I have been toying with a java programming project for a few months now. I want to(adsbygoogle = window.adsbygoogle || []).push({});

depict a satelite orbiting a planet (2 dimensional).

I've scaled down certain constants to fit the screen and have put GM (mu) at 200000 and

the distance from the gravitaional body, a planet, at 200 (pixels). Using the equations

where a perfect orbital velocity is equal to sqrt(GM/dist), I must have a velocity of

sqrt(1000) 31.62 pixels/sec to remain in a circle.

Problem is my model depicts an ellipse.

The distance starts at 200, drops down to nearly 150 halfway around and climbs up again

(!!!) to 200 when it reaches the starting point. This is better than crashing into the

planet or flying away in a straight line...but still it should be a "perfect" circle.

I could understand it if my crude iteration method made a consistently "too small" or

"too big" quantity and cause the satellite to slowly spiral into the planet and crash or

caused the satellite to slowly spiral away from the planet. However the satellite

creeps down and then creeps up in a single orbit. Very strange. Why the wobble?

Yes, I am moving in singular one second steps around the planet and complete the orbit

in about 24 steps. And yes, if I took infinitely small steps an infinite number of

times, instead of a finite number of iterations, then I would come out with a perfect

circle. I am not Isaac Newton though.

Can I compensate in any way? Multiply the vector magnitude by sqrt(1/pi) or something

like that? Tilt the initial velocity vector away from the planet by 1/distance degree or

something?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# My satellite should go in a circle, not an ellipse

Loading...

Similar Threads for satellite should circle |
---|

I Integrate a function over a closed circle-like contour around an arbitrary point on a torus |

**Physics Forums | Science Articles, Homework Help, Discussion**