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.
Humankind has landed and walked there before—six times, in fact—but since 1972 the only lunar visitors have been of the robotic variety. The U.S. remains the only nation to send its astronauts to the moon, and for several years it looked as if NASA would be back before anyone else. President George W. Bush proposed in 2004 that NASA return humans to the moon by 2020, but the feasibility of that goal was already waning when President Barack Obama scuttled the moon shot in 2010. Obama chose to scrap the Bush-era moon goal and the spacecraft system that was to enable it in favor of a more flexible strategy toward space exploration using a new deep-space launcher, whose specifics have become a point of contention between NASA and Congress.
Meanwhile, China has been ramping up its lunar exploration program, sending unmanned orbiters to the moon in 2007 and 2010. China has also demonstrated the ability to send its space flyers, sometimes known as taikonauts, into orbit—and officials have said that taikonauts could set foot on the moon by 2025. That timeline seems to mesh with the other leading contender for a lunar return. Along with China and the U.S., Russia is the only nation with a proved ability to send humans into space. The head of the Russian space agency has said that cosmonauts would land on the moon by 2025.
But, as with the plans for a Chinese moon mission—and as NASA is well aware following its abandoned Bush-era plans—many technical challenges stand between the decision to go to the moon and planting a flag on the lunar surface. It remains to be seen which nations, if any, are willing to pursue the expensive, complicated and dangerous goal of a manned moon landing.
When Obama steered NASA away from the moon, he directed the space agency toward a manned asteroid landing around 2025 instead. The attractions of such a mission are myriad: For starters, no nation has ever achieved it nor has any nation's astronauts ventured so deep into the solar system. And asteroids are a rich library of scientific information, preserving a record of the chemical conditions that prevailed when the solar system was in its infancy. An asteroid visit might also afford a significant logistical advantage over a moon landing: The much weaker gravitational pull of an asteroid means that a spacecraft could simply rendezvous with it at close range so astronauts could spacewalk to the surface without the need for a full-fledged landing module.
But nothing in space travel is easy, and touching down on an asteroid might be a sight more complicated than a simple rendezvous. Asteroids are often odd-shaped bodies that spin extremely rapidly. Some are little more than rubble piles, and their loose structure combined with weak gravity means that the vicinity of an asteroid might be littered with loosely bound debris.
In any event, such a mission would require NASA to develop a heavy-lift launch system to spring a crew of astronauts out of Earth orbit, and the specs, timeline and cost of such rockets have caused friction between the space agency and Congressional funders.