Protractor - Rendezvous Plugin - Under New Management!

[amore555]

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.

Cheers guys, I'll try this one tonight

[Neomatt]

Cheers guys, I'll try this one tonight

Well, since then, the Closest Approach was added, so a new step is added:

4) check that distance when it's displayed. If it goes up after reaching a minimum, stop moving, try another axis, rinse and repeat until intercept.

You want to stay in the ballpark (<5 Gm) if you're not on the main trajectory (for example, if you're still in Kerbin's SOI for a trip to Duna), and then do corrections with RCS in mid-flight.

[Olsson]

I have the old version without the Closest Approach lines. I'm in orbit around kerbin atm and I need to go to Duna, my eject angle is 210.22 and my current eject angle changes all the time as I orbit around. I tried to start burning once I hit 210.22 eject angle and once I reached the amount of delta-v I needed I still wasn't in a Duna encounter trajectory, I'm doing something wrong, what is it? Can I keep my current eject angle somehow or?

[amore555]

Well, since then, the Closest Approach was added, so a new step is added:

4) check that distance when it's displayed. If it goes up after reaching a minimum, stop moving, try another axis, rinse and repeat until intercept.

You want to stay in the ballpark (<5 Gm) if you're not on the main trajectory (for example, if you're still in Kerbin's SOI for a trip to Duna), and then do corrections with RCS in mid-flight.

Sorry, I understand the games mechanics well, but am not necessarily familiar with the correct terms, try another axis?

[Neomatt]

Sorry, I understand the games mechanics well, but am not necessarily familiar with the correct terms, try another axis?

Sorry, I meant: if your navball is pointing at 90°, and you reached the minimum distance, try N/180° or normal/antinormal (the ones at the "top and bottom").

To test/affine those, I use RCS with H and N: H is "going in that direction", N is "going reverse". You can also use IJKL to try if translations are improving or not the distance.

And instead of using all my RCS fuel to go "forward", if H works, I cut off the RCS and thrust slowly (with one finger on X to cut everything when I reach the minimum).

Usually, if the target is not on my current trajectory (i.e. still on Kerbin's SOI while I'm going to Jool), I can reach about 5 or 10 Gm to the body. Then, I time-warp to the middle/two-thirds of the "road", and do the final corrections until intercept (and maybe a bit more to get a low periapsis, but you have to correct again once in the system, so you can just wait).

I have the old version without the Closest Approach lines. I'm in orbit around kerbin atm and I need to go to Duna, my eject angle is 210.22 and my current eject angle changes all the time as I orbit around. I tried to start burning once I hit 210.22 eject angle and once I reached the amount of delta-v I needed I still wasn't in a Duna encounter trajectory, I'm doing something wrong, what is it? Can I keep my current eject angle somehow or?

If you missed Duna with the old plug-in, it means you're close but still out of the SOI.

What you can try is to go at half the trajectory and do corrections in North/180° (to line up the trajectory with the orbit), or normal/antinormal (to move the center of your ellipsis).

It's much better to get the new plug-in however, since you know from a small push if you're going the right way or not.

Edited October 1, 2012 by Neomatt

[mrenigma03]

New update!

Changes in 2.2.2

- improved scaling of the closest approach line so as to be visible on the map when zoomed out

- tweaked ejection burn adjustment values to work with low thrust/mass ships

- adjust ejection now works for transfers between moons

- closest approach now styled to reflect distance - bold for close, bold and italics for intercept

- significantly improved GUI

- code optimization

[Olsson]

New update!

Changes in 2.2.2

- improved scaling of the closest approach line so as to be visible on the map when zoomed out

- tweaked ejection burn adjustment values to work with low thrust/mass ships

- adjust ejection now works for transfers between moons

- closest approach now styled to reflect distance - bold for close, bold and italics for intercept

- significantly improved GUI

- code optimization

I have a ship in orbit atm with a protractor calculator. If I update can I still use the ship and the calculator that's on it?

[mrenigma03]

I have a ship in orbit atm with a protractor calculator. If I update can I still use the ship and the calculator that's on it?

Yep!

I'll let you know if anything ever breaks backward compatibility.

[Olsson]

Right I'm doing something wrong cause it's not getting me into a Duna encounter. I wait until I'm at the Adjusted vessel eject angle then I burn prograde until my required delta-v reaches 0 and I'm just in an orbit around the sun -.- I suck.

[whatisthisidonteven]

Right I'm doing something wrong cause it's not getting me into a Duna encounter. I wait until I'm at the Adjusted vessel eject angle then I burn prograde until my required delta-v reaches 0 and I'm just in an orbit around the sun -.- I suck.

