Kerbal physics versus N-body physics

[krakken232]

Having slightly more than a basic knowledge of gravitational principles and n-body physics (n-body simulators being a hallmark of Computer Science programs at the university I attended) I knew there are huge differences between single-body physics universes and n-body ones.

I know N-body physics might never be implemented in KSP, which is fine, but I thought it would be interesting to get some perspectives on what the implications of N-body physics on the Kerbal universe might be. What possibilities would this open up for Kerbonauts? What, for instance, would be different about lining up a Mun shot, transferring orbits, or even orbiting Kerbin itself?

[Kosmo-not]

Lagrangian points for one.

[ferram4]

All the orbits around Kerbin and the Mun would be disrupted by the other body and Kerbol.

[krakken232]

All the orbits around Kerbin and the Mun would be disrupted by the other body and Kerbol.

So how would you account for this or offset it using the game\'s ship controls? Would it be possible to maintain a nice, low, circular orbit of the Mun?

[Cykyrios]

It all depends on what 'low orbit' means in regard to altitude, but as long as you stay below a given altitude, the influence of Kerbin would be so minimal that it would be negligible. The farther you\'d get from the Mun, the more Kerbin\'s gravity would attract you, until a Lagrange point (if you\'re right between Kerbin and the Mun, that is, aligned with them), and then Kerbin would catch you, and the Mun would still attract you, until you get low enough around Kerbin, etc.

Someone posted a chart somewhere on the forum displaying the trajectory of a ship in 2- and 3-body physics, and the difference was rather small.

TL;DR: N-body physics aren\'t worth the trouble, performance-wise and accuracy-wise

[Alchemist]

N-body solution gives somethig very different in 3 cases:

1) On SOI border (but despite notably different acceleration it really affects you only if you try to stay there, it doesn\'t affect SOI transitions much)

2) synchronized orbits - but it will take multiple orbit periods to feel the effect

3) very long time

direct effects of the border zone would be interesting, but the other features could cause more numerical imprecisions than the real efect.