They keep a secret of their beliefs. They swear an oath to that. Why high ranking people go to it if it is not giv8ng them power in some way?
It's another group that people can join, in order to meet other people who might be able to help them climb the corporate/social ladder.
In one organisation I worked for it was supposedly fairly common knowledge that the workforce contained large groups of Catholics and Masons. The theory was that Masons would do everything they could to help fellow Masons get promoted, and the Catholics would do everything they could to help fellow Catholics get promoted. Naturally, if people were promoted ahead of others with supposedly better skills, then it's reasonable to believe that promoted Masons were promoted at the expense of non-Masons, including Catholics. And vice versa.
Whether the astronauts were able to pull similar stunts I don't know.
Just another thing, LionKing: look at the first day cover again and see the dates he reached his "Degrees": 1955 and 1956 - not only before he was an astronaut but before the first satellite was launched. In other words, Aldrin wasn't a "high-ranking" person at the time. People didn't join the Masons because they
already were high-ranking; they joined it when they were low-ranking in the hope it would help them
become high-ranking.