This spring marked the 55th anniversary of the dawn of the space race, when Russian cosmonaut Yuri Gagarin became the first human to orbit the Earth in April 1961. While the Soviet Union’s accomplishment spurred the United States to put a man on the moon before the 1960s came to a close, space exploration has since become a more internationally collaborative affair.
Related: International Space Station Crew Returns Home Today. See Photos of Their Year in Space
New achievements in space travel are happening all over the world, like India's successful test launch of the country's first reusable space shuttle. Another recent major milestone occurred this spring when NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko made history, returning safely home following their stint as the International Space Station’s first "One Year Crew."
What the scientific community learns from Kornienko and Kelly's experience will be invaluable to the astronauts who will be sent on a mission to Mars in the 2030s. Read on to glance back on some historic anniversaries and look ahead to what's on the horizon for space exploration.