Launch Azimuth

[eevenson]

What is the best way to fly on a specific launch azimuth? If I want to reach an orbit with 0 or 180 degrees inclination this is easy -- I just yaw over on the launch pad. But if I want to reach a 90 degree inclination (straight north) this is more difficult because of Kerbal's rotation. I guess I have to just lean into it a bit eh?

[AmpsterMan]

I have no Idea what you are asking, but I can provide what (I think ) is some insight.

Since Kerbin is situated 0 Degrees to the Ecliptic, and it has not inclination to it's Orbit, to launch with a certain in inclination all you have to do is subtract that inclination from 90 and it will give you which heading you have to go for.

Example, if you wanted to launch with an inclination of 7.5 degrees (to get to Minmus without a plane change for example) You have to launch at 90-7.5= 82.5 heading. If you want to be in a Polar Orbit going north, then you do 90-90= 0 Aim to zero. If you want Polar going south you subtract 270-90= 180 etc.

Don't know if this is official or not but it works.

[Kimberly]

AmpsterMan has it right. If you want to get into a polar orbit, just launch north (or south). Keep your heading trained on the northward orange line on the Navball, and you will tend to have a polar orbit. You can make minor corrections in orbit if necessary.

[stupid_chris]

I think what OP meant is how Kerbin's will affect your orbit. And he's right, launching straight on a north vector is going to leave you on an orbit with an inclination of about 85deg, not 90deg, because you already have home sideways velocity when launching. So if you want to launch on a perfectly polar orbit, you'll have to kill this velocity at one point or another. You can do it directly while launching, I don't know the math exactly, but by launching just a bit west of the north vector, you'll be closer to a polar orbit. Else I know MechJeb takes in account for Kerbin's rotation while launching. Else, I can tell you that modifying your orbit once up there is probably the easiest way to do. You won't be far form a near polar orbit, and the maneuver to get polar won't need much delta V. It's up to you to chose how you wanna do it.

[K^2]

Switch your navball to show orbital velocity instead of surface velocity. At about 8-10 km, when you begin your rotation, just get your prograde marker to point straight north. For a polar orbit, that will get you a perfect orbit regardless of anything else. If you want some other inclination, you might have to make some further adjustments, depending on how far your position has shifted, but you should still be able to get very close.

[el_coyoto]

For launches to inclinations other than polar, I remember implementing this on my TI-85 during my Orbiter days :

http://www.orbiterwiki.org/wiki/Launch_Azimuth

But the navball trick is cool for getting into a precise polar orbit without maths!

[purpletarget]

You can also figure it out with half a minute of trig and a calculator, or 10 seconds with a relvel board, compass and rolling ruler, or ruler and triangle.

http://forum.kerbalspaceprogram.com/showthread.php/24623-Tutorial-Video-Krash-Test-Kerbals-How-to-science%21?p=387855&viewfull=1#post387855