Considering the placement of your question in the category "jazz", it occurs to me you might be confused with Louis Armstrong, the Jazz trumpeter and singer.
If you mean Neil Armstrong, I quote from telegraph.co.uk:
"Though both of his parents were extremely devout, Neil Armstrong later professed no explicit religious beliefs. “They allowed me to pursue my own interests,” he said later. “They didn’t try to dictate to me what I should do or where I should go.”"
In case you mean Louis Armstrong, I quote from wikipedia:
"When asked about his religion, Armstrong would answer that he was raised a Baptist, always wore a Star of David, and was friends with the Pope. Armstrong wore the Star of David in honor of the Karnofsky family, who took him in as a child and lent him the money to buy his first cornet. Louis Armstrong was, in fact, baptized as a Catholic at the Sacred Heart of Jesus Church in New Orleans, and he met popes Pius XII and Paul VI, though there is no evidence that he considered himself Catholic. Armstrong seems to have been tolerant towards various religions, but also found humor in them."