Duna Encounter?

[GalaxiesFinestToday]

Can anyone tell me how to get a duna encounter, ive been trying and trying but i just can't get one. (ive been using maneuvers and still i don't get one)

[astropapi1]

http://ksp.olex.biz/

The default page has the calculations for a Duna transfer.

[GalaxiesFinestToday]

Hmm seems confusing

[Pursuedtank]

It's all about the phase angles, you can use this website to work it out, or you can use a mod like protractor to help you get the right time to burn.

[Boex]

Sorry, but if a couple of drop-down bars and an orbital map confuses you, you should probably try getting so more practice with Mun and Minmus transfers.

[Anglave]

Step 1) Get your ship into Low Kerbin Orbit. This should be an equatorial prograde orbit. From the pad, you want to turn along the 90° line (the "D" direction) only.

Step 2) Get your departure timing (called 'phase angle') right. Check here. You'll find that you should leave Kerbin when Duna is roughly 45° ahead of Kerbin in their paths around the sun.

Step 3) Get your ejection timing (called 'ejection angle') right. Zoom out so you can see Kerbin's orbit. Find the direction of Kerbin's travel around the sun. That's the direction you want to leave Kerbin orbit in. Place a manuver node about 180° opposite that direction on your ship's orbit around Kerbin, and pull the prograde handle until your projected trajectory escapes Kerbin.

This is what the second picture on that web page is showing you, that you want your manuver node to be where the "ship" icon is in the picture, more or less.

Step 4) It's more efficient to make corrections earlier in your path than later. You should probably be able to get a Duna encounter from your Kerbin Ejection maneuver node, but if you can't that's ok. Time your burns right and make your orbit around the sun get as close to Duna's as you can. You should only need to adjust them prograde/retrograde at this point.

Step 5) After you have a trajectory that takes you very close to Duna's orbit, set Duna as a target and the game will show you where the plane of your orbit crosses the plane of Duna's orbit with a little green tag. Put a maneuver node there and adjust your orbit normal/antinormal (the pink handles) until that little green tag reads 0.0. This will align your orbital plane with Duna's.

Step 6) Now you should be approaching Duna's orbital distance from the sun, in the same plane as her orbit, and your trajectory should touch her orbit just about when she'll be there. If you don't have an encounter yet, make a new maneuver and adjust your orbit in or out, up or down (blue and green handles) until you find one.

Step 6 and Step 5 can happen interchangeably, it's better to do large corrections earlier, but it's more efficient to do your plane correction at the crossing node.

Edited May 30, 2013 by Anglave

[GalaxiesFinestToday]

Oh ok I see