Lagrangian Points

[The_Rocketeer]

Note for mods: This is a question about KSP's simulation limitations, albeit with an implicit mod suggestion. I'd prefer it wasn't treated as a mod suggestion in the first instance.

I understand that KSP's gravitational system doesn't allow for Lagrangian-like phenomena.

Is there any reason, though, why body-less SOIs in appropriately-scaled orbits can't be implemented to represent them? Has anybody though of making a mod for this?

I foresee one problem, being that lower/higher orbits than the associated 'parent' body would have shorter/longer orbital periods, so perhaps a permanent acceleration condition could be applied to them for station-keeping?

Or am I chasing someone else's tail - maybe this has been discussed before?

[Tex_NL]

... maybe this has been discussed before?

Only about a few dozen times.

As I understand it body-less SOI's cause nasty side effects. You're correct by saying ever lower orbits require ever higher orbital velocities. But as you approach zero altitude your velocity will approach infinity. Infinite velocity is an irresistible lure for the Kraken.

[Gargamel]

only about a few hundred times.

fyp tyvm

[The_Rocketeer]

Fair enough. I don't read every post around here, so I guess I'm not surprised.

On a related note, for a videogame KSP's limitations sometimes seem really random and arbitrary! Maybe I should give physics software engineers more credit.

[sal_vager]

I think what you are really looking for is Principia.

Faking a lagrange point with an empty SoI does not work, as instead of acting like a lagrange point it acts like a tiny black hole as the velocity needed to escape it increases the closer you get to the non-existent planet.

Also, lagrange points aren't spherical gravity wells, most are only nominally stable on certain axis and still require station keeping.

And yeah it's been brought up before

[The_Rocketeer]

I realise that an SOI is a poor representation of a real Lagrangian point, but then an SOI is a poor representation of any real gravity well.

[Red Iron Crown]

I realise that an SOI is a poor representation of a real Lagrangian point, but then an SOI is a poor representation of any real gravity well.

Not really, the patched conic/SoI model is a reasonable approximation of reality for many purposes, good enough to get us to the Moon and back.

An SoI is pretty much the opposite of a Lagrange point, an SoI is a well while a Lagrange point is a peak.

[The_Rocketeer]

An SoI is pretty much the opposite of a Lagrange point, an SoI is a well while a Lagrange point is a peak.

Well, that's only true if the force exerted by the SOI draws thing inwards rather than pushing them outwards.

With respect, I didn't ask the question knowing nothing about the physics of reality, I asked it not knowing why Lagrangian points are such a problem to implement in KSP, and why nobody had done what I was suggesting. For the purposes of a game like KSP, a sphere of influence could be just as reasonable an approximation of a Lagrangian point as it is for a planet's gravity well, even if the direction of gravity was wrong - lets face it, all the casual gamer wants a KSP Lagrangian point to do is let a craft stay there semi-indefinitely with minimal input.