Periapsis and apoapsis changing itself

General_Mile_1

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Hello there, every time I try to go in far from earth orbit (still in its sphere of influence) my apoapsis and periapsis is moving, and after I complete orbit, it moved from 200 km to 20 000 km (aproximatly) and I dont know what is causing this
 

N_Molson

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It is normal and realistic.

Your spacecraft is subject to the gravitational pull of the Earth, but also the Moon, the Sun, even Jupiter and the other planets... This is what one call "the n-body problem". Any decent navigation MFD will take this in account. If you have played KSP before, well KSP is a very simplified gravity model, Orbiter is much more realistic.

A clue is the "0.99 G" readout you have below Orbit MFD. 1.00 means that you are completely under Earth gravitational influence. As this number decreases, it means that other celestial bodies are pulling on you.

Still, you'll find out that a high orbit (like the Geo-Stationary Orbit) is quite stable, as atmosphere expands to LEO, causing friction.
 

N_Molson

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What do you want to do ? TransX or other navigation MFD can compute accurately your trajectory to navigate anywhere inside the Solar System.
 

General_Mile_1

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I know but transx is not working for me, when I set course for another planet, when I speed up time, closest approach distance starts to change and I miss by long distance, I dont know why
 

N_Molson

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I know but transx is not working for me, when I set course for another planet, when I speed up time, closest approach distance starts to change and I miss by long distance, I dont know why

You probably have to make mid-course corrections, Mars probes do a couple of those in real life. Apollo did that too. You aim at a very little target from very very far away. The distances and numbers involved are huge.
 

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Hi !
I don't use TransX, i use Interplanetary MFD (IMFD). A good advice for a direct mars mission is : make a correction as soon as you're out of Earth's SOI. Then, when you do the plane correction (if needed). After i use a trick : i look regularly at the AutoBurn (AB) screen. The burn duration could grow during the flight. When it becomes stable, i do the burn. It's often enough to be OK until i start the Planet Approach program. But sometimes, 3 or 4 corrections are needed. Sometimes, the post SOI burn is enough. As N_Molson said, a lot of things interfere in your trajectory : gravitational influences, vessels' thrust, MFD's computings, pilot's patience... In Orbiter, you can't simply do the burn and let it go until arrival. You have to keep an eye on the numbers during the flight. There are good tutos on YT about IMFD, in english. Don't forget to save your game after very step. Some addons provide multiple scenarios for one mission, so you can train yourself step by step, from launch to arrival / landing. I hope those advices could help you.
 
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