Project Mercury was announced in 1958, but 50 years ago this month the astronauts were selected and presented to the public. I found two different selection dates — April 1st, according to this NASA page about the 40th anniversary, and April 2nd, according to this NASA list of anniversaries.*
(NASA publicity photo of the Mercury Seven)
All sources agree that the “Mercury Seven” astronauts were announced at a NASA press conference on April 9, 1959. They were Scott Carpenter, L. Gordon Cooper, Jr., John H. Glenn, Jr., Virgil I. “Gus” Grissom, Walter M. Schirra, Jr., Alan B. Shepard, Jr., and Donald K. “Deke” Slayton.
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*From which I get the space anniversaries I want to highlight here on the blog.
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For the record, I have always admired Deke Slayton most of that original 7. He was a classy guy and set multiple space records himself. I’m sure you know these but I’ll list them anyway: only member of the 7 NOT to fly on Mercury or Gemini missions, the only Marine of the 7, set the record for oldest man in space when he flew on the Apollo-Soyuz mission in the mid-70s. One regret in life is not being able to meet him before he died in ’94 from brain cancer. I have a feeling I’ll see him again. 😉