mechjeb, ascent guidance inclination, and contracts.

[tg626]

I had a heck of a time today trying to Gert the right inclination for a satellite contract today. I can't recall the exact Longitude of Ascending Node, but I think it was 348° and the inclination was 160.1°.

Setting mj to 160° was wrong, turns out -160° was correct. Studying the impact of the Longitude of Asending Node reveals that mj seems to assume its 0°.

So I'm looking for confirmation of this, and guidance on how to translate inclination from a given Longitude of Ascending Node to mechjebs assumed LoAN.

Edited January 23, 2015 by tg626

[KerBlam]

I've heard that Mechjeb uses 180>-180, whereas KSP generally uses a 360 degree compass for inclination.

I'm not sure about orientation, or how this interprets, but if I had to guess, I would say that the negative figures are south.

Also, this is third hand, and I have no references or proof of correctness.. sooo pretty much disregard this post

[sarbian]

From the post I am not sure you grasp the definition of the Longitude of Ascending Node.

[tg626]

My grasp is tenuous. If fact further thought last night as I fell asleep lead me to realize 300some degrees can't be right as that's nearly all the way around to 0 again and it appeared that my fight was a mirror of what it was supposed to be.

[tg626]

Ok, got it. The reason that 160 degrees was the wrong setting was because I was launching when the DESCENDING node was directly above KSC. Had I been launching when the ASCENDING node of my target orbit was above KSC, then 160 degrees would have been the correct setting.

Since I was launching when the DESCENDING node was above KSC, I needed to set MechJebs "Inclination" to -160 degrees.

(duh)

BTW, the stated orbital parameters were:

[TABLE=width: 500]

[TR]

[TD]Apoapsis:[/TD]

[TD]5,338,346 [/TD]

[TD]meters[/TD]

[/TR]

[TR]

[TD]Periapsis:[/TD]

[TD]4,825,057 [/TD]

[TD]meters[/TD]

[/TR]

[TR]

[TD]Inclination:[/TD]

[TD]160.1 [/TD]

[TD]degrees[/TD]

[/TR]

[TR]

[TD]Longitude of Ascending Node:[/TD]

[TD]346.3 [/TD]

[TD]degrees[/TD]

[/TR]

[TR]

[TD]Argument of Periapsis:[/TD]

[TD]undefined[/TD]

[TD][/TD]

[/TR]

[/TABLE]

Edited January 24, 2015 by tg626