Protractor - Rendezvous Plugin - Under New Management!

[mrenigma03]

Something on my to-do list is to make a pop up tutorial or separate manual or something.

[mikeallenbrown]

Well, that isn't what the directions say ... are they wrong then? ...says "then make Eject angle (third column) match your current eject angle on the bottom. So I can't really MAKE anything happen I just need to wait? Going back to my picture, had I waited a little longer I would have reached the 67.67 eject angle but then the phase & ren angles wouldn't have matched...is that ok, or does it all have to be exact?

-Mike

[mrenigma03]

Well, that isn't what the directions say ... are they wrong then? ...says "then make Eject angle (third column) match your current eject angle on the bottom. So I can't really MAKE anything happen I just need to wait? Going back to my picture, had I waited a little longer I would have reached the 67.67 eject angle but then the phase & ren angles wouldn't have matched...is that ok, or does it all have to be exact?

-Mike

My instructions are ambiguous, I'm realizing. You don't make the angles match, you wait. For any planet other than Moho, the phase angle changes really really slowly relative to the ejection angle. Consequently, your launch window is much longer. Moho is a pain because it's orbital period is really short. It may take a looong time until the phase angles and ejection angles perfectly match, so just try to get them close.

You want the phase angles as close as you can manage, but they don't have to be exact. Any deviation just means you may have to do a little more clever course correction to get there. Really the main goal of this plugin is to alleviate the need to consult an external website for suggested angles, and then to have to hold a protractor up to your monitor.

[Koschei]

Can you make it account for the orbital eccentricity? My last Duna mission just missed because Duna was at apoapsis.

[mikeallenbrown]

ok, got it ...thank you for the help!

-Mike

[mrenigma03]

Can you make it account for the orbital eccentricity? My last Duna mission just missed because Duna was at apoapsis.

I would love to, but I can't work out the math. It gets immensely more complicated when you move away from circular orbits. If someone wants to help with that, I'll add it in.

ok, got it ...thank you for the help!

-Mike

You're welcome - hope it helps!

If you're new to interplanetary transfers, Duna might be a better first shot than Moho. The SOI is tiny, but it has a relatively flat orbit. Plus its a ton easier to land on (bring parachutes, aim for a periapsis of 9 km).

Edited September 26, 2012 by mrenigma03

[segaprophet]

This is great - way better, more simple/minimal than the other mod!

Thank you for this!

[Grizzlol]

I do not understand. When on Kerbin, Mun and Minmus show no ejection angle. Is this a missing feature?

Very useful mod, though.

[mrenigma03]

I do not understand. When on Kerbin, Mun and Minmus show no ejection angle. Is this a missing feature?

Very useful mod, though.

There's no ejection angle because you don't need one. You only need the phase angles. Ejection angles are only for going between two bodies that orbit a common, third body (e.g. two planets and sun, two moons and planet).

[mrenigma03]

New version.

Changes in 2.1.5

- changed GUI theta to psi symbol for ejection angles to distinguish from phase angles

- added in-game manual

- when orbiting moon, phase angles to planets shown relative to moon's reference body

[Stalvet]

Fine mod. Thanks

[Stalvet]

little bug: delta V not show with "-" if needed slowing

[zarniw00p]

Great mod, this really helps a lot with interplanetary travel.

There's only one little issue: everytime when 2 ships that both are equipped with the protractor rendevouz or land near each other, I can't minimize the Planetary Rendevouz System window.

[mrenigma03]

little bug: delta V not show with "-" if needed slowing

Could you provide a screenshot please?

Great mod, this really helps a lot with interplanetary travel.

There's only one little issue: everytime when 2 ships that both are equipped with the protractor rendevouz or land near each other, I can't minimize the Planetary Rendevouz System window.

Hmm, I'll look into this.

[amore555]

Hi there, interested in this mod. I don't use Mech Jeb, and also never used any of the other rendezvous mods because they assume a level of maths that I simply don't have. In all honesty, how useful would this be to someone who doesn't consider the 'numbers and angles' for flight. Will I understand this?

