Iridium operates about 66 LEO satellites at roughly 780 km, offering truly global coverage including the poles with a one-way latency around 0.1–0.2 seconds. Inmarsat uses 3–4 GEO satellites at about 35,786 km, delivering near-global coverage (roughly ±70° latitude) with about 0.5 second latency, and IsatPhone 2 offers up to 8 hours of talk and…
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Starlink is SpaceX’s satellite-based broadband internet service, and by 2025 the constellation has launched over 7,500 satellites with about 6,750 active in orbit. The satellites orbit in low Earth orbit at roughly 550 km altitude, delivering typical download speeds of 50–200+ Mbps and latency around 20–40 ms. SpaceX began launching Starlink in 2019, and by…
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Traditional GEO satellite internet sends data roughly 22,000 miles to a satellite and back, yielding a round-trip latency of about 600–800 ms. Satellite internet can reach virtually anywhere with a clear view of the sky, including most of the continental United States. HughesNet uses geostationary satellites and advertises speeds up to 25 Mbps download and…
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Sputnik 1, launched by the Soviet Union on October 4, 1957, was the first artificial satellite. Explorer 1 became the United States’ first satellite in 1958. As of 2025, there are roughly 11,000+ active satellites orbiting Earth, with tens of thousands of pieces of inactive satellites and debris. Geostationary satellites orbit about 35,786 km (22,236…
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Bangladesh bans satellite phone use; possession can lead to arrest and imprisonment. North Korea prohibits all unauthorized communication devices, foreigners must surrender phones and privacy is not guaranteed, with detention possible. India restricts satellite phones to government‑approved Inmarsat devices, requiring a license (No Objection Certificate) from the Department of Telecommunications before bringing one in. China…
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Radar altimeters on TOPEX/Poseidon, Jason-1, Jason-2, Jason-3, and Sentinel-6 Michael Freilich have provided a global mean sea level record since 1992, showing a rise of about 3.3 millimeters per year and roughly 10 centimeters over 30 years. Arctic summer sea ice extent has declined by about 12% per decade since the 1980s, with the Arctic…
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As of 2025, Chad has about 2.74 million internet users (13.2% of the population), with roughly 87% of Chadians still offline. There are about 14.5 million active mobile subscriptions in Chad (roughly 70% of the population) in 2025, with many people owning multiple SIM cards. Chad has just one Internet Exchange Point in N’Djamena, and…
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DGNSS improves GNSS accuracy by using stationary reference receivers to broadcast corrections to rovers, transforming standalone GPS accuracy from about 5–15 m to sub-meter or centimeter levels, with SBAS like WAAS (USA) and EGNOS (Europe) delivering about 1–3 m for aviation. Real-Time Kinematic (RTK) uses carrier-phase measurements and double-differencing to fix integer ambiguities, delivering centimeter-level…
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As of early 2025, about 73.5% of Cape Verde’s population were internet users, roughly 387,000 people out of ~526,000. Fixed broadband subscriptions totaled about 38,000 in 2023, approximately 7 per 100 people. Cape Verde Telecom (CVTelecom) reported passing over 22,000 FTTH homes by the end of 2021, primarily in urban areas. There were over 600,000…
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GPS III, first launched in 2018, delivers three times the accuracy and eight times the anti-jamming performance of previous GPS generations, with a GPS III satellite named Katherine Johnson launched by SpaceX in 2025. GPS modernization includes the L1C common civil signal for interoperability with Galileo and a Next Generation OCX ground system to handle…
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