Does KSP model conservation of angular momentum?

[Goody1981]

Topical as the Juno probe is a week and a half away from insertion into Joo  Jupiter orbit... Does KSP model angular momentum?

I've seen that the Juno probe is spin-stabilised - and when it left the booster it was spinning at a certain speed, which reduced substantially as the large solar panels were unfolded.  Would this be replicable in-game? I can't remember any instance of extending solar panels affecting anything, but I doubt I have ever done it while spinning (not in a position to check in the game for the next day or so)

[Guest]

All rotation is stopped when you enter timewarp so ... yes, but only if you play in real time.

[Jovus]

There's a mod called Persistent Rotation.

 

But even with that, I think not. I've never seen changes in angular momentum due to changes in craft mass distributions that don't involve adding or losing parts. This itself is excusable; I don't think the game tracks the mass distribution of an open solar panel vs. a closed one. However, I think the game is just using a moment of inertia scalar instead of tensor, because I've never seen an unstable axis of rotation.

[Goody1981]

14 minutes ago, regex said:

All rotation is stopped when you enter timewarp so ... yes, but only if you play in real time.

Yeah I knew that things don't just keep spinning when you enter time warp, sorry for not clarifying, was more meaning exactly what @Jovus was talking about. Thanks to both of you

[SchweinAero]

3 hours ago, Jovus said:

However, I think the game is just using a moment of inertia scalar instead of tensor, because I've never seen an unstable axis of rotation.

Then it's about time you saw one.

Truth be told, this doesn't happen for single parts though.

[pincushionman]

Exrending the solar panels to slow rotation would mot work because the game doesn't move any masses around during the animations, and thus the moments of inertia don't change. You could accomplish it by pumping fuel from a center tank to saddle tanks on the side, though.

you could kludge it with some mod setups, though. Infernal Robotics moves parts around. Some KAS parts can do it, too; Scott Manley posted a video some time ago using a tether for a rotating-centrifugal-"gravity" setup. It was terrifying.

[Snark]

I don't think the game models the inertial effects of resource-pumping. When you pump fuel from one tank to another, it just magically teleports the mass from tank A to tank B, without exerting any force on the rest of the ship. So I don't think you can demonstrate the spin-faster-when-you-pull-your-arms-in effect by pumping fuel.

And of course, there are KSP's reaction wheels, which flagrantly violate conservation of angular momentum by magically creating torque out of nothing.

But in general, in terms of massy objects behaving correctly as they spin, bump each other, etc.: yes, KSP models conservation of angular momentum. It's a natural consequence of the physics built into the game engine.

[Jovus]

4 hours ago, SchweinAero said:

Then it's about time you saw one.

Cool! Thanks, this makes me really happy.

 

I guess I'm just not imaginative with my rocket designs.