A satellite is any object that orbits a planet, star, or moon. Earth and the Moon are natural satellites. Thousands of artificial satellites orbit Earth
As of December 2024, 83 GPS satellites have been built. 30 satellites are operational, 1 undergoing commissioning. 3 Block III satellites completed and AFL, next launch planned for 2025. Constellation requires minimum 24 operational satellites, up to 32
Geostationary satellites orbit 35,785 km above equator, appearing stationary. Medium Earth orbit satellites (MEO) operate 2,000-36,000 km above equator. Low Earth orbit satellites (LEO) operate 160-2,000 km above equator
First satellite dish was Taylor Howard's military dish in 1976. Early dishes were 20 feet in diameter for C-band analog reception. Wire mesh dishes reduced from 10 to 4 feet by 1990s. Ku band allowed first reliable 90 cm dishes in 1988. EchoStar introduced 51 cm dishes in 1996
Geomagnetic storms are temporary disturbances of Earth's magnetosphere caused by solar wind shock waves. Solar coronal mass ejections (CMEs) or co-rotating interaction regions drive storms. Solar wind pressure initially compresses magnetosphere, transferring energy to Earth's field
First space images taken by US V-2 in 1946 at 65 miles altitude. First orbital Earth photos by US Explorer 6 in 1959. Landsat program launched in 1972, largest Earth imaging program. First real-time satellite imagery by KH-11 in 1977