Duna's orbit is eccentric, you will need to do mid-course corrections most of the time.

[mrenigma03]

New update!

Changes in 2.2.2

- improved scaling of the closest approach line so as to be visible on the map when zoomed out

- tweaked ejection burn adjustment values to work with low thrust/mass ships

- adjust ejection now works for transfers between moons

- closest approach now styled to reflect distance - bold for close, bold and italics for intercept

- significantly improved GUI

- code optimization

- fixed crash related to 0 thrust/mass ratio and adjust psi

[Olsson]

Duna's orbit is eccentric, you will need to do mid-course corrections most of the time.

Then how am I supposed to know how to get to Duna? I don't even know what course corrections I'm supposed to be doing and when, I just burn at the time when it tells me too and that apparently won't get me there?

[mrenigma03]

Then how am I supposed to know how to get to Duna? I don't even know what course corrections I'm supposed to be doing and when, I just burn at the time when it tells me too and that apparently won't get me there?

No, the tool is designed as instrumentation. It has to use simplified versions of the orbits to do the math. The result is that it gets you 95% of the way just by following the numbers. That last 5% requires an understanding of space flight so you can make the necessary corrections. There are a lot of really good guides littered about the forums, and you can always join the #KSPOfficial channel and ask for help.

[amore555]

Sorry, I meant: if your navball is pointing at 90°, and you reached the minimum distance, try N/180° or normal/antinormal (the ones at the "top and bottom").

To test/affine those, I use RCS with H and N: H is "going in that direction", N is "going reverse". You can also use IJKL to try if translations are improving or not the distance.

And instead of using all my RCS fuel to go "forward", if H works, I cut off the RCS and thrust slowly (with one finger on X to cut everything when I reach the minimum).

Usually, if the target is not on my current trajectory (i.e. still on Kerbin's SOI while I'm going to Jool), I can reach about 5 or 10 Gm to the body. Then, I time-warp to the middle/two-thirds of the "road", and do the final corrections until intercept (and maybe a bit more to get a low periapsis, but you have to correct again once in the system, so you can just wait).

If you missed Duna with the old plug-in, it means you're close but still out of the SOI.

What you can try is to go at half the trajectory and do corrections in North/180° (to line up the trajectory with the orbit), or normal/antinormal (to move the center of your ellipsis).

It's much better to get the new plug-in however, since you know from a small push if you're going the right way or not.

Well, using your mod, and following your post like a tutorial, this complete inept fool has only gone and landed on Duna!! (kinda, see pic)

This mod is incredible, I've been waiting for something that makes it this simple to plan missions and yet still lets you fly it yourself!!

[Sbowyer28]

Most of these updates wont break old ships right?

[mrenigma03]

Most of these updates wont break old ships right?

Pretty sure any plugin version post 2.0.0 works on any ship built since 2.0.0 (1.x.x weren't even released on these forums).

I leave a lot of ships in certain orbits to test the mod, so I'd notice if it broke backwards compatibility. If that happens, I'll let you know. Unless it's a major feature update (or caused by Squad updating something), I wouldn't introduce anything that breaks old ships.

[Neomatt]

Well, using your mod, and following your post like a tutorial, this complete inept fool has only gone and landed on Duna!! (kinda, see pic)

This mod is incredible, I've been waiting for something that makes it this simple to plan missions and yet still lets you fly it yourself!!

That's what I like about it: you could get the same result by keeping a spreadsheet or calculator around you, and putting a protractor on the screen, but it's much nicer to have the values displayed (and still make all the burns/corrections by yourself).

I also use the map to be sure I'm not missing widely; if my apoapsis is on the planet's orbit (both viewed from the top and the side; you don't want to come in too low or too high), that's a very good indicator that I'm getting closer for the final, mid-course corrections.

And thanks, I tried to explain the best I could. Glad you landed once; I'm still trying to do a return trip here.

Edited October 1, 2012 by Neomatt

[amore555]

Yeah I have a ship on the way to rescue my guys from Duna, the command module uses RCS to put itself in an 80k by 80k orbit, help is on the way! This mod has made the game 5 x as fun for me

[Olsson]

Alright so I got to Duna. However once I got into orbit or an escape trajectory out of duna I had a very big inclination so I was like beneath Duna, not very efficient, how do I make sure this doesn't happen again. Also once I got into Duna I had a high velocity so I had to spend alot of fuel to slow down, how can I make sure that I use the least amount of fuel possible to get to Duna?

[mrenigma03]

Alright so I got to Duna. However once I got into orbit or an escape trajectory out of duna I had a very big inclination so I was like beneath Duna, not very efficient, how do I make sure this doesn't happen again. Also once I got into Duna I had a high velocity so I had to spend alot of fuel to slow down, how can I make sure that I use the least amount of fuel possible to get to Duna?

