Roamy here. Some years ago, I read Mike Mullane’s autobiography Riding Rockets, and one incident that stood out was the difference between how the Navy and the Air Force treated their astronauts. I saw this article from military.com about astronaut Col. Doug Wheelock, and it got me thinking about how the astronaut corps is divided up between the services and civilians. I didn’t have the time to look at the entire history of the astronaut corps, but I did look through the active astronaut list from a dated Astronaut Fact Book and counted 41 civilians, 25 Navy and Naval Reserve, and 21 Air Force astronauts. I expected there to be more Marines, for some reason, but there were only 5 – Col. Charles Hobaugh, Lt. Col. Doug Hurley, Col. Frederick Sturckow, Col. Terrance Wilcutt, and Col. George Zamka.
The article mentioned five Army astronauts, who are Wheelock, Col. Timothy Creamer, Col. Patrick Forrester, Col. Tim Kopra, and Lt. Col. Shane Kimbrough. Two retired from the Army but still active in the astronaut corps are Col. William McArthur and Col. Jeffrey Williams.
And last but not least, the Coast Guard has only ever had two astronauts, Commander Bruce Melnick (now retired) and Captain Daniel Burbank.