Space travel

Space travel is nothing like in the movies. Getting from A to B requires complex calculations involving inertia and gravity—literally, rocket science—to "slingshot" from planet to planet (or moon) across the solar system. The Voyager mission of the 1970s took advantage of a rare alignment of Jupiter, Saturn, Uranus, and Neptune to shave off nearly 20 years of travel time. Space is also dangerous. More than 20 astronauts have died doing their job.

That hasn’t stopped people from signing up and blasting off. NASA’s shuttle program has ended, but private companies are readying their own space programs. A company called Planetary Resources plans to send robot astronauts to the Asteroid Belt to mine for precious metals. Another company named SpaceX is hoping to land civilian astronauts on Mars—the next human step into the solar system—in 20 years. NASA and other civilian companies are planning their own Mars missions. Maybe you’ll be a member of one? Don’t forget to bring your dog.

Our first steps into space began as a race between the United States and the former Soviet Union, rivals in a global struggle for power. Laika was followed into orbit four years later by the first human, Soviet Cosmonaut Yuri A. Gagarin. With Earth orbit achieved, we turned our sights on the moon. The United States landed two astronauts on its stark surface in 1969, and five more manned missions followed. The U.S.’s National Aeronautics and Space Administration (NASA) launched probes to study the solar system. Manned space stations began glittering in the sky. NASA developed reusable spacecraft—space shuttle orbiters—to ferry astronauts and satellites to orbit. Space-travel technology had advanced light-years in just three decades. Gagarin had to parachute from his spaceship after reentry from orbit. The space shuttle leaves orbit at 16,465 miles an hour (26,498 kilometers an hour) and glides to a stop on a runway without using an engine.