History of the day (April-25th)
On April 25th 1990, Hubble Space Telescope was deployed in Space in a low orbit around Earth.
An LEO (low Earth orbit) is an orbit used by an orbiting object and that is close to Earth. Most of the artificial objects like the ISS (International Space Station) are deployed in the LEO.
A low Earth orbit requires the lowest amount of energy for satellite placement. It provides high bandwidth and low communication latency. Satellites and space stations in LEO are more accessible for crew and servicing. (Source Wikipedia)
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