Satellites

Sputnik 1

Kepler's laws: 1. The Law of Orbits: All planets move in elliptical orbits, with the sun at one focus. 2. The Law of Areas: A line that connects a planet to the sun sweeps out equal areas in equal times. 3. The Law of Periods: The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit.

These laws apply not only to planetary orbits about the sun but also to satellite orbits as well.

Sources: http://www.aerospaceguide.net/satellite/sputnik_picture.jpg http://library.thinkquest.org/J0110163/sputnik_1.htm