Since ancient times, human beings have looked up into the night sky and wondered what was beyond it. Space exploration aims to answer that question, and more. It involves developing and using spacecraft to reach outer space and explore planets, their moons, asteroids, comets, other solar systems and the universe beyond. It also involves building and operating space stations, which enable scientific research in an environment that is different from Earth.
Early in the 20th century, national governments began funding space programs. These programs helped make it possible to send satellites into orbit and land humans on the Moon. They also made it feasible to build and operate a large space station, which is used for long-term living and exploration.
Currently, the focus is on space science, joint human and robotic missions to near-Earth asteroids, Mars and destinations beyond our Solar System. Human space flight is a difficult endeavor, and the challenge of making it safe and successful encourages innovation and the development of important skills. It also demonstrates that humanity is capable of pushing its boundaries and striving for greater achievements.
The design of space capsules and stations needs to consider how people will live in them. Space explorers need enough room to work and sleep, as well as food, water, clothing, and equipment. There must be facilities to recycle water and produce fuel, and space vehicles require protection from the cold of space and harmful radiation. Temperature control is also a consideration, from the cold of night on the Moon and Mars to the high daytime temperatures of space stations.