inclination mechanics

[rockbloodystar]

Hi,

I know that changing inclination is more efficient ar higher altitudes, but I have two inclination problems I am finding tricky to solve.

Is there a way to arrive at a planet's SOI at a desired altitude? Is this simple to predict and control?

Is there a way of calculating the correct maneuver to combine a apoapsis or periapsis shift with an inclination change at a suitable node?

Thanks in advance RBS.

[Sirrobert]

I don't know how to calculate it, but you could put a manouver node like halfway down the travel time and fiddle with it. Tiny changes can have big impacts down the line, and that will allow you to Finetune your exact arrival as you want.

However, you will need a mod that allows for extreme fine control over manouver nodes. Mechjeb has that function, and Precise Node mod is basicly all that.

What you can do with those, is make a manouver node, center the view on the target planet, and modify the manouver node from there. You can than see the exact effect of your changes in real time, and this allows you to make very fine modifications

[Alshain]

Most of the time you will get an encounter and then do a correction burn some distance later, you can do the correction burn anywhere but the further from your target, the amount of dV it requires may be so small that you miss by the time you cut the engines at 1% throttle. Even if you wait till just after you enter the sphere of influence to your target, it is a lot cheaper than doing it close to the planet.

[Tank Buddy]

For your first question, if you mean altitude as in the height of the periapsis for your flyby trajectory, then absolutely yes and yes. You can adjust your encounter by burning in a combination of directions: Radial, Anti-Radial, Prograde, and Retrograde. If you double click on a body (or right click and select "focus"), you will change the conic display mode and it will show your trajectory as it would appear if you were in it's SOI. This way you can see the results of burning in ^ these directions. Depending on your location relative to your target, each direction will have a different result. Once you get a feel of how it works, it becomes very easy to manipulate your intercepts. If you use KAC, set an alarm for 48 hours before your encounter; you can usually make minor changes easily then. Once you reach your target's SOI, you can burn North (0 degrees) or south (180 degrees) at the horizon to move your trajectory north or south. The same can be done for moving the trajectory east (90) or west (270).

Also note: The further you perform a maneuver from the target, the less DV you will need to expend to perform said maneuver. (this is not always so for plane changes, best done at low velocity and at Ascending/Descending nodes). This means it is best to fine tune your trajectory in your initial transfer burn, rather than later. If you use KAC, set an alarm for 48 hours before your encounter; you can usually make minor changes easily then.

For your last question, the maneuver nodes aren't very good with plane changes, but you can combine prograde/retrograde and Normal/Anti-normal burns.

[SAI Peregrinus]

KSP Trajectory Optimization Tool is the go-to program for calculating these sorts of things for KSP. You'll probably want the Precise Node and Kerbal Alarm Clock addons.

[OhioBob]

Is there a way to arrive at a planet's SOI at a desired altitude? Is this simple to predict and control?

It is best to perform a course correction while you're some distance out. When you are still a long way from the planet it is really hard to have fine control because the slightly velocity change has a big effect. I usually just try to get close, primarily focusing more on being in the correct plane than I am about getting the altitude right. Once crossing into the planet's SOI a final course correction can be made. At this time you can fine tune the altitude to be just what you need.

Is there a way of calculating the correct maneuver to combine a apoapsis or periapsis shift with an inclination change at a suitable node?

I suggest you take a look at the following. It gives equations for calculating the ÃŽâ€V of altitude changes, plane changes, and combination altitude/plane changes. If your answer isn't there then you can always ask a follow-up question.

http://www.braeunig.us/space/orbmech.htm#maneuver

[Sirrobert]

Most of the time you will get an encounter and then do a correction burn some distance later, you can do the correction burn anywhere but the further from your target, the amount of dV it requires may be so small that you miss by the time you cut the engines at 1% throttle. Even if you wait till just after you enter the sphere of influence to your target, it is a lot cheaper than doing it close to the planet.

A good tip on doing manouvers with extremely tiny amounts of deltaV, is to right click the engine and turn down the Thrust limiter all the way. This allows for much finer control over the amount of thrust you use

[Yakky]

A good tip on doing manouvers with extremely tiny amounts of deltaV, is to right click the engine and turn down the Thrust limiter all the way. This allows for much finer control over the amount of thrust you use

Or if you have RCS, do the fine-tuning with RCS rather than main engines.

[LordFerret]

Or if you have RCS, do the fine-tuning with RCS rather than main engines.

I do that with circular orbits setting up for SCANsat.

[Yasmy]

Hi,

Is there a way to arrive at a planet's SOI at a desired altitude? Is this simple to predict and control?

Thanks in advance RBS.

0) Prediction is already done and in game via the trajectory lines plus Pe markers.

1) Control: When you are far away from the target SOI, drop a maneuver node.

2) Hit Tab a bunch of times, changing your focus to the target. Now you can read your periapsis at the target.

3) Gently tug on the maneuver node handles to adjust your arrival.

4) If 3 doesn't work satisfactorily, move the maneuver node somewhen else.

5) Hit Backspace to target your ship again.

A maneuver node mod like PreciseNode or the one in MechJeb makes it very easy to design the perfect burn for your desired intercept.

[Sacs]

Hi,

Is there a way to arrive at a planet's SOI at a desired altitude? Is this simple to predict and control?

One trick: once you get the encounter click on the target and 'Focus View' & zoom in until you can see what your encounter looks like. You can then fine-tune it, though it can be a prick to get your maneuver node back up again. (It minimizes when you focus on another object which is a pain.)

To get a pro-grade orbit, you need to come in behind the target, for retrograde you want to enter SOI in fron