Does your launch latitude affect your speed at launch (in KSP)?

[smjjames]

I know it does in the real world because you get a bigger boost from the planets rotation at the equator than you would at the poles. However, I'm just wondering if it's also true for KSP? Like does KSP simulate that?

Edited April 6, 2015 by smjjames

[HoloYolo]

Yes, but barely.

[Eric S]

As Kaboom says, yes. basically, like the Oberth Effect, it doesn't need to be programmed into the simulation, it's just present from the level of physics simulation that's already present.

[smjjames]

Oh, it's there, just barely has an effect due to the scale?

[Deutherius]

I wouldn't call 200 m/s "barely", but yes, a larger planet with the same rotational velocity would give you a bigger kick at the equator.

[Taki117]

I wouldn't call 200 m/s "barely", but yes, a larger planet with the same rotational velocity would give you a bigger kick at the equator.

But the difference in orbital speed from the Equator to the poles is far less than that. While there is a difference, it is only maybe a few m/s, not enough to worry about in the grans scheme of things.

[Deutherius]

But the difference in orbital speed from the Equator to the poles is far less than that. While there is a difference, it is only maybe a few m/s, not enough to worry about in the grans scheme of things.

Unless I'm misinterpreting the question, I think the OP was not concerned by orbital velocity in orbit, but on the ground. Standing at the pole, the planet is not moving you anywhere, it's just rotating you. Standing at the equator, the planet is dragging you with the surface at about 200 m/s - quite a difference, I would say.

[Eric S]

174.53 m/s to be precise, according to the wiki, so more than a few m/s, but not so much that it drastically alters launch vehicles.

[Leszek]

At the equator it is something like 172 m/s rounded to 200 above. You can check by changing the navball to orbital while on the launch pad.

At 45 north latitude it drops to 70% of that number. (Basic trig math. Same is true for Baikonur which is also at 45 north.)

For comparison on Earth and Kerban (Assuming 172 m/s which is going by memory.) the numbers are:

Earth -- Kerban

Equator: 464 m/s. -- 172 m/s

Kennedy Space Center (28 North): 410 m/s -- 152 m/s

Baikonur (45 North): 328 m/s -- 122 m/s

60 North: 232 m/s -- 86 m/s

Since Kerban is a ball and it is spinning the simulator takes this effect into consideration automatically, no special coding of the physics is necessary. Taking off retrograde requires double these numbers in extra DV.

P.S. I see from the post above the value is 174 m/s. I don't want to do the math again, the change is small enough really.

Edited April 6, 2015 by Leszek
P.S.

[smjjames]

What about Minmus though? Or is the gravity so low there that it doesn't actually matter as much as it would on Kerbin?

[Taki117]

What about Minmus though? Or is the gravity so low there that it doesn't actually matter as much as it would on Kerbin?

With both the Mun and Minmus the Gravity is so low, and their rotation so slow that it has no effect.

[smjjames]

With both the Mun and Minmus the Gravity is so low, and their rotation so slow that it has no effect.

Okay cool, that's pretty much what I was wondering, though I could have articulated that.

[Leszek]

One of them, I think Minmus has an equatorial boost of 10 m/s. So that would be 7 m/s at 45 north and 5 m/s at 60 north. So for all intents and purposes nothing. If your Delta V budget is that tight that it matters, I would argue you have under built your rocket. The Mun I think is less, it takes 6 days to complete a rotation, but I didn't do the math or look it up. It is not going to be much though.

When landed on a planet or moon, just switch the navball to orbital mod and it will say what the boost is where you are.

[smjjames]

When landed on a planet or moon, just switch the navball to orbital mod and it will say what the boost is where you are.

Oh, I didn't know that's what it showed, cool.

[FleshJeb]

What you're talking about is listed as the Sidereal Rotational Velocity, and it's in the sidebar: http://wiki.kerbalspaceprogram.com/wiki/Kerbin

This varies with the cosine of the latitude.

Kerbin has the highest SRV of all the bodies you can land on. For all the rest, it's not really worth accounting for (except maybe Eeloo).