Space exploration is a scientific field of study that involves the use of space technology to observe and understand the universe. It encompasses a wide range of disciplines, including Earth sciences, materials science, biology, medicine, and physics. Space exploration is the use of astronomy and space technology to explore outer space. Astronomers use telescopes to conduct space exploration, but physical exploration is also done with unmanned robotic probes and manned space flights.
Space exploration has been an important part of the space exploration programs of the Soviet Union (later Russia), the United States, Europe, Japan, and India. The physiological effects of spaceflight can be mitigated, but most space science is still conducted by robotic spacecraft in Earth orbit or on missions to various bodies in the solar system. The exploration of Mars has been a major focus of space exploration programs. The first remote celestial object to be flown over, orbited, and landed on by spacecraft was Mars.
It has also been visited by humans. The motion of a spacecraft in space is studied in astrodynamics. Some spacecraft remain in space indefinitely, some disintegrate during re-entry into the atmosphere, and others reach planetary or lunar surfaces to land or impact. The first era of space exploration was driven by a “space race” between the Soviet Union and the United States.
The launch of Sputnik 1 by the USSR in 1957 and the landing of Apollo 11 by the US on the Moon in 1969 are considered milestones of this period. The first scientific discovery made with instruments that orbit in space was the existence of the Van Allen radiation belts, discovered by Explorer 1 in 1958. Saturn has only been explored through unmanned spacecraft launched by NASA, including a mission (Cassini-Huygens) planned and executed in collaboration with other space agencies. Space exploration has become increasingly accessible to private interests in recent years. Private companies have begun to promote space tourism and private exploration of the Moon (see Google Lunar X Prize).
