Tidal locking satellites

[Las-pen]

How do you get a satellite or a space station to be tidal locked in their orbit. Is it even possible now? If not, are there any mods that would do the job?

[Skyrunner27]

Since once you get out of the 2.5km physics sphere the vehicle disappears for our purposes. No.

[Tex_NL]

In KSP this is currently not possible. And probably never will be. All craft outside physics range are completely ignored.

If you would extend the physics range far enough rotation and collisions would be calculated. However this would simultaneously increase the workload on the game engine slowing your game down from frames per second to seconds per frame.

[Claw]

Well, the 2.5km bubble isn't necessarily what prevents things from being tidally locked. KSP also does not simulate things like gravity gradients or magnetic alignment. So even within 2.5km, satellites and other objects will not stay tidally locked. I also doubt they will implement something like this since doesn't seem to fit in with the rest of the physics theme, but maybe some day.

Cheers,

~Claw

[worir4]

IRL if you spin your ship (roll) then it will stay in the same orientation in relation to the planet or moon you are orbiting (Thanks orbiter 2010) , But i think you can't do this with KSP. Maybe a mod that uses the same sort of thing that solar panels use to track the sun.

[KerikBalm]

"KSP also does not simulate things like gravity gradients"

Well, for 1 ship, no, but it certainly simulates a gravity gradient.

The problem is it only applies a force to the center of mass, not to each part individually.

As soon as you dock 2 ships... they become 1 with 1 center of mass.

I suspect, much like stock "hinges", that if you manage to "hook" some girders around another ship, such that they physically interact, then you could get a gravity gradient effect, but it would be pretty weak even if your girder "linkage" is nearly 2.5 km long - and as soon as you non-physics time warp, they'll just pass through each other and that would be the end of it...

[AlexanderB]

You can get Mechjeb to do it, but only as long as the ship is focussed, and no timewarp is used.

It'll re-align when you come back out of timewarp, but if you're the wrong way around with a big station, that might take a while for it to turn around.

[S1gmoid]

In KSP this is currently not possible. And probably never will be. All craft outside physics range are completely ignored.

Ignored by the stock physics simulation. They are still represented, with their movement modeled through a simplistic orbital model ("on rails"), and can be accessed. There are mods out there that mess with on-rails objects. But that isn't even necessary I think. We'd only need to set the correct orientation upon load (ie. start of simulation).

The real hard part is modifying the physics engine to actually keep the station tidally locked. Actually, there is already an ongoing attempt at doing n-body physics through replacing the stock gravitational model...

[Red Iron Crown]

The problem is it only applies a force to the center of mass, not to each part individually.

I don't think that's quite correct, gravity is definitely applied to individual parts of the same ship inside the physics bubble (you can see it when you have structurally unsound things sitting on the pad). I believe what prevents tidal locking is that gravity is calculated at the root part's altitude and then applied to each part individually, so there is no gravity gradient within a single ship.

[Claw]

I believe what prevents tidal locking is that gravity is calculated at the root part's altitude and then applied to each part individually, so there is no gravity gradient within a single ship.

Exactly, no gradient. Plus I'm not sure if the game has the precision for that.

And if you guys are talking about plugins, I think this one would be relatively easy to code up (if you just wanted simple tidal locking). Although I don't know how much demand there would be. Heck, you could even use the same module as a "star tracker" module for space based telescopes.

Cheers,

-Claw

Edited October 20, 2014 by Claw

[monstah]

Heck, you could even use the same module as a "star tracker" module for space based telescopes.

Wait, wad mod is that? Sounds interesting.

[metaphor]

I believe what prevents tidal locking is that gravity is calculated at the root part's altitude and then applied to each part individually, so there is no gravity gradient within a single ship.

Hmm, time to test that with tiny planets.

[Claw]

Wait, wad mod is that? Sounds interesting.

I don't know if there is one that does this already. I was saying that a mod that simulated tidal locking could also simulate being a star tracker in stable orbits. (At least the way I'm imaging it to be built.)

Maybe I'll look into this when I have time. If there's any interest.

Cheers,

-Claw

[Guest]

There are 2 mods that might help with this :

http://forum.kerbalspaceprogram.com/threads/67821-Timewarp-Rotation-Fix

http://forum.kerbalspaceprogram.com/threads/85990-0-23-5-Persistent-Momentum-1-0-%2814-July%29

It looks like neither one is up to date, but I bet it wouldn't be all that hard to continue the work these authors have started. As far as applying these mods to tidal locking, that might require quite a bit more coding to achieve the results you're looking for. Simulating the effects of gravity on a ship that's on rails might be difficult at best, but you could probably assign a particular part of the ship that always stays pointed towards the particular body you are in orbit around.

[Las-pen]

Those could work, if You could set the ship rotation juuusst right. Easier said than done

Edited October 23, 2014 by Las-pen

[Las-pen]

Maybe having ship to align itself on nodes.

Forgot can you actually do that.