A spacecraft is a vehicle designed to travel through space beyond Earth's atmosphere. Unlike airplanes, which need air to fly, spacecraft work in the vacuum of space where there's no air at all. They carry everything they need with them: fuel, oxygen for astronauts, and systems to survive extreme temperatures and radiation.

Spacecraft come in many forms. Some, like the Space Shuttle or SpaceX's Dragon capsule, carry people and supplies to space stations orbiting Earth. Others are robotic probes sent to explore distant planets: the Voyager spacecraft have been traveling for over 45 years and are now in interstellar space, beyond the region dominated by our Sun's solar wind. Satellites orbiting Earth are spacecraft too, helping us communicate, navigate, and study weather patterns.

The first spacecraft, Sputnik 1, launched in 1957 and changed humanity forever by proving we could build machines that work beyond our planet. Today, spacecraft explore Mars, study the Sun, photograph distant galaxies, and might one day carry humans to other worlds. Every spacecraft represents thousands of people solving incredibly difficult engineering problems to push the boundaries of what's possible.