Question 3-95P4

The Iridium system utilizes a constellation of Low Earth Orbit (LEO) satellites to provide global telecommunications. Each Iridium satellite is equipped with an advanced phased array antenna that generates multiple highly directional spot beams. This design choice, where there are 48 spot beams per satellite, each covering an area roughly 30 miles in diameter, is crucial for several reasons: it allows for efficient frequency reuse, higher user capacity, and concentrated signal strength across the satellite's footprint on Earth. This "cellular" approach in space is fundamental to its operation. Option B is incorrect; the Iridium NEXT constellation consists of 66 active satellites (plus spares) in 6 orbital planes, not 48 in 4. Option C is incorrect as Iridium satellites operate in near-polar orbits with an inclination of approximately 86.4 degrees to provide global coverage, including the poles, not 55 degrees. Option D is incorrect; orbiting at about 780 km, their orbital period is approximately 100 minutes, not 85 minutes.