Space exploration is the investigation of the cosmos beyond the upper regions of the Earth's atmosphere using telescopes, satellites, space probes, spacecraft, and associated launch vehicles.

Background

The desire to explore space is nearly primal for Homo sapiens. Early humans quickly spread out of Africa to every region on the planet, then came to speculate that the stars and planets were yet other material places worthy of exploration. The idea to travel to these other worlds was inevitable.

However for thousands of years, humans commonly drew fundamental distinctions between the Earth and non-Earth environments. In the formulation of Aristotle taught that the laws of nature that applied on Earth did not necessarily apply beyond the Earth, thus severely restricting the very possibilities for human space exploration.

During the great age of European exploration of the Earth, astronomers such as Galileo Galilei (1564–1642) and his contemporary, Johannes Kepler...