Hover at Lagrange points ?

[Volff]

Is there a possibility to hover at a Lagrange point (ie. a point where a relative rest between two massive bodies can be achieved - there should be 5 such points) ?

It looks from the behaviour of the orbiting spacecraft that the Mun gravity has a restricted range (2.5 M meters or something ...), and when the Mun gravity turns on, Kerbin gravity is off. Am I right ?

[Sordid]

That\'s exactly how it is. KSP uses patched conic approximation where the spacecraft is only ever affected by one body at a time. One of the shortcomings of this method is that it doesn\'t simulate Lagrange points.

[Hypocee]

Except that it also doesn\'t simulate any real-world chaotic perturbations, so the two points that are fully stable are (as) stable (as every other orbit) in KSP too.

1. Go to L4 or L5.

2. Stay there forever.

3. Profit.

[OtherDalfite]

Except that it also doesn\'t simulate any real-world chaotic perturbations, so the two points that are fully stable are (as) stable (as every other orbit) in KSP too.

1. Go to L4 or L5.

2. Stay there forever.

3. Profit.

You for the ??? step.

[Volff]

As the Mun gravity does not work at a distance, the L4 and L5 cover most of the Mun orbit - you just enter it, and as long as you are out of Mun reach, you should stay immobile in relation to the Mun and Kerbin.

[Cepheus]

I have found that, when outside of Kerbin or the Mun\'s SOI, you can burn your velocity to 0.0 m/s, and you\'ll stay where you are. Set time compression to 10000x, and make sure that you don\'t accelerate toward the sun. In most cases, you won\'t.

[WX_Echo]

I have found that, when outside of Kerbin or the Mun\'s SOI, you can burn your velocity to 0.0 m/s, and you\'ll stay where you are. Set time compression to 10000x, and make sure that you don\'t accelerate toward the sun. In most cases, you won\'t.

It just occurred to me that this technique, although relatively clever, breaks the spirit of the original problem Lagrange, Euler, et al. were trying to solve. Specifically, burning to zero heliocentric velocity in this sense means you have no orbital period. Since Lagrange points are, in effect, locations where the rotating reference frame of a spacecraft or satellite will orbit with the same period as the much larger co-orbiting bodies (e.g. Earth-Sun), you have found a unique way of simulating this with KSP physics. Well done!

Also, L4 and L5 will only be stable (in a real system) if the mass ratio of the co-orbiting bodies is sufficiently large. Thankfully for us, Kerbin-Mun L4/5 and Kerbol-Kerbin L4/5 satisfy this requirement.

http://en.wikipedia.org/wiki/Lagrangian_point

The responses so far have covered the important points, but I thought it would be useful to provide the reference SOI data:

Kerbin - SOI: 84275 km (140 body radii)

Mun - SOI: 2430 km (12 body radii)