Shapes
Constellation shapes, and what each one buys
Four shell geometries that recur across the industry, each loaded into the calculator so you can see what the shape itself delivers before anyone argues about satellite counts.
- The Iridium pattern: 66 satellites, near-polarWhat a 66-satellite near-polar shell at 780 km delivers as idealised geometry: the classic pattern for global voice and messaging, including the poles.66 sats · 780 km · 86.4° · 6 planes · min elev 10°
- The Globalstar pattern: 48 satellites, mid-inclinationA 48-satellite shell at 1414 km and 52 degrees as idealised geometry: high altitude buying coverage per satellite, with a hard latitude ceiling.48 sats · 1410 km · 52° · 8 planes · min elev 10°
- The OneWeb pattern: 648 satellites, polarA 648-satellite polar shell at 1200 km as idealised geometry: what a dense high-LEO constellation delivers at every latitude, including above the Arctic Circle.648 sats · 1200 km · 87.9° · 12 planes · min elev 25°
- A dense broadband shell at 53 degreesThe shape most new broadband constellations reach for: a dense low shell at 53 degrees, sized for continuous service across populated mid-latitudes.720 sats · 550 km · 53° · 20 planes · min elev 40°
What to take from comparing them
The four differ in inclination, altitude, density and mask, and each difference buys something specific. Near-polar reaches the poles and thins the tropics. High altitude widens every satellite's footprint, which is the cheapest coverage available per spacecraft and the most expensive in link budget. Density closes the shell, but only at the end, and the last stretch buys the least visible improvement per launch. The elevation mask, which is a terminal decision rather than a space segment one, quietly sets how many satellites the whole plan needs.
Nothing here says anything about capacity, spectrum rights or licensing, which for a dense shell are usually the binding constraints. Geometry is the ceiling, not the service.