How to read the nav ball? specifically, on the Mun or other planets

[TexRob]

I have no problem getting to the Mun, landing, and having a ton of fuel for my return, BUT I really struggle with leaving. I don't know how to take off to put myself in a relatively planar orbit with Mun's orbit around Kerbin. Any tips?

Edited December 31, 2013 by TexRob

[Superfluous J]

You do it the same way you'd take off from KSC, assumign you're near the equator of the Mun. I suggest landing near the equator until you're more comfortable with the nav ball.

One thing, North won't be "down" on the navball unless you got lucky on your landing (or aimed it that way). So you won't want to just go to the right for your gravity turn. You'll want to go 90 degrees counter clockwise from the red line on the navball. So if North is pointing to the right, you want to go "up" on the navball.

Also, do your gravity turn pretty much immediately. Unless you're going to crash into a mountain or crater wall, there is NO benefit from waiting until you're a certain height. Just lift, and immediately turn to the side and go.

[federicoaa]

I guess you mean equatorial orbit around moon. You can only doing at launch if you launch from the equator. What you can do is once you take off point to the 90 degree mark (if you put the N line pointing downwards, it is at the right.

[vexx32]

You don't really need a planar orbit. All you need to do is attain orbit, and then escape the Mun's SOI. As long as you don't escape by too​ much, you can just burn retrograde once you're in Kerbin orbit again.

[TexRob]

You don't really need a planar orbit. All you need to do is attain orbit, and then escape the Mun's SOI. As long as you don't escape by too​ much, you can just burn retrograde once you're in Kerbin orbit again.

Yeah, I am feeling kind of dumb. Reminds me of Apollo 13, "I can just look out the window". I just did it by aiming straight for Kerbin almost immediately after lift off, and then get into an orbit on a plane that is pointing towards Kerbin. Then I can just burn on the backside of the Mun to exit towards Kerbin. It was easy for the most part. I was worrying about getting in a planar orbit too much.

[Smidge204]

Assuming you want to go directly home from Mun, you want to leave retrograte to Mun's orbit. This will result in you having a velocity that's lower than Mun's (relative to Kerbin) and therefore a lower Pe, getting you closer to home.

Remember that Mun orbits in a counter-clockwise motion, viewed from "above."

So orient the camera looking "down" on Mun, with Kebin above so Mun's orbital line in map view makes an upward curve like a smile. From this view, you want to go to the left.

If you're on the Kerbin-facing side of Mun, that means going East.

If you're on the "dark" side with Kerbin below the horizon, go West.

The easiest place to return to Kerbin from Mun is a landing at 0 degrees Lattitude and 140 degrees Longitude. This is almost exactly on Mun's trailing side and you just go straight up.

When in doubt, get yourself into a low orbit (8000m is good - high enough to clear the tallest peaks) and use maneuver nodes. Remember you want to go clockwise as seen from above.

--------------

More generally to help with the Navball... imagine you are inside a giant translucent sphere. You can see the surrounding sky and landscape through the sphere.

Imagine a line drawn on the inside of this sphere along the true horizon. That is the line between blue and orange sides of the navball. Orange is part of the sphere below the ground, blue is the part above the ground.

Imagine a line drain from the due north direction to the point directly above your head. That is the red "North" line.

The rest of the lines are just marking angles indicating which direction you're facing : North/South/East/West lines run from the dot on the blue side to the dot on the orange side. The lines parallel to the horizon line indicate how "upward" or "downward" you are facing.

Now, because you're not actually inside a giant sphere but looking at a tiny navball instrument, you have to turn that sphere inside out. That's why East is counter-clockwise from North on the navball, where it's normally clockwise on a compass.

=Smidge=

[TexRob]

Assuming you want to go directly home from Mun, you want to leave retrograte to Mun's orbit. This will result in you having a velocity that's lower than Mun's (relative to Kerbin) and therefore a lower Pe, getting you closer to home.

Remember that Mun orbits in a counter-clockwise motion, viewed from "above."

http://www.smidgeindustriesltd.com/ksp/navhelp01.jpg

So orient the camera looking "down" on Mun, with Kebin above so Mun's orbital line in map view makes an upward curve like a smile. From this view, you want to go to the left.

If you're on the Kerbin-facing side of Mun, that means going East.

If you're on the "dark" side with Kerbin below the horizon, go West.

The easiest place to return to Kerbin from Mun is a landing at 0 degrees Lattitude and 140 degrees Longitude. This is almost exactly on Mun's trailing side and you just go straight up.

When in doubt, get yourself into a low orbit (8000m is good - high enough to clear the tallest peaks) and use maneuver nodes. Remember you want to go clockwise as seen from above.

--------------

More generally to help with the Navball... imagine you are inside a giant translucent sphere. You can see the surrounding sky and landscape through the sphere.

Imagine a line drawn on the inside of this sphere along the true horizon. That is the line between blue and orange sides of the navball. Orange is part of the sphere below the ground, blue is the part above the ground.

Imagine a line drain from the due north direction to the point directly above your head. That is the red "North" line.

The rest of the lines are just marking angles indicating which direction you're facing : North/South/East/West lines run from the dot on the blue side to the dot on the orange side. The lines parallel to the horizon line indicate how "upward" or "downward" you are facing.

Now, because you're not actually inside a giant sphere but looking at a tiny navball instrument, you have to turn that sphere inside out. That's why East is counter-clockwise from North on the navball, where it's normally clockwise on a compass.

=Smidge=

Thanks, this is a helpful post. I understand how the nav ball works, but that's still a great explanation. I was just not sure how to know what is what on the Mun, but you outlined that above, useful info to have.