Inclination help

[Jonda]

I have a mun station and I’m planning to make more/add to it or on other planets but I sometimes have trouble with Delta-v bec of the inclination bec the orbit isn’t completely flat is there a mod to fix this so I can save fuel or any tips???

[Snark]

Moving to Gameplay Questions.

59 minutes ago, Jonda said:

I have a mun station and I’m planning to make more/add to it or on other planets but I sometimes have trouble with Delta-v bec of the inclination bec the orbit isn’t completely flat is there a mod to fix this so I can save fuel or any tips???

By "mun station" I assume you mean that it's orbiting the Mun?

How inclined is its orbit (i.e. how many degrees)? Why not just adjust the station's orbit so it's not inclined? Then it will become easier to rendezvous with it.

You can adjust the orbit inclination by thrusting At the point where the orbit crosses the Mun's equator southbound,  or Where it crosses northbound.

Or, if it's all too difficult and you want to just skip figuring out how to do it in-game, you could use the "set orbit" cheat menu to force the inclination to be zero. It's up to you.

[Vexillar]

(ninja'd)!  Yup - what @Snark said...  If you're having trouble figuring how to match inclination with the station, then use those burns at the Ascending and Descending nodes (choose the station as target and you'll see AN and DN in the map view).  Or if you just want to get the station into a Munar equatorial orbit to save you aligning each visiting craft, use the cheat Alt-F12 menu.

[Jonda]

1 hour ago, Snark said:

Moving to Gameplay Questions.

By "mun station" I assume you mean that it's orbiting the Mun?

How inclined is its orbit (i.e. how many degrees)? Why not just adjust the station's orbit so it's not inclined? Then it will become easier to rendezvous with it.

You can adjust the orbit inclination by thrusting At the point where the orbit crosses the Mun's equator southbound,  or Where it crosses northbound.

Or, if it's all too difficult and you want to just skip figuring out how to do it in-game, you could use the "set orbit" cheat menu to force the inclination to be zero. It's up to you.

 

58 minutes ago, Vexillar said:

(ninja'd)!  Yup - what @Snark said...  If you're having trouble figuring how to match inclination with the station, then use those burns at the Ascending and Descending nodes (choose the station as target and you'll see AN and DN in the map view).  Or if you just want to get the station into a Munar equatorial orbit to save you aligning each visiting craft, use the cheat Alt-F12 menu.

The station is exactly 0 degrees. Sometimes my inclination will be off by like -50 or over depending on orbit im just wondering if you can figure out when its a good time to burn to the moon to get almost a 0 degree orbit inclination 

[Snark]

6 minutes ago, Jonda said:

The station is exactly 0 degrees.

Wait, so, you're saying that the station is already in an equatorial orbit?

Ah, okay.  I misunderstood your initial question post, above-- it sounded like you were saying "Help, my Mun station is in an inclined orbit, so it's a pain that all of my rockets have to match inclination to it each time."

6 minutes ago, Jonda said:

Sometimes my inclination will be off by like -50 or over depending on orbit

How so?  Could you provide a screenshot or something?  I totally get that you've got a problem, but I'm having trouble picturing what it is.  If the station is in an equatorial orbit... and the Mun itself is in an equatorial orbit... and you're launching your ships into equatorial orbit from KSC (right?)... where's the problem?  Wouldn't they already just be naturally lined up for a rendezvous with the station?  How are your ships getting into a 50-degree inclination in the first place?

[Jonda]

The muns orbit isn’t perfectly flat tgars why i have inclination problems 

[Plusck]

35 minutes ago, Jonda said:

The muns orbit isn’t perfectly flat tgars why i have inclination problems 

No, no, the Mun's orbit is perfectly equatorial, with respect to Kerbin. In that it is quite different from the Earth's moon.

However, it is very easy to end up capturing at the Mun on a highly inclined orbit due to a very small deviation from the equator on leaving Kerbin.

The answer is simply to plot a correction burn about halfway out to the Mun. Even a very big inclination can be fixed with only a few dozen m/s. In addition, if you play about with the radial and prograde sliders, you can easily make it so that your insertion happens exactly where your orbiting station will be, so you can rendezvous with it as soon as you arrive.

[Snark]

1 hour ago, Jonda said:

The muns orbit isn’t perfectly flat

Yes, it is... or are you running some mod that makes it different?

[Jonda]

1 hour ago, Plusck said:

No, no, the Mun's orbit is perfectly equatorial, with respect to Kerbin. In that it is quite different from the Earth's moon.

However, it is very easy to end up capturing at the Mun on a highly inclined orbit due to a very small deviation from the equator on leaving Kerbin.

The answer is simply to plot a correction burn about halfway out to the Mun. Even a very big inclination can be fixed with only a few dozen m/s. In addition, if you play about with the radial and prograde sliders, you can easily make it so that your insertion happens exactly where your orbiting station will be, so you can rendezvous with it as soon as you arrive.

Oooh okay that makes sense thank you!

[OhioBob]

Mun's orbit around Kerbin is perfectly equatorial, but your parking orbit around Kerbin is not.  The launch pad is just very slightly south of the equator, which means you'll end up in a very slightly inclined orbit around Kerbin.  So a trajectory that takes you to Mun could end up placing you in an inclined orbit around Mun.  However, my experience is that the inclination typically isn't all that much; 50 degrees sounds like an awful lot to me.

There are a couple solutions.  One is to make sure your orbit around Kerbin is perfectly equatorial before performing your transfer burn.  You can also perform a midcourse correction as @Plusck describes.  Although a midcourse maneuver can correct most error, it still doesn't assure that your orbit at Mun will be perfectly equatorial.

The final piece to the puzzle is this:  When you perform the midcourse correction, make sure the periapsis of your approach trajectory is located exactly in the plane of the target orbit.  This assures that when you reach periapsis and have to perform your orbit insertion burn, you'll be passing through the plane of the orbit of your space station.  You can, therefore, add a normal/anti-normal component to your insertion burn and correct the plane at the same time.  If properly executed, you should be able to match the orbital plane of the space station with very little error.

[GRS]

Reminds me of the old myself, i never used course correction burns, so end up in a Mun pole landing (kinda), you need to look carefully to see inclination of your future orbit, or change inclination in a high orbit.