Since ancient times, humans have looked up into the night sky and wondered about the nature of objects they saw. With the development of long-distance rockets in the 20th century, it became possible to send machines and animals and later people above Earth’s atmosphere and into outer space.
Scientists and engineers have been exploring the Solar System and other parts of the Universe with space probes, orbiters, rovers, lander missions, satellites, and telescopes. New discoveries are being made all the time! For example, recent work with the Kepler and Gaia space telescopes has widened our view of planets beyond our own, giving scientists even more reason to think that life could exist elsewhere in our Universe.
For decades, national pride and competition with the Soviet Union and other world powers played an important role in motivating space programs. Many of the major world powers launched manned spaceflights to claim prestige and demonstrate technological power. The US and Soviet programs culminated in the Apollo 11 landing on the Moon, a milestone that gave both countries reason to be proud.
Today, space exploration is a worldwide endeavor with nations cooperating on the International Space Station and other planetary missions. Private companies are also developing space transportation systems with the potential to open up a new avenue of human spaceflight, including trips to near-Earth asteroids and Mars. The establishment of permanent bases on the Moon, Mars, or other planets will require space stations and colonies with living quarters, research laboratories, factories, observatories, and facilities to produce food, water, and fuel.