After all, shooting people off our planet in giant combustible devices is one of humanity's greatest ongoing endeavors, and deserves its own cozy spot on the calendar.

To that point, it's astonishing to reflect on how much has been achieved in human spaceflight since Gagarin's first foray in orbit with the iconic Vostok spacecraft. In just over a half-century, humans have left footprints on the Moon, performed dozens of spacewalks and thousands of experiments, and constructed two continuously inhabited space stations in low Earth orbit. 

On top of that, this year's International Day of Human Spaceflight coincides with the delivery of the Bigelow Expandable Activity Module (BEAM) to the International Space Station (ISS).