. "Donald Roy Pettit (born April 20, 1955) is an American chemical engineer and a NASA astronaut. He is a veteran of two long-duration stays aboard the International Space Station, one space shuttle mission and a six