explosive.

[Jodo42]

Why is this open again. It's impossible, it's already been established.

[Pds314]

This is like asking someone to kiss someone from airplane to airplane when the airplanes aren't speed-synced, sure, it is possible.... for a split second before both people are decapitated.

[Pds314]

Please, RuBisCO, enlighten us as to how preciselly we are supposed to dock things moving at dramatically different speeds without one or both of them being torn to shreds, because as far as i'm concerned, this is like trying to catch a bullet with your teeth.

[karolus10]

Challenge can't be done... game not allow docking with high speed (no more than ~2m/s).

Please read challenge submission rules, thank You !

Thread closed.

[sal_vager]

RuBisCO claims he can do it, I'll let him show you

[DaveofDefeat]

The little challenge that could.

Its been reopened what 2 times now?

[RuBisCO]

If you still don't believe me I guess I'll need to make a video. Need to download some video software first, anyone know where I can find a free screen-to-video program?

[Halsfury]

Ok I understand, maybe this is possible in some circumstances where your plane synced with you target and you have an orbital distance greater than the altitude of minmus where small speed changes effect great changes in the orbital path

I guess that at some point even a normal seeming docking procedure could wildly alter the orbit of both craft

[RuBisCO]

Technically it should be possible as long as the target velocities are below the speed needed to cause structural failure upon impact of specific parts, so far that appears to be beyond 25 m/s for KAS parts at least, so any orbit will do as long as the vehicles are approaching each other at relatives speeds of <25 m/s. Orbit beyond minmus though provide the most dramatically different appearance, that all.

[Scarecrow88]

Irrespective of the fact that your craft start off in different orbits, by the time you are close enough and slow enough to actually dock, your orbits are in fact matched. That's how it works, because if the orbits weren't matched the velocity differential between the craft would just lead to a big explosion when they met.

My biggest offset in starting orbits was a craft that was in an eccentric orbit with Peri near Kerbin's orbit, and Apo out near Jool. I had to send a refuelling tanker, that started off in a 85k circular orbit around Kerbin. There's no way those two would have been dockable without matching orbits at some point in the proceedings.

If you reckon you can do it without matching orbits, take a screenshot just before the craft dock, showing relative velocity, followed by a second immediate screenshot of the map view, showing the orbits of the two craft.

Edited September 30, 2013 by Scarecrow88

[Captain Sierra]

It appears his plan is to anchor to the other craft with KAS, which really isn't docking. THe OP should thus be updated citing that KAS is a legal form of "docking".

[RuBisCO]

Irrespective of the fact that your craft start off in different orbits, by the time you are close enough and slow enough to actually dock, your orbits are in fact matched. That's how it works, because if the orbits weren't matched the velocity differential between the craft would just lead to a big explosion when they met.

Again,

1) If they have any velocity difference they do not have matching orbits

2) I been able to "dock" ships traveling at up to 25 m/s from each other

If you reckon you can do it without matching orbits, take a screenshot just before the craft dock, showing relative velocity, followed by a second immediate screenshot of the map view, showing the orbits of the two craft.

I've thought I have done that already?

But I am testing a KASless "butting" system now so here are the freshly printed screenshots:

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It appears his plan is to anchor to the other craft with KAS, which really isn't docking. THe OP should thus be updated citing that KAS is a legal form of "docking".

No, you can use KAS or what ever to grab on to each other, once your have neutralized their relative velocity by some other means than thrusters, then you need to bring them in somehow to dock.

Edited October 1, 2013 by RuBisCO

[RuBisCO]

Its been several versions since then, certianly the robotic parts have change with IRP 19, I'm going to test this again see how fast I can get crafts to slam into each other and not break. Any takers?

[Tsevion]

Its been several versions since then, certianly the robotic parts have change with IRP 19, I'm going to test this again see how fast I can get crafts to slam into each other and not break. Any takers?

You know, this challenge is stupid enough I just might try it. Just double checking two things, otherwise doing this stock is just an exercise in frustration:

1) Does the claw count as a docking port? Seeing as it docks the ships...

2) Can I use an asteroid as part of one of my craft?

[RuBisCO]

Well when this challange was made there was no claw or asteroids, so sure why not. I love to know at what speed the claw can get up to before breaking, I would think the kind of contraptions like KAS or the robotic "anters" can handle greater speeds because much of the kinetic energy remains as spinning of both craft after harpooning or butting each other.

[Tsevion]

Yeah... mostly the asteroids themselves are near indestructible... and then I'll just try applying lithobraking techniques to slow down enough for the claw to work... should be interesting.

[GoSlash27]

This is a matter of docking 2 ships at different energy levels; like sinking a 3 pointer from the other side of the planet.

The ship at the higher circular orbit has more velocity than the intercepting ship on the Hohmann transfer from lower orbit.

How is one supposed to match speed with all of the standard methods disallowed? I dunno, but it'll be interesting to find out.

Best,

-Slashy

[RuBisCO]

Yeah... mostly the asteroids themselves are near indestructible... and then I'll just try applying lithobraking techniques to slow down enough for the claw to work... should be interesting.

Interesting, but I think you will be limited by clipping: I have ships with "antlers" (seen in images above) that simply fly through each other because they were moving too fast for the physic engine to recognize that they that made contact. You need to turn up the physics calculating speed to max.

I'm trying this now again in .25, think I tried this last year in .20.

[Tsevion]

Well, using the ramming an asteroid technique I can get from 150 m/s relative velocity to 5 to 25 m/s relative velocity... but I haven't quite gotten it to latch on yet... and it's a bit unpredictable. I do have 15 minutes of hilarious video of a ship repeatedly ramming into and bouncing off an asteroid with various pieces destroyed... so there's that.

Gonna keep at it tomorrow night, and redesign the ramming ship a bit.