Talk:Tutorial:How to get to Duna

Launch to Kerbin Orbit

I'm a little confused by the following in step 3, launching into Kerbin orbit:

…heading east instead of the usual west.

The normal ascent to orbit from KSC is going east, taking advantage of the small amount of rotational velocity you start out with from Kerbin's own rotation, into a counter-clockwise orbit (this is also mentioned just after the above quote). So, either step 3 is incorrect in some way, or it needs more explanation to clarify the intention.

I'm not claiming expertise here, but I'm struggling to see why you'd do anything other than a standard east / 090° ascent from KSC, at least as your initial launch to orbit when keeping it simple. An advanced departure might try to do something like matching the solar orbital plane, I guess, but that's easy enough to do either as part of the later Hohmann transfer, or fine tuning the intercept once in solar orbit. Matching Duna's plane wouldn't account for an opposite launch.

So, should this just be a standard launch to orbit heading 090°, or what am I failing to see here?

--Murph (talk) 02:30, 23 November 2013 (CST)

I had the exact same question and came to discussion to see if there was a discussion/explanation. I'm going to edit it; if we're missing something, please do add a clarification while reverting.

Kenberto (talk) 02:05, 14 January 2014 (CST)

Edit: Very helpful instructions. Just wanted to say that the numbers described are accurate only if your orbits and alignments match up, which isn't exactly possible without a way to measure the angles and accurately drag the maneuver nodes into intended positions. I think the angles/clock references mean the sun as the center and the planet of origin as the 3 o'clock position for alignment of planets, and the planet of origin as the center and the sun as the 9 o'clock position for when to make the burn. When using maneuver nodes, I had to drag them back and forth in the general area to find a good balance of delta v and time to intercept. I've also found that making course adjustments as soon as possible to get the desired periapsis saves the most fuel. The maneuver node seems buggy and wont appear for me until the ship has escaped the planet of origin. I adjust all 3 axes to try to get the best periapsis. Sometimes I have to make a 2nd adjustment because the first one's periapsis changed by itself midway into the transfer. The RCS was helpful with making tiny adjustments, especially at the end of the burn. I also found that if my velocity into Duna was higher than ideal, I had to get my periapsis on Duna aerobaking to as low as 11km in order to produce an apoapsis. As the instructions stated, 10k and below seems to brake into a landing. Username is Hodor, October 15, 2014