How to warp into Eve-Gravity-Influence in the correct angle?

[Sirine]

How to warp into Eve-Gravity-Influence in the correct angle? Seems every-time I warp in there, I ended-up around 0 ~30 Degree North pole.

I would like to make it to equatorial (90Degree) like normal standard Kerbin orbit does.

Any ideal?

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Here are the solution:-

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Edited September 4, 2013 by Sirine

[blizzy78]

You need to change your inclination mid-flight. Set Eve as your target, then watch out for the ascending/descending node markers. This is were you want to burn normal/anti-normal to correct your inclination.

[Sirine]

You need to change your inclination mid-flight. Set Eve as your target, then watch out for the ascending/descending node markers. This is were you want to burn normal/anti-normal to correct your inclination.

No. That will NOT solve the problem (in my case anyway) I have tested it many times. It always ended up "Above" Eve. Even the angle are "NaN".

[Johnno]

Entering SOIs at warp can cause changes in your trajectory. If you've set up a nice approach and then warp into the SOI your PE can be off hundreds of kilometers. My advice would be to turn off warp as soon as you enter the SOI and do a course correction then, it shouldn't cost much in delta-v and you'll want to anyway for aerobraking (unless you're doing a capture burn).

Or you can set up your approach and then turn off timewarp just before entering the SOI, then your trajectory should be unchanged, in theory anyway.

As for a foolproof way to set up an encounter and timewarp into the SOI and atmosphere to get into a perfectly equatorial orbit, I can't give you a way. I always do course corrections when necessary, part of my delta-v budget and to be expected.

[Scarecrow88]

I usually stop my warp 2 or 3 minutes before the SOI change and try and get a feel for where the intercept is going to be with relation to the target body. If I think it's going a bit high/low it's easier to change the further out you are.

[dimovski]

dont be so hard on the warp, you have to warp out slowly, and not just press "," xyz times till it slows you x1.

[Moar Boosters]

Like others have said, avoid changing warp when you're entering the SOI.

Warp most of the way, then zoom in, and slow down the warp so you enter the SOI in real time. The game does a bunch of calculations when you cross into the SOI, and if it's in warp, or worse..... changing warp modes, it can screw up the calculations and put you on a different course.

[Sirine]

Tested...even going in in real time x1, still end up above the Eve...Near North 0~10 degree.

[aNewHope]

The easiest way is to simply set your conics draw mode in the settings file to 0. This way you can perfectly see from where you will encounter the planet, what your inclination will be, and where your periapsis will be.

I know this picture is not perfect, but this is how your SOI changing trajectories would look like with "CONIC_PATCH_DRAW_MODE = 0"

[Motokid600]

Do yourself a great favor and get kerbal alarm clock for starters. It automaticly kills warp at a set time. ( I set it to kill warp 5 seconds before SoI change ). Takes all the guess work out of having to stop in time.

[Moar Boosters]

Tested...even going in in real time x1, still end up above the Eve...Near North 0~10 degree.

Show us a picture of the transfer you setup to get to eve, before you've flown out there. Especially the part where it shows your intercept.

[Sirine]

Here you go. The image all jumble up a little bit, due to multiple launch. Please state the one that interest you. So, I can redo the quest..

I'm going to get there AGAIN soon. With my Eve lander+lifter Mk2...(the Sea-Level Lifter), and brand-new interplanetary transporter.

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[Vector]

I too have noticed large inclinations when I reach Eve, and it is not the SOI transition that does it. The reason is the inclination of your approach does not match the inclination of Eve's orbit.

I see you are going pretty much straight from Kerbin to Eve and aiming for the AN or DN without adjusting inclination, (which is in my opinion the best way to do it). But this approach leaves you with a large difference in velocity between yourself and your target in the "vertical" direction (North/South, or normal as they call it). This large delta-V in the normal direction means you can never have a low inclination orbit when you arrive.

Inclination changes are costly, but if you were to do an experiment where you first match inclination with Eve's orbit, then I think you will find that when you reach Eve you will not have much normal velocity relative to Eve and your orbit around Eve will be nearly parallel to Eve's plane around Kerbol, or can be adjusted with small burns to be so. The inclination with the target planet will have to be very closely matched, because for planets even small differences in inclination correspond to really large delta-V at the ascending and descending nodes.

If Gillie weren't so tiny you could use it to cancel some inclination by swinging around "above" or "below" and leaving Gillie in the plane of Gillie's orbit. Gillie's orbital plane is closer to equatorial and would be an improvement if it were possible, but Gillie is not nearly massive enough for this to actually work. I mention it because this same idea does work on other planets.

[Sirine]

if you were to do an experiment where you first match inclination with Eve's orbit, then I think you will find that when you reach Eve you will not have much normal velocity relative to Eve and your orbit around Eve will be nearly parallel to Eve's plane around Kerbol, or can be adjusted with small burns to be so.

How? Make the AN or DN to -1 Degree or +1 Degree?

[SRV Ron]

When you go to make the mid course correction maneuver, activate the distance marker, parapsis, of the planet intercept. Then use the pink handles, up, down, and watch the distance change. Pull on those handles to reduce the distance. When that number reaches the smallest value possible, you will be in the proper plane.

Much harder to do is using a slingshot with one of the moons to re orientate to plane. Note how little change in Delta V was needed for a major orbital plane and slingshot braking that took place in that encounter with Ike.

Edited September 2, 2013 by SRV Ron

[blizzy78]

Which is exactly what I suggested in my first answer. OP's response was that it wouldn't help.

