Discussion Looking for easier way to create new eliptical orbits.

[ncc1701d]

perhaps it is very amature of me but I am a beginner with orbital mechanics. I wish there was an addon that let you create simple eliptical orbits for new ships.
Where you create an elipse shape using Semi-major axis and also Semi minor axis values. Then let you pick which of the 2 foci of the elpse to have the planet. Then set the inclination angle. Then other options I might need that are important that I might be missing.

The videnie orbital line display would allow you to see the ellipse in orbiter.

I want my eliptical orbit to Look a certain way and many of the numerical inputs in the Scenario editor are hard to visualize.
It would only be for simple eliptical orbits that are periodic and would not even degrade because of gravity becuase they are so basic.
What do others think of this idea? helpful? yes or no?

 

[Bonanza123d]

Create an elipical orbit with an ecc 0 is easy, just burn at the PeR and ApR

 

[N_Molson]

An ellipse with an eccentricity of 0 is a circle, no ? :hmm:

Else you can try to disable "nonspherical gravity sources", and set a lower hard limit to Earth atmosphere...

Or try to orbit a (dwarf) planet that has no significant atmosphere and no moons (tidal effect), like Mercury or Pluto.

 

[ncc1701d]

dont think I understand you or you me.
I have an almost circular elipse eccentricity .0009.

I hava model of a cube. No thrusters. No power. Nothing but a mesh.
I am interested in it have a more eliptical shaped path but I was hoping to have a semi minor axis numerical imput area in the scenario editor so I can create the shape of orbit I want. Your talking about burns etc and I dont have power. Just a mesh I want to put in orbit that is good for minimum couple good trips before gravity sends it crashing. Other numerical input areas in the scenario editor like (LAN) may effect shape of elipse but by putting randomly numbers I get to unpredictable results for the shape of my elliptical path.

 

[boogabooga]

perhaps it is very amature of me but I am a beginner with orbital mechanics. I wish there was an addon that let you create simple eliptical orbits for new ships.
Where you create an elipse shape using Semi-major axis and also Semi minor axis values. Then let you pick which of the 2 foci of the elpse to have the planet. Then set the inclination angle. Then other options I might need that are important that I might be missing.

The videnie orbital line display would allow you to see the ellipse in orbiter.

I want my eliptical orbit to Look a certain way and many of the numerical inputs in the Scenario editor are hard to visualize.
It would only be for simple eliptical orbits that are periodic and would not even degrade because of gravity becuase they are so basic.
What do others think of this idea? helpful? yes or no?

You say several things that don't make sense. If you want to learn this, you have to understand the terminology and what each element defines rather than expecting someone to cater to your own definition of elements.

Where you create an elipse shape using Semi-major axis and also Semi minor axis values.

Semi-major axis you appear to understand. Semi-minor axis has limited value on its own. Eccentricity is more useful. The semi-minor axis can be deduced from semi-major axis and eccentricity. Eccentricity and S.M.A . together define the size and shape of the orbit.

Then let you pick which of the 2 foci of the elpse to have the planet.

Ellipses are symmetrical. There is no difference between the foci. What you're trying to understand is the orientation of the ellipse in space. Try changing the argument of periapsis to 180 from its current value. Is that the effect you wanted to see?

It would only be for simple eliptical orbits that are periodic and would not even degrade because of gravity becuase they are so basic.

I want to put in orbit that is good for minimum couple good trips before gravity sends it crashing.

Gravity does not degrade orbits, per se, at least not how you're thinking. (Air drag will.) You misunderstand even the most basic concept of orbit- you are in a freefall around the planet. Without external forces this would keep going forever.

Other numerical input areas in the scenario editor like (LAN) may effect shape of elipse but by putting randomly numbers I get to unpredictable results for the shape of my elliptical path.

No kidding.

Here, read this:
[ame="http://en.wikipedia.org/wiki/Orbital_elements"]Orbital elements - Wikipedia, the free encyclopedia[/ame]

Take a systematic approach, not a random one.
Try to understand each element, one at a time. Change it in the scenario editor in smooth increments and observer the results in videnie.

 

[ADSWNJ]

I think all you need is a way to map whatever parameters you want to use into the standard 6 orbital elements on the Scenario Editor. Let's recap the standard ones and then see how close we are:

1. Semi-major Axis (SMa)
2. Eccentricity (Ecc)
3. Inclination (Inc)
4. Longitude of Ascending Node (LAN)
5. Longitude of Periapsis (LPe)
6. Mean longitude at epoch (eps)

I think of these as follows:

The SMa is the long radius of the oval, and the Ecc says how oval it is. The Inc pitches up the oval wrt your planet's equator (or ecliptic). The LAN yaws the oval around the planet's poles to ascend over the equator (ecliptic) where you choose. The LPe rotates the oval such that the periapsis is where you want it (or in other words, yaws the oval on it's own axis to where you want it). Finally the eps sets your position on the oval at an instant in time (the epoch), so you can calculate the actual position at any other time. Note the first 5 specify the oval, and the 6th is your position, so if you just want the oval, you only need the first 5.

On your elements: looks like you like SMa, SMi, and Inc. SMi is another way to express Eccentricity, and it's easy to convert directly between the two. So all you need to do is to choose the LAN and LPe. Think of looking down on the north pole of the planet (on one of your focal points): pick your angle where the oval comes up into your hemisphere (LAN), and the angle for the closest point (periapsis) and you are done.

Not sure if that helped?

 

[ncc1701d]

boogabooga
"You say several things that don't make sense."
This is true...I am a beginner. I have to ask questions even if they sound strange to the experienced so I can hopefully learn.

"argument of periapsis set to 180 from its current value"
Yes this is the effect I need. Thank you boogabooga.

---------- Post added at 12:44 AM ---------- Previous post was at 12:39 AM ----------

ADSWNJ
thanks for breaking it down more simply.

 

[goaowonk]

Tex made a nice tutorial video about orbit parameters & orbit MFD that may help you. Check it out at his youtube channel, Texfilms .

Sent from my Deltaglider using Potatolk.

 

[Ripley]

Here it is: