In 2024 the global space economy reached $415 billion, with commercial satellite activities totaling about $293 billion (71%). The number of active satellites rose from about 3,300 in 2020 to over 11,500 by end-2024 due to mega-constellations. SpaceX and OneWeb have joined traditional players like Airbus, Boeing, Lockheed Martin, Thales Alenia, Intelsat, SES, Eutelsat, and…
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As of mid-2025, Starlink is available in over 110 countries and territories. In the United States, Starlink began with limited trials in August 2020 and the public beta “Better Than Nothing Beta” in November 2020, and now has nationwide commercial coverage including Puerto Rico and the U.S. Virgin Islands, with over 2.5 million subscribers as…
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The first space images were captured in 1946 from a sub-orbital U.S. V-2 rocket at about 105 km altitude. The first actual satellite photograph of Earth was taken on August 14, 1959 by the U.S. Explorer 6 satellite. In 1960, TIROS-1 transmitted the first television image of Earth from orbit, a milestone for weather observation.…
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About 75% of the planet is obscured by cloud cover or darkness at any moment, making optical imaging inaccessible. Synthetic Aperture Radar (SAR) satellites actively illuminate the ground with microwave radar and synthesize a large aperture by moving the antenna to produce high-resolution images. SAR can operate day or night and in all weather, providing…
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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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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 mid-2025, Starlink operates about 7,500 active satellites, the largest fleet in history, accounting for more than 60% of all active satellites. Starlink’s next-generation satellites (v2) weigh about 800 kg each, vs 260 kg for v1, and use inter-satellite laser links to route data across continents. Amazon’s Project Kuiper plans 3,236 LEO satellites at…
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GSSAP-1 and GSSAP-2 were launched on July 28, 2014 aboard a Delta IV M+(4,2) from Cape Canaveral, accompanied by the ANGELS experimental satellite. The GSSAP satellites operate in near-geosynchronous orbit roughly 35,900 km (22,300 miles) above Earth and function as a “neighborhood watch” for the GEO belt, providing space situational awareness to USSPACECOM. Built by…
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Geostationary orbit sits at about 35,786 km above the equator and completes a sidereal day (~23h56m), so satellites appear fixed over one longitude; Arthur C. Clarke popularized it in 1945, giving the region the nickname the Clarke Belt. A GEO satellite remains stationary relative to the ground, allowing ground antennas to point at a fixed…
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