In this simulation three identical satellites move by gravity around a massive stationary object like the planets in the solar system. Assume that the attraction of the satellites for each other is much smaller than their attraction to the central object. At such conditions the motion of a satellite is described by the Kepler´s laws: 1.All planets move in elliptical orbits with the Sun at one focal point. 2.The radius vector drawn from the Sun to a planet sweeps out equal areas in equal time intervals. 3.The square of the orbital period of any planet is proportional to the cube of the semimajor axis of the elliptical orbit. By using floating band controls you can change satellites velocities and observe their motion in time that value puts in a box at upper right. To analyze trajectory for each satellite in detail you can learn the location of its tracks. If it is insufficient you can return satellites with help of Play back slider.