Earth observation satellite
Earth observation satellites or Earth remote sensing satellites are satellites specifically designed for Earth observation from orbit, similar to spy satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc. 
The first occurrence of satellite remote sensing can be dated to the launch of the first artificial satellite, Sputnik 1, by the Soviet Union on October 4, 1957. Sputnik 1 sent back radio signals, which scientists used to study the ionosphere.
NASA launched the first American satellite, Explorer 1, in January 31, 1958. The information sent back from its radiation detector led to the discovery of the Earth's Van Allen radiation belts.
The TIROS-1 spacecraft, launched on April 1, 1960 as part of NASA's TIROS (Television Infrared Observation Satellite) Program, sent back the first television footage of weather patterns to be taken from space.
, more than 150 Earth observation satellites were in orbit, recording data with both passive and active sensors and acquiring more than 10 terabits of data daily.
Fly Me to the Moon (film)
The narrator explains that in 1957, the Soviet Union launched Earth's first satellite Sputnik 1 into orbit. Four years later in 1961, when NASA was putting a monkey named Enos aboard Mercury Atlas 5, astronaut Yuri Gagarin became the first man on Earth to go to space. Feeling the sense of urgency to overtake the Soviets in the space race, U.S. President John F. Kennedy made a huge statement toward a joint session of Congress on May 25, 1961, stating that before the decade is out, he plans to launch a man to the Moon and return him safely to the Earth.