LEO (Low Earth Orbit)

Altitude: 160-2,000 km | Orbital Period: ~90-120 minutes | Latency: 20-40 ms

Examples: Starlink (550 km), OneWeb (1,200 km), ISS (408 km), Iridium (780 km)

Coverage: Small footprint per satellite; requires large constellations (hundreds to thousands) for global coverage

Advantages: Low latency, relatively low launch cost, high bandwidth per user

Disadvantages: Short visibility window per satellite (~5-10 min), requires satellite-to-satellite handoffs, orbital decay requires regular replacement

MEO (Medium Earth Orbit)

Altitude: 2,000-35,786 km | Orbital Period: ~2-12 hours | Latency: 100-150 ms

Examples: GPS (20,200 km), Galileo (23,222 km), GLONASS (19,100 km), O3b/SES (8,062 km)

Coverage: Medium footprint; 20-30 satellites for global coverage

Advantages: Good balance of coverage and latency, well-suited for navigation systems

Disadvantages: Higher latency than LEO, passes through Van Allen radiation belts (harder on electronics)

GEO (Geostationary Earth Orbit)

Altitude: 35,786 km (exact) | Orbital Period: 23 hours 56 minutes (matches Earth rotation) | Latency: 550-700 ms round-trip

Examples: HughesNet, Viasat, DirecTV, most weather satellites, GOES

Coverage: Each satellite covers ~1/3 of Earth's surface. Three satellites cover almost all populated areas.

Advantages: Fixed position in sky (no tracking needed), one satellite covers huge area, decades of proven technology

Disadvantages: Very high latency (unusable for gaming/VoIP), expensive to launch, orbital slots are limited and contested, poor polar coverage

Satellite signals pose no meaningful health risk to people on Earth

Verdict:

GPS signals arrive at 10^-16 watts. Even Starlink downlink (Ku-band) power density at ground is far below any safety threshold. The inverse square law over hundreds to thousands of kilometers reduces power to negligible levels.

Satellite internet user terminals are safe

Verdict:

Starlink Dishy transmits at ~2W (Ku-band uplink). FCC requires compliance with RF exposure limits. The phased array antenna directs energy skyward, not laterally. At normal mounting positions (roof), human exposure is minimal.

Satellite constellations affect astronomy but not health

Verdict:

LEO constellations cause light pollution (satellite trails in telescope images) and potential radio frequency interference with radio telescopes. These are real scientific concerns, but they are optical/electromagnetic interference issues, not health risks.