NASA’s Hyperion, launched in 2000 on the EO-1 satellite, collected 220 spectral bands from 400 to 2500 nm at 30 m resolution. A hyperspectral data cube stacks hundreds of narrow wavelength bands for every ground pixel, creating a two-dimensional spatial image plus a spectral dimension. Hyperspectral imaging records hundreds of narrow bands (often 10 nm…
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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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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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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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In 2022, Apple’s iPhone 14 introduced Emergency SOS via satellite, later expanded in the iPhone 15 to support satellite texting via Globalstar. In April 2023, AST SpaceMobile’s BlueWalker 3 demonstrated a two-way 4G call using a standard smartphone on Earth with a 64 m² satellite antenna. Lynk Global demonstrated the first direct satellite text to…
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By 2024, small satellites accounted for over 95% of all satellites launched annually. SpaceX’s Starlink operates the world’s largest constellation with over 7,000 active satellites in orbit as of late 2024. Starlink’s initial shell consisted of about 4,400 satellites at roughly 550 km altitude and 53° inclination, with FCC approval for about 12,000 satellites and…
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The United States operates the Advanced Extremely High Frequency (AEHF) constellation, delivering jam-resistant, global, protected military communications including nuclear command and control links. Navstar GPS is a 31-satellite global navigation system that provides precise positioning, navigation, and timing to guide munitions such as JDAM and to synchronize encrypted networks. Defense Support Program (DSP) and the…
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By late 2022, more than 10,000 aircraft worldwide were equipped with in-flight connectivity, and about 65% of airlines planned further IFC investments in the next few years. Aireon’s space-based ADS-B payloads on Iridium NEXT have been operational since 2019, enabling global real-time tracking and supporting ICAO’s 15-minute GADSS position reporting standard. COSPAS-SARSAT, a global satellite…
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Iridium operates 66 active LEO satellites in a cross-linked constellation, providing truly global coverage including the poles. Inmarsat uses 3–4 GEO satellites at about 36,000 km altitude to cover most of the globe from roughly 70°N to 70°S, and its IsatPhone 2 offers 8 hours of talk time. Globalstar runs about 48 LEO satellites to…
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LEO satellites orbit at roughly 500–1,200 km, delivering latency of about 20–50 ms and broadband speeds comparable to terrestrial networks, versus GEO’s ~600 ms latency. SpaceX Starlink has launched over 7,000 satellites since 2019, provides coverage in about 130 countries, had more than 4 million subscribers by late 2024, and offers 50–200 Mbps to rural…
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