TransX S. major diff.

[Mister Mxyzptlk]

What exactly does the "S. Major diff. " readout in transX mean? I know that it relates to the "inward" "outward" component of the adjustment parameters and that if the overlay of the actual burn elipse and the hypothetical burn elipse is not congruent, I can tweak my burn by applying deltaV inward or outward and fine tune my burn to coincide with the hypothetical burn. I know as I do this properly, S. major diff. decreases to a very small value.

So I have 2 questions: What is the unabbreviated term, and if I fine tune S. major diff., deltaV, and relative inclination in the stage 1 transX screen, Is my burn as accurate as it would be if I used maneuver mode? This is probably a question for flytandem, tofitouf, or duncans.

 

[agentgonzo]

It's the angle (in degrees) between the (semi) major axis of the vessel's current (or possibly target) orbit and the (semi) major axis of the planet/moon's orbit.
Short for semi-major [axis] difference

I think the burn will always be more accurate in manoeuvre mode when compared with eject. Personally, I've never used it and those lines of code were from duncans's original code before I took over.

 

[Mister Mxyzptlk]

Thank you. I should have included you in the list of who would be able to answer the question.

 

[Wishbone]

Channelling Mr.GrowingRage, why would you post a new thread if you expect only a handful of people you deem intelligent enough to answer it? Why not PM them instead?

 

[agentgonzo]

Because if he'd have PM'd just a few people then others inthe community with the knowledge would not have seen the query and answered it as is what happens - duncans hasn't been active in the orbiter community for years. Not sure about tofitouf.

On the other side, the dissemination of knowledge is always good. Other people can read the answer and themselves be enlightened by its warming glow on an open forum that they wouldn't be able to do if it was just via a handful of ppl on PM.

 

[Mister Mxyzptlk]

Thanks agentgonzo, you took the words right out of my mouth.

The reason I started this thread is that I am an avid transX proponent and I have been doing some testing.

I set up a DG scenario whereby I eject from Earth to Mars by two methods. One is the maneuver method and the other is the eject plan method where I use the S. major diff., and the deltaV readings to fine tune my eject burn.

I wanted to test the accuracy of using S.major Diff. versus maneuver mode.