How many orbital planes do Iridium satellites use?

• A. 2 orbital planes.
• B. 6 orbital planes.
• C. 8 orbital planes.
• D. 4 orbital planes.

Answer: (D)

Iridium achieves global coverage by organizing its satellites into multiple orbital planes. The constellation uses six orbital planes, evenly spaced around the Earth in near-polar orbits. This setup ensures that at any given time there are satellites visible from most locations, allowing reliable handoffs as satellites move across the sky. In the traditional 66-satellite configuration, there are 11 satellites in each plane, totaling 66. Having six planes provides better coverage, especially at higher latitudes; using fewer planes, like four, would create larger gaps in coverage and fewer satellites available for a connection at any moment.