Orbit direction

[MrAnonymous]

How do you determine the direction of your orbit around a planet ie: prograde, retrograde orbit? Is it based on the rotation of a planet or the planet's direction of orbit around the sun? I was watching Scott Manley and he said something about this during his Eve mission and I was just wondering.

[Jimbimbibble]

All bodies in KSP rotate counter-clockwise, so a prograde orbit is always East and retrograde is West.

[FREEFALL1984]

You only want to orbit in the direction of the planet because its ever so slightly more efficient, since you gain surface rotation speeds at ground level on top of your orbital speeds. On a tidally locked body with no atmosphere it makes no (or ridiculously little) difference which way you go. When introducing interplanetary orbits the gain/loss by orbiting kerbin in the correct/wrong direction makes so little difference that it doesn't really matter.

But one very important thing to consider, if you plan on docking two craft together, make sure they're both orbiting the same way otherwise it can be a pain getting them to, Yknow, not explode into a million pieces at 4500m/s

[Starstrider42]

How do you determine the direction of your orbit around a planet ie: prograde, retrograde orbit? Is it based on the rotation of a planet or the planet's direction of orbit around the sun? I was watching Scott Manley and he said something about this during his Eve mission and I was just wondering.

Technically, prograde/retrograde is always defined relative to the rotation of the planet. However, since all planets in KSP have zero axial tilt, the distinction doesn't actually come up.

[cantab]

Yeah, prograde is the same way the planet spins. If you're not sure, quicksave then timewarp and it'll be obvious.