It's tricky to pinpoint a single "invention" date for space satellites. The concept evolved over time with contributions from many people and organizations. Here's a breakdown:

Early Concepts:

* 1903: Konstantin Tsiolkovsky, a Russian scientist, publishes a paper outlining the concept of using rockets to reach space.

* 1920s: Hermann Oberth, a German scientist, publishes "The Rocket into Interplanetary Space," further developing rocket theory.

* 1940s: Wernher von Braun, a German rocket engineer, designs rockets for the Nazi regime, laying the groundwork for later space exploration.

First Satellites:

* 1957: The Soviet Union launches Sputnik 1, the first artificial satellite to orbit Earth, marking a pivotal moment in the space race.

* 1958: The United States launches Explorer 1, its first satellite.

Therefore, while Sputnik 1 is considered the first satellite launched, the concept of space satellites was developed over decades by various scientists and engineers.