The idea of space exploration has captured the imaginations of humans since we first looked up at the night sky. With the development of rockets and other technologies in the 20th century, it became possible to send machines, and then animals, and finally humans beyond Earth’s atmosphere for scientific study and to explore other worlds.
The Soviet Union launched the first artificial satellite, Sputnik, on October 4, 1957. The United States made several attempts to launch a satellite before success with Explorer on January 31, 1958. This satellite measured cosmic rays and other particles that reach Earth’s atmosphere and proved the existence of the Van Allen radiation belts around our planet.
Other probes have been sent into Earth orbit and to the Moon, Mars, and Jupiter’s moons. In 1969 on Apollo 11, the U.S. astronauts landed on the Moon, collecting samples that still help scientists learn about that world.
In addition to its direct benefits for the science of astronomy, space exploration has also led to many technology spinoffs. These include the Global Positioning System (GPS) that uses satellites to give us accurate location information down to 1m on Earth, and environmental control systems for spacecraft that can withstand the harsh environment of space.
Looking to the future, NASA and other agencies hope to create a permanent lunar outpost, send astronauts to Mars, explore the outer planets of our Solar System, and look for life near and far away from home. But all of this requires money. Some people wonder whether the resources invested in space exploration could be better spent on other things, such as helping to alleviate poverty or assisting the transition to renewable energy worldwide.