Are there any atheist or agnostic American astronauts, past or present?
With the hundreds of astronauts who have been through the American space program, I am sure there are more than a few atheists and agnostics, but they're likely quiet about it. The only publicly self-identified atheist astronaut I know of is not American, ESA's Christer Fuglesang.
Can't answer the overall question, but for Group 1 specifically, there's a discussion of the recruitment program here. The original plan was to recruit twelve, to allow for some dropping out during the program. When it became clear there were unlikely to be many dropouts, they revised the target to six. However, when making the final selection, they got ...
I googled it for you.
NASA astronaut requirements
have changed with NASA's goals and missions. A
pilot's license and engineering experience is still one route a person
could take to becoming an astronaut, but it’s no longer the only one.
Today, to be considered for an astronaut position, U.S. citizens must
meet the following qualifications:
It's hard to get a comprehensive statistic of all astronauts, but 1 in 4 of the early US astronauts (Mercury- Apollo) were left handed, including the following:
I can't find a reliable statistic beyond the Apollo era, but I suspect that percentage has gone down. Also note that ...
Based on the excellent answer by @TokyK let's look at the numbers with python:
even_odd = [[(i/2**n)%2 for n in range(12)] for i in range(2**12)]
sums = [sum(x) for x in even_odd]
A, B = np.histogram(sums, bins = range(14))
[1, 12, 66, 220, 495, 792, 924, 792, 495, 220, 66, 12, 1]
4096. / (1 + 12 + 66 + 66 + 12 + 1)
It's not that much of a coincidence -- about 1 in 52 for 10 or more odd numbers out of 12. You would have been just as surprised by ten or more even numbers, so you can bring that down to 1 in 26. And you would have been just as surprised to see such a discrepancy in the Soviet space program, instead of the US program, so you can bring it down to 1 in 13.
From here (images too sloppy to copy text from)
The link has some statistical results.
A more recent (1985) description can be found on pages 23-25 of this paper; again, the text is not readily copy-able. It does say, in reference to the Mercury tests
The 15 tests used for astronaut selection primarily examined
the neuropsychological and ...