Transfer

[PhatZilla]

I have a question regarding transferring to another planet. My method thus far has been as follows...I'll use Duna as an example.

First, I get into a circular orbit around kerbin, usually 80k. Once in orbit, I burn prograde until I escape the Kerbol system and enter a solar orbit. From a solar orbit, I'll make a node and play with it until I get an encounter, but I usually get the encounter on the opposite side of my orbit. My question is, is it better to extend my orbit and get an encounter far far away from my current position, or to wait until I am just behind the planet...I'm having trouble explaining, so I'll include some poorly drawn MS Paint examples. The first is how I currently do it.

I raise the other side of my orbit until it matches that of Duna

Is this a better method?

[stupid_chris]

What you want to do is wait for the right phasing angle. Each planet has different phasing angles from Kerbin. There are different tools to calculate phasing angles, but the simplest one is MechJeb or Protractor. Basically, you want to set your maneuver node and do your transfer burn when the angle equals to zero. But for your question, the first image you posted is far far more efficient.

Images to help you understand phase angles:

Edited July 22, 2013 by stupid_chris

[Pursuedtank]

Follow all of that, but make sure you do the whole burn at 80km don't burn until you escape and then burn to get an encounter. It will be far more efficient at the 80km orbit due to the oberth effect.

[PhatZilla]

Thank you so much. That makes sense. Definitely appreciate the detailed answer.

[dave4002000]

Another trick to lining up phase angles is to use the protractor mod and do your timewarp while you are still sitting on the launchpad. That way you can take advantage of high-warp speeds. I'll timewarp on the pad until Protractor says the ideal angle is about 30mins away. Then i'll launch, circularize and eject without having to timewarp once in orbit.

I also find it amusing that that dV map shows 40,000m/s needed to depart from Jool's "surface"...haha.

[draeath]

Enjoy.

This is not a mod, it's an external calculation tool. It's up to you to put the data in (or read from your persistent state file) and then up to you to execute the maneuvers it suggests.

Yes.... this can help you plan Voyager-style gravity-assists!

Edited July 23, 2013 by draeath