The recently inaugurated Globalstar and Sirius constellations use Walker patterns and other constellations such as GPS have also made use of this concept. This paper discusses rules to assist in the rapid selection of Walker patterns for new candidate constellations to provide earth coverage. Emphasis is placed on minimizing the number of orbital planes to facilitate constellation establishment with a minimum number of launches, to minimize the number of dedicated spares required for on-orbit support, and to facilitate on-orbit servicing of satellites as servicing capabilities develop. Low-altitude, circular and highaltitude elliptical orbits are studied