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[1.12.x] Transfer Window Planner v1.8.0.0 (April 11)

TriggerAu

By TriggerAu
in KSP1 Mod Releases

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problemecium

problemecium

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Posted

I forgot to mention this before, but it'd also be pretty sweet if there were a button to turn the ejection parameters into a maneuver node (for ships that are already in orbit of course), and perhaps cooperate with KAC (if it happens to be installed) to create an alarm for the departure time.

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Superfluous J

Superfluous J

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Highly useful mod!

However, my node creating skills are limited. Can you please, please, please add the ability to turn the information generated into a maneuver node?

I have personally found that the only useful piece of information in those plots, after I've decided on which place on the plot I want to use, is the time.

Just fast forward to that time and then plop down a maneuver node about where you should eject, and pull it forward. When you get about to the orbit of your target planet (set it as a target!) you'll get encounter markers that should be really close to each other. Or you'll just get an encounter. Fiddle with the node, making little prograde/retrograde changes and dragging it back and forth a little in its orbit, and you should eventually nail a decent encounter. All you need is to be close, and then midway there (at the AN/DN is a nice time to do it) do a correction to get REAL close.

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Aedile

Aedile

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Posted
Highly useful mod!

However, my node creating skills are limited. Can you please, please, please add the ability to turn the information generated into a maneuver node?

Do you have precise node? You can use that.

However there is a catch. The point where the node needs to be is approximate. It's much more important to get the position right than the time. Just copying the time and adding the node there is pretty useless.

What I'd usually do is add a node with the correct burn, anywhere in the orbit, then move it back and forth and tweak it until the ejection angle/inclination somehow match. It is much easier the lower your orbital period is and the bigger the launch window is.

You can get pretty different results, sometimes it's worth it to start from higher orbit, and miss the perfect timing, sometimes it's not.

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Kolago

Kolago

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Posted (edited)

I don't get it.

I am like to go to Eve in RSS.

My Orbit is:

Apo 1.20005 Mm

Per 1.19947 Mm

Inc 28.326°

My Transfer is:

Kerbin (@1200km) -> Eve (@1200km)

Depart at: Year 1,Day 307, 00:00:00

UT: 26438400

Travel: 149 Days, 16:34:38

UT: 12933278

Arrive at: Year 2,Day 91, 16:34:38

UT: 39371678

Phase Angle: 36.32°

Ejection Angle: 322.78°

Ejection Inc.: -9.05°

Ejection Dv: 4821 m/s

Prograde Dv: 4445.7 m/s

Normal Dv: -1864.8 m/s

Heading: 112.76°

Insertion Inc.: -15.10°

Insertion Dv: 8641 m/s

Total Dv: 13462 m/s

What do I have to do to get this into Precise Node?

I have the Fields:

UT: -> This is Depart UT, thats clear.

Prograde: -> Here I put the Prograde Dv of 4445.7

Normal: -> Here I put the Normal Dv of -1864.8

Radial: -> 0 ????

Now Precise Node puts out:

Total Dv: 4820.97 -> good, thats pretty close to Ejection Dv

Ejection angel: 71.5° from retrograde -> thats far away from 322.78°

Eject. inclination: 2.87° south -> thats close but no cigar (-9.05°)

Apoapsis: -36647.37 km

Periapsis 1199.53 km

What do I have to do??? First change my orbit inclination to what? Ejection Inc.: -9.05°?

Edited by Kolago
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TriggerAu

TriggerAu

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Do you have precise node? You can use that.

However there is a catch. The point where the node needs to be is approximate. It's much more important to get the position right than the time. Just copying the time and adding the node there is pretty useless.

What I'd usually do is add a node with the correct burn, anywhere in the orbit, then move it back and forth and tweak it until the ejection angle/inclination somehow match. It is much easier the lower your orbital period is and the bigger the launch window is.

You can get pretty different results, sometimes it's worth it to start from higher orbit, and miss the perfect timing, sometimes it's not.

I do a similar thing - set my alarm for a couple of orbits before the "sweet spot", set a node for a little more than the ejection DV then move it around the orbit to the approximate ejection angle and then tweak it till it hits. Unless your vessel orbit is almost circular and equatorial all these tools do is give you best places to start (except for KSPTOT which does a lot of maths outside KSP to give you actual values)

A very nice mod, TriggerAu! It's gotten a nice speed boost since going in-game too, and incredibly convenient. :)

At this point, I have *all* of your mods installed. You make some very important, core tools. Thank you very much!

Kudos!

Glad you like it :)

I don't get it.

I am like to go to Eve in RSS.

My Orbit is:

Apo 1.20005 Mm

Per 1.19947 Mm

Inc 28.326°

.....

What do I have to do???

I think the issue here may be the Inclination of your initial orbit. The Lambert Solver in this and most KSP tools uses inclinations of 0 degrees, and you need to be close to that for the values to be exactly right. If I get the time and knowledge to get it to read the vessel orbit and give you exact values based on that then you could plug them in directly, but until then its unfortunately limited.

For the values your seeing - Radial would be Heading I'm pretty sure. The ejection angle of 322.78° is prograde, which would be 38° Retrograde (30 degrees diff to the 72 you have there - not "really" close on that one, but I think its the inclination thats throwing it off)

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Kolago

Kolago

Posted
Posted (edited)

Ok, changed my inclination to 0°. Fine tuned the UT to 26397671.423324 (was 26438400) and I have an encounter with an periapsis of 479.3 Mm.

Ejection angle: 14.97° from retrograde

Ejection inclination 3.31° north

Thanks!

Is it possible to add a calculation of UT more precisely in a second step after choosing a UT from the transfer plot?

And a calculation of best start inclination would be great if possible.

Edited by Kolago
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TriggerAu

TriggerAu

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Good to see people liking data :)

RasterProp sounds cool - I'll add it to the list, but no idea when I can get to it myself

I'd really like to be able to create nodes to help people out, but I will have to get some better maths skills to work it out. The best thing I've come across is to think of this tool - and all of them - as giving you a window of when efficient transfers occur, and some guidance on approx values for the ejection/injection, but I will do my best

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