Change in Inclination/Orbital Plane Increases Semi-Major Axis? Is This Normal?

5kinflute

New member
Joined
Dec 15, 2016
Messages
4
Reaction score
2
Points
3
Good morning,

I am simulating an orbit around the lunar / seline celestial body but I ran into a problem where changing inclination / declination massively increases the semi-major axis or apoapsis height even at a slightly small change in inclination / declination angle


I attached an image showing my initial & final orbit of my observation. The satellite is at periapsis with a velocity of 1708 m/s and I applied about 6 N of thrust for a normal + burn to increase declination angle. My goal is to at least have a 45 degree inclination orbit around the moon but this causes my orbit to be more elliptical rather than circular -- and this is a big problem for me now because my altitude is now too high ( I want to maintain at least 100 km altitude )

I decided to jump in Orbiter 2016 and detached from ISS and did a similar burn ( anti-normal - ) and it shows my apoapsis reaching 1.693 M which is a bit a relief for me because I thought I was going crazy... but here I achieved an inclination change all the way down to 139 degrees with unlimited fuel turned on... but in the moon I only got 0.0917 degrees ! if I try to go any HIGHER my orbit becomes hyperbolic!

Is this normal in the moon ? How does other space agencies get around this?

P.S. my source code might have errors which I am still investigating but just wanted to share this post for anyone else having this problem...

UPDATE


After some pondering, walking my dog outside, and tossing / turning in my bed ... the position z vector is actually 0 an orbital plane; non-zero when calculating inclination & declination...it's really all about perspective

[math]\frac{x^{2}}{a^{2}}+\frac{y^2}{b^2}[/math]
 

Attachments

  • inclination change help plz.png
    inclination change help plz.png
    227.2 KB · Views: 17
  • y.png
    y.png
    128 KB · Views: 17
Last edited:

n72.75

Move slow and try not to break too much.
Orbiter Contributor
Addon Developer
Tutorial Publisher
Donator
Joined
Mar 21, 2008
Messages
2,672
Reaction score
1,329
Points
128
Location
Saco, ME
Website
mwhume.space
Preferred Pronouns
he/him
You sure your burning normal+ with respect to your Orbiter around the moon and not the sun or earth? Double check the HUD.
 

5kinflute

New member
Joined
Dec 15, 2016
Messages
4
Reaction score
2
Points
3
Ah I finally figured out what was going on; I had to ask a dumb question to get there... updated my post..
 

Urwumpe

Not funny anymore
Addon Developer
Donator
Joined
Feb 6, 2008
Messages
37,564
Reaction score
2,298
Points
203
Location
Wolfsburg
Preferred Pronouns
Sire
Also, you can of course have a change in your apsis nodes while changing your inclination a lot. A 180° change would essentially be about stopping and then accelerating again in the opposite direction...
 
Top