Satellites

What was the first artificial Earth satellite?

There are about 2,000 active satellites orbiting earth right now.

In the context of spaceflight, a satellite is an object that [blank_start]has[blank_end] been intentionally placed into orbit. These objects are [blank_start]called[blank_end] artificial satellites to distinguish [blank_start]them[blank_end] from natural [blank_start]satellites[blank_end] such as Earth's Moon.

History The first published mathematical study of the possibility of [blank_start]an[blank_end] artificial satellite [blank_start]was[blank_end] Newton's cannonball, a thought experiment in A Treatise of the System of the World by Isaac Newton (1687). The first fictional depiction of a satellite being launched into orbit [blank_start]was[blank_end] a short story by Edward Everett Hale, The Brick Moon.[3][4] The idea surfaced again in Jules Verne's The Begum's Fortune (1879).

In May 1946, the United States Air Force's Project [blank_start]RAND[blank_end] released the Preliminary Design of an Experimental World-Circling [blank_start]Spaceship[blank_end], which stated that "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent [blank_start]scientific[blank_end] tools of the Twentieth Century."