[Neomatt]

Hi there, interested in this mod. I don't use Mech Jeb, and also never used any of the other rendezvous mods because they assume a level of maths that I simply don't have. In all honesty, how useful would this be to someone who doesn't consider the 'numbers and angles' for flight. Will I understand this?

Very useful.

Now you have the numbers for planets, and yours. So all you need to do is:

1) warp before liftoff until your angle (theta) is equal to the one of the planet you target,

2) lift-off, reach orbit,

3) when your ejection angle is equal to the one for the planet you target (+- 2 or 3 degrees if you do a slow burn), you burn apoapsis until you reach the correct delta-V.

If you missed the planet, it's because the angle was not 100% 0° (either for your ship or the planet), so a few RCS adjustments may be needed.

edit: to be clear, this does all the math, but since you don't reach the good speed/angle manually, you still need to fly by the seat of your pants a bit; it just gives the optimal fuel-efficient trajectory, not a sure-fire way to reach the planet.

Edited September 28, 2012 by Neomatt

[Stalvet]

Could you provide a screenshot please?

Hi, will try to make a video today.

[burnie]

Great plug-in! Very easy to understand and seems accurate. Even managed to transfer to Minmus from Mun using the numbers it suggested.

This will be a part of every rocket I build from now on

Thanks for sharing!

[mrenigma03]

Hi there, interested in this mod. I don't use Mech Jeb, and also never used any of the other rendezvous mods because they assume a level of maths that I simply don't have. In all honesty, how useful would this be to someone who doesn't consider the 'numbers and angles' for flight. Will I understand this?

Assuming you can get your ship into a basic, flat, circular orbit, you don't have to do any math at all. You literally only need to be able to wait until two numbers are the same. The plugin does all the math and measuring for you.

Great plug-in! Very easy to understand and seems accurate. Even managed to transfer to Minmus from Mun using the numbers it suggested.

This will be a part of every rocket I build from now on

Thanks for sharing!

Quite welcome!

[mrenigma03]

New version!

http://www.kerbal.net/mod.php?id=36"]Changes in 2.2.0

- New! Calculate closest approach. Works for planets and moons in your same system and planets in your next system if on an escape trajectory.

- New! Toggle to adjust ejection angle based on thrust-weight ratio to eliminate need to burn early

- Fixed menu bug caused by two protractors on two nearby ships

[whatisthisidonteven]

Well that update convinced me! AdamKSP served me well, but the TWR adjusting sold it for me.

Thanks!

[segaprophet]

New version!

http://www.kerbal.net/mod.php?id=36"]Changes in 2.2.0

- New! Calculate closest approach. Works for planets and moons in your same system and planets in your next system if on an escape trajectory.

- New! Toggle to adjust ejection angle based on thrust-weight ratio to eliminate need to burn early

- Fixed menu bug caused by two protractors on two nearby ships

Well met! You win the contest, good sir!

[adammada]

Well that update convinced me! AdamKSP served me well, but the TWR adjusting sold it for me.

Thanks!

I started using it by myself earlier . I just wanted to add "closestApproach" to it, so i could add it to Protractor Mod, but i see that mrenigma03 just added it ( but, @mrenigma03 - you could answer my PM about adding mine code to Protractor... )

I see that code already has LineRenderer, only commented out. Mine sugestion - just draw one line between closest ship and planet position. I was drawing many lines because i didn't had function which could find when preciselly will it be.

[mrenigma03]

I started using it by myself earlier . I just wanted to add "closestApproach" to it, so i could add it to Protractor Mod, but i see that mrenigma03 just added it ( but, @mrenigma03 - you could answer my PM about adding mine code to Protractor... )

I see that code already has LineRenderer, only commented out. Mine sugestion - just draw one line between closest ship and planet position. I was drawing many lines because i didn't had function which could find when preciselly will it be.

See your PMs. I'd love to add your linerenderer code to my plugin, with a couple tweaks.

[Grizzlol]

The TWR toggle can produce negative angles.