U.S. NAVY NAVAL ASTRONAUT BADGE
As you might imagine, qualifying for the designation of Naval Astronaut is no small feat. To start, only officers are eligible for the designation, and then only if they have trained, achieved qualification, and been certified to pilot a powered craft that was designed to be flown at least 50 miles above the surface of the Earth. Then comes the most difficult part: actually completing a flight that meets those parameters.
The 50-mile limit was introduced in the 1960s, when the Department of Defense made the decision to award the Astronaut badge to any military personnel and civilians who had surpassed an altitude of 50 miles, replacing the previous standard of roughly 62 miles (100 kilometers). This change enabled many U.S. Air Force test pilots who had flown the experimental X-15 to earn the highly coveted badge, an honor they certainly deserved considering they were traveling at speeds over 4500 miles per hour.
All branches of the United States Armed Forces issue the Astronaut badge, and each iteration is based upon a winged aviation badge with a shooting star flying through a halo. Commercial astronaut badges are issued to members of crews of privately funded spacecraft; they too must surpass the 50-mile altitude mark to qualify. NASA, on the other hand, awards its Astronaut badge to any astronauts who have been selected for participation in the space program, regardless of whether or not they have even been in a vehicle capable of leaving the ground.