Why is the MTV Music Award an astronaut?

Because the most ubiquitous bumper video logo shown on MTV in its early years featured footage of the first rocket to the moon, and the first man walking on the moon with the (American) flag. It was Xeroxed and rotoscoped, then hand-colored with markers. Instead of the American flag, the flag had the MTV logo on it, flashing in different colors and patterns. This image became iconic and representative of MTV as a brand. The MTV trademark music riff (complete with guitar wow) is as iconic and well-known as the moon landing image to the first viewers of MTV.