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[PLUGIN 0.17] AdamKSP - Show Phase and Ejection Angle, DRAW trajectory on map - v0.6


adammada

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Is there any plan to calculate in the planet's eccentricity?

The eccentricity of the planets, especially Duna's, is not much but it is enough to make this data given by the calculator completely unreliable, in terms of getting a direct transfer with the lowest delta v possible, which is what I'm after. I've been getting a few hits and a lot of misses. It's a bit frustrating. Everywhere I've looked, every mod, even the interplanetary transfers guide thread and the online calculator that was created, no one has even bothered to calculate it, like it's too much of a headache or something. It's just one extra variable. I'm a bit rusty with my math but I'm about to go about it myself if no one else is.

That one extra variable throws a big wrench in calculating intercepts, and even if eccentricity were accounted for, then there's inclination relative to the sun. Eventhough it's simplified (thankfully) since KSP doesn't use n-body math, and a patched conics system instead, it's remarkably more difficult to go from calculating intercepts of two children of one parent body on a flat plane, where both have 0 inclination and 0 eccentricity, to calculating intercepts where those numbers change. People are working the problem, from various angles, but it's going to take time for anyone to get it done right, since it does involve complex math, and when you start doing complex math with computer code, things sometimes get wacky. (Floating point values are both a blessing, and a curse, sometimes. >.< )

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Very useful mode, but I noticed a problem when more than one vehicle with this mod are close to one another. The window gets stuck in the middle of the screen (wherever it was before), and is impossible to move for any of the vehicles or debris in the area.

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How exactly does the trajectory simulation work?

That is really simlpe. Every body (like planet or vessel) has assigned orbit, and orbit has function "getPositionAtUT( time )" . So i'm calculating 20 positions of vessel and planet in time, then connecting them with lines.

There is place for improvment like:

- positions of planet could be counted only once

- positions of vessel only when vessel accelerates

- draw lines not equally in time, but first find closest point and then draw lines around it

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I'm having a slight issue with this awesome plugin:

Sometimes the ejection angle I need never actually occurs...

Kinda hard to explain but let's say I need a 151 degree ejection angle for my Duna burn, but the highest value my ejection angle ever gets to is 6 degrees and then it falls all the way down into the negatives, reaches negative, say, 250, then starts back at positive 6 falling down. I'm not really sure what to do in these situations. Quicksaving, reloading doesn't work.

Is there some fundamental orbital principle I'm missing here or is this a bug?

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Any one got an idea on my issue posted above?

Sometimes the ejection angle starts counting down from as high as +500! I don't understand how I can be at a 500+ degree angle to Kerbin's direction of travel around Kerbol. Shouldn't the maximum be 360?

It's frustrating as I'm trying to work out the perfect launch/ejection parameters for my ship. I did one perfect ejection to Duna with a 44.49 phase angle, starting my departure burn at +137 on the ejection angle. Next session I loaded and I've fast forwarded a year to the next window, but at a 44.49 phase angle the ejection angle doesn't pass +137; instead it may start at +50 and drop down to -300. Why is this happening?

Annoyingly what this means is that for every launch window I have to trial and error my departure timings, using lots of quicksaves and loads. Surely on every orbit of Kerbin I pass +137 degrees? Why does this plugin sometimes miss it all together?

I'm sorry that this is so hard to explain..

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