Fix dollar signs + add descendants section

# [TECH] Satellite Communications

**Satellite Communications** uses spacecraft in geosynchronous and low Earth orbit to relay telecommunications signals globally, enabling intercontinental telephony, television broadcasting, internet, and navigation.

## Overview

Arthur C. Clarke proposed geosynchronous communication satellites in 1945. Telstar 1 (1962, AT&T/Bell Labs) was the first active communication satellite. INTELSAT I (Early Bird, 1965) carried 240 telephone circuits. Ku-band direct broadcast (1970s–80s) enabled satellite TV. Low Earth Orbit constellations (Iridium 1998; Starlink 2019–) provide low-latency broadband globally. GPS and Earth observation satellites are also communication-technology descendants.

## Key Actors

- **Companies**: INTELSAT (1964), AT&T/Bell Labs, Hughes Aircraft, SES (1985), SpaceX/Starlink (2019), OneWeb
- **Inventors**: Harold Rosen (1926–2017, geosynchronous satellite pioneer)

## Key Patents

- Rosen, H. et al. US Patent 3,653,627 (1972) — spin-stabilised geostationary satellite

## Economic Value

Global satellite communications market: **\$125 billion/year** (2023, NSR). Including satellite manufacturing, launch, and services. Starlink alone targets \$30B/year revenue by 2025 (SpaceX internal projection).

## Notes

NSR *Satellite Communications Market Report* 2023. GPS (separate node) adds \$2T+/year but is primarily navigation rather than communications.

## What This Enables
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- **[TECH] Internet & World Wide Web** — Early internet backbone used satellite links; Starlink (2019–) now provides rural and maritime broadband.
- **[TECH] Mobile Phones & Smartphones** — Satellite positioning (GPS) and backhaul support cellular network infrastructure worldwide.
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# Parents

* [TECH] Rocket & Space Launch
* [TECH] Radio & Wireless Communication
* [TECH] Jet Engine
* [TECH] Rocket & Space Launch