Space exploration is the activity of humans and other species traveling into the reaches of outer space. Initially, this was just gazing upward in wonder (see astronomy), but as scientific understanding of the solar system and universe developed, so did a desire to travel beyond Earth. This urge was first expressed in literature, then by rocket enthusiasts in many countries who formed societies to study the possibility of long-distance spaceflight. One of these groups, the Society for the Study of Interplanetary Travel (SSISP), produced liquid-propellant rockets that could reach orbital velocities.
Once such technology became available, the “space race” of the Cold War era pushed governments to develop programs for launching humans into space. For most of the 20th century, national government-sponsored space programs served a number of practical purposes: they increased knowledge, enhanced national prestige and power, and contributed to economic prosperity. Private companies also profited from activities in space, such as telecommunications relays.
Since then, humans have visited the Moon and lived for extended periods on orbiting space stations. Uncrewed spacecraft have landed on the Moon, Saturn’s moon Titan, Venus, Mars, and a few asteroids and comets. Some of these probes have even reached the inner Solar System, where they have gathered information about the heliosphere, a bubble around the Sun that contains solar wind particles.
The next major goal is the establishment of permanent bases on other celestial bodies such as the Moon, Mars and asteroids. This will provide a base for conducting unique and risky experiments, manufacturing equipment and providing access to the resources of these worlds. It will also allow scientists to understand the effects of long-term human living in space and test the viability of future interplanetary voyages.