A constellation, including a plurality of spacecraft, including a first,
second and third spacecraft, each of the plurality of spacecraft
including a broadcast capability, and each of the plurality of spacecraft
in its own approximately 24-hour orbit. Each of the orbits has a
substantially teardrop-shaped or oval-shaped ground track, is optimized
based upon elevation angle or probability of signal availability, and has
an apogee longitude of approximately 90.degree. west to approximately
100.degree. west. Each of the orbits has a semi-major axis of
approximately 42,164 kilometers, an argument of perigee of approximately
270.degree., an inclination of approximately 40.degree. to approximately
60.degree., and an eccentricity of approximately 0.16 to approximately
0.4. The orbits of each of the plurality of spacecraft are selected to
bring each of the spacecraft to apogee at time increments of
approximately eight hours.