[SRV Ron]

I did land the Duna Ship on Eve. Given the extend of the oceans on that planet, it may be advantageous to be in an near polar orbit for landing. However, the Duna Lander doesn't have the delta V needed to get back into orbit.

[Sirine]

I did land the Duna Ship on Eve. Given the extend of the oceans on that planet, it may be advantageous to be in an near polar orbit for landing. However, the Duna Lander doesn't have the delta V needed to get back into orbit.

Well, I've made an Eve Sea Level Lifting craft.

From previous experience on Eve, I have to send 3 transporter to fetch back my Jeb... Due to the Angle problem. Wasted 2880 fuel ( 8 x LV-N) Just to turn to the right angle. And finally able to get him back to Kerbin safely. This time, I want to make it correct angle at the beginning.

[SRV Ron]

Well, I've made an Eve Sea Level Lifting craft.

From previous experience on Eve, I have to send 3 transporter to fetch back my Jeb... Due to the Angle problem. Wasted 2880 fuel ( 8 x LV-N) Just to turn to the right angle. And finally able to get him back to Kerbin safely. This time, I want to make it correct angle at the beginning.

If you can't get into the orbital plane you need, The closer you are to the edge of a planets SOI, the less delta v it will take to change orbital plane.

[Vector]

Thinking about this a bit, I realized it is also possible to use the planet itself to level out your inclination, but it is even more challenging than using a moon like Ike.

The idea is that you would do a non-capturing fly-by of Eve, entering at the inclined angle and leaving in the orbital plane of Eve. This is the easier part. The harder part is you have to adjust your exit such that your orbital period is very close to the orbital period of Eve, so that you can get a second encounter after one trip around Kerbol. On this second encounter you will be in Eve's orbital plane already.

This is going to be very challenging, and it takes another trip around Kerbol, but it will be very efficient if you can pull it off.

[Sirine]

I don't think so "Vector". Re-enter the Eve will only give you the same angle...No?

[Hannu]

As far as I saw, nobody said this. Make enough orbit corrections. When you leave Kebin's SOI, it is time to make first correction. If you use Mechjeb, you can use "fine tune closest approach" and/or Maneuver Node Editor in which you can enter velocity change as text. But it can be made manually too. Use that "SET_CONIC_DRAW_MODE = 0" -trick to see orbit around target planet. In that phase it is imporant to have encounter. It does not have to be (and it can not always be) accurate yet.

If you use plane change transfer one very important correction is at node point. There you burn normal direction until angle between planes is 0.0 (not more than 0.1). But typically ballistic transfers are more efficient. Use Alexmoon's excellent calculator and some vector math to get parameters of transfer.

In any case you should do one correction about half way. Then you should adjust periapsis within about 2-20 planet radius and maybe you can adjust inclination too. But it is not always enough. Next orbit check is about 5-10 days before encounter. It is good time to adjust periapsis and inclination to near final values by using normal and radial directions.

All SOI changes should do at most 100x time warp. Otherwise calculations are too inaccurate. It is good idea to check orbit then and make small corrections. In that phase you should not need more than 10 m/s. If you use manual maneuvers it is difficult to adjust 0.1 m/s scale values. Therefore it may be wise to make last adjustment at about 1000-2000 km from surface. If you do everything right midcourse correction can be 10-40 m/s and other corrections 0-10 m/s. However, plane change can be larger. It depends on orbital geometries of planets and not on accuracy of game's orbital calculations and burns.

I recommend Kerbal Alarm Clock and Mechjeb mods. They make things much easier. Even if you want to control everything manually, Mechjeb gives possibility to determine nodes much more accurate way.

[Sirine]

Thanks "Hannu". I read multiple times your post...But I do not understand. I'll try out the "SET_CONIC_DRAW_MODE = 0".

[blizzy78]

Thanks "Hannu". I read multiple times your post...But I do not understand.

What exactly did you not understand? Please elaborate.

It all comes down to doing mid-course corrections, the most important of which would be a plane change at the ascending/descending node. To which you replied it would not work.

[Sirine]

What exactly did you not understand? Please elaborate.

It all comes down to doing mid-course corrections, the most important of which would be a plane change at the ascending/descending node. To which you replied it would not work.

Okey...

1st. I'm not using any mod. Means no mechjeb.

2nd. Mid-course ascending/descending node. = NaN...already tested. And it won't work.

3rd. 5-10 days before encounter. That is impossible, if you using manual-all-the-way, you will know why. Because there is no more ascending/descending node for you to refer anymore. It just a line to the destination.

All SOI changes should do at most 100x time warp. Otherwise calculations are too inaccurate. It is good idea to check orbit then and make small corrections. In that phase you should not need more than 10 m/s. If you use manual maneuvers it is difficult to adjust 0.1 m/s scale values. Therefore it may be wise to make last adjustment at about 1000-2000 km from surface. If you do everything right midcourse correction can be 10-40 m/s and other corrections 0-10 m/s. However, plane change can be larger. It depends on orbital geometries of planets and not on accuracy of game's orbital calculations and burns.

Above, I do not understand. Warp in 1x. Not helping.

And the 10m/s? make adjustment 1000-2000km from surface? what surface? Mid-course correction? I just make the ascending/descending to be NaN. other correction 0-10 m/s? huh what? other correction? orbital geometries of planets? Ok. How to tell? what it refer to? How do I adjust? According to what?

Edited September 3, 2013 by Sirine