The satellite orbits the selected central body. Vis-viva gives its speed: v = √[μ(2/r − 1/a)]. Here μ is the body’s gravitational parameter, r is distance from its center, and a is half the ellipse’s long axis. Eccentricity sets how stretched the orbit is. True anomaly is the satellite’s angle measured from its closest approach. Move that slider to inspect any point, or pause the animation to hold it there.

The satellite speeds up near its closest point and slows down near its farthest point. Playback compresses each orbit to 16 seconds; the calculated period appears below. The model excludes atmosphere, thrust and other bodies. Planet and satellite symbols are not to scale.