At Heaven’s Gate: 50 Years After Humans First Reached Space, What Frontiers Remain? Scientific American

On April 12, 1961, Soviet cosmonaut Yuri Gagarin did something no human had done before. On board the Vostok 1 spacecraft, Gagarin became the first person in space after rocketing into the sky from a launch site in Kazakhstan for a nearly two-hour flight. What is more, Gagarin became the first human to orbit Earth, a feat that the U.S. would not achieve until its third manned spaceflight, John Glenn’s three-orbit flight on Friendship 7, February 20, 1962.
Fifty years later, both the space race—and the Cold War of which it was a part—have come to an end. The Soviet Union is no longer, but the Russian space program has become an invaluable partner to NASA’s human spaceflight program. Over the past decade more than a dozen countries, including Russia and the U.S., have sent astronauts to the International Space Station, the longest-serving continuously manned orbital outpost in history. Meanwhile, China has built up a formidable program of its own, sending three manned missions into space since 2003.
But human exploration of the solar system has contracted in scope since 1972, when the last set of Apollo astronauts to visit the moon returned to Earth. Whereas the first 10 years following Gagarin’s flight were peppered with firsts—notably the pioneering moon missions Apollo 8 and Apollo 11—the last four decades have witnessed little else but trips to and from low Earth orbit.
That ought to change, finally, in the decades to come. Space agencies around the world are planning ambitious missions to the moon and to even farther-flung locales that have never been visited by humankind. No one knows who the next Yuri Gagarin will be, or what flag will adorn his or her spacesuit, but below are a few solar system destinations that might find themselves festooned with fresh footprints in the next 50 years.