Around 560 people have been to space, which may sound like a lot, but actually it's about the number of people who could fit on a very large passenger airplane.
Humans have been going to space since Yuri Gagarin flew in orbit around the Earth in 1961. But the rocket launches since then have been infrequent. Only 12 of NASA's astronauts walked on the moon during the Apollo-era of the late 1960s and early 1970s. And the space shuttle flew just 135 times during its 30-year career, or an average of almost five times a year.
But now there are a few companies trying to open up space to ordinary people, maybe one day even to kids. Two of them - Virgin Galactic and Blue Origin - want to take tourists on trips to the edge of space. These people wouldn't orbit the Earth, but rather they would fly up and then come back down.
But they would get far enough away from the Earth's surface to break the bonds of gravity and experience weightlessness. For a few minutes, passengers would be able to unbuckle their seat belts and float around the spacecraft's cabin, and even perform somersaults.
Outside their window, they would have an amazing view. They would see the curvature of the Earth. They would also see the thin line of the atmosphere, the layer of gases that surrounds the planet and absorbs harmful radiation from the sun, allowing life on Earth to exist.
And even if it were in the middle of the day, the sky beyond would be dark.
Elon Musk, SpaceX's chief executive, said recently that he would fly a Japanese billionaire named Yusaku Maezawa on a trip around the moon. Maezawa wants to invite several artists, including sculptors, painters, architects and film directors, to come with him and hopes the trip would help their work "inspire the dreamer in all of us."
Flying to space is very expensive. Virgin Galactic charges $250,000 (R3,5 million) a ticket. For that much money, you could buy a house in some places. Getting to space is also dangerous. In 2014, one of Virgin Galactic's test pilots died when the spacecraft he was flying suddenly came apart mid-flight. The company said it has fixed the problem and has resumed its test program.
By next year, all three companies hope to fly people to space. It promises to be an exciting adventure, full of risk and thrills.
Would you go?