1) Land on Duna near its equator, then take off heading east (just like you would from Kerbin).

2) As far away from Duna as possible, start fine tuning your approach. The earlier you correct, the less fuel you have to use. Start tuning from Kerbin, then do more adjustments 10 days before you enter Duna SOI. This should leave very little work for you to do once you're in Duna's SOI. Eventually you want to aim to have a periapsis around Duna of between 9 km. and 10 km. Use parachutes. If you do it right, you won't have to spend a drop of fuel from your lander. If you're trying to get to Ike, use a periapsis of above 12 km. That will aerobrake you but not so much that you don't leave Duna's atmosphere. Mechjeb landing module predicts your apoapsis after an aerobrake, so use that as a guide.

[Olsson]

1) Land on Duna near its equator, then take off heading east (just like you would from Kerbin).

2) As far away from Duna as possible, start fine tuning your approach. The earlier you correct, the less fuel you have to use. Start tuning from Kerbin, then do more adjustments 10 days before you enter Duna SOI. This should leave very little work for you to do once you're in Duna's SOI. Eventually you want to aim to have a periapsis around Duna of between 9 km. and 10 km. Use parachutes. If you do it right, you won't have to spend a drop of fuel from your lander. If you're trying to get to Ike, use a periapsis of above 12 km. That will aerobrake you but not so much that you don't leave Duna's atmosphere. Mechjeb landing module predicts your apoapsis after an aerobrake, so use that as a guide.

I think you misunderstood my questions. 1) I got into an orbit around duna which was very inclined and not around the equator, I want to be able to come into Dunas SOI with a normal inclination around the equator. 2) How am I supposed to know where to fine-tune my approach if I'm not an interception trajectory with Duna even though I have the right Delta-V, Ejection Angle and all that?

[mrenigma03]

I think you misunderstood my questions. 1) I got into an orbit around duna which was very inclined and not around the equator, I want to be able to come into Dunas SOI with a normal inclination around the equator. 2) How am I supposed to know where to fine-tune my approach if I'm not an interception trajectory with Duna even though I have the right Delta-V, Ejection Angle and all that?

Ah, I did misunderstand, sorry.

1) You want to level out your approach so that you enter Duna's SOI at its equator with a 0 degree inclination. This is something you can do two weeks ahead of time (once you have an intercept course).

2) Use the "closest" column. It tells you how close your current orbit takes you to your target. Do a quick RCS thrust in each direction (right, left, forward, backward, up, down) and see which ones decrease that distance. Then burn in that direction. You can also click on the number and draw a line showing the closest approach, then try to make the green line shrink. Right now, the green line only works with another planet if you are orbiting the sun, but a future update will fix that.

[Neomatt]

Alright so I got to Duna. However once I got into orbit or an escape trajectory out of duna I had a very big inclination so I was like beneath Duna, not very efficient, how do I make sure this doesn't happen again. Also once I got into Duna I had a high velocity so I had to spend alot of fuel to slow down, how can I make sure that I use the least amount of fuel possible to get to Duna?

To correct your trajectory vertically, use N/180° as vectors on the navball before being near Duna. Or you can correct it in orbit if you like: just do your North/South burns when you're at the equator, North if your orbit gets you below the equator, South if... you get the idea.

For entry on Duna, since the atmosphere is not dense, you'll need a bit of 3 things:

1) parachutes. Definitely a safe, fuel-efficient way to slow down, with 2 caveats: max speed when they deploy (your craft must hold up), and how much they brake.

2) aerobraking. If you're coming from far away and real fast, you can lower your ship in the atmosphere; you'll see the trajectory take an orbit. Don't go too low, or you'll just end up landing.

3) powered descent. That's only on Duna right now: since the atmosphere is less dense than Kerbin, Eve, Laythe or Jool, your ship may still be going too fast before and after each deployment (aaaah, seeing the side parachutes "go up" at 200m from the ground...). You can do it with a slow burn, only to help the 2 other things. My target velocities are 1000m/s when the parachute is opening, but not fully deployed, 100m/s when it's fully deploying, and 5m/s when I'm touching ground.

Anyway, parachutes are a given if you're trying a planet/moon with an atmosphere.

[andygonzm]

Does the closest approach work with planetary eliptic orbits?

Edited October 2, 2012 by andygonzm

[mrenigma03]

Does the closest approach work with eliptic orbits?

Yes, closest approach takes inclination and eccentricity into account.

It's main purpose is as a way to fix the inadequacies of the angle functions caused by the angles ignoring eccentricity and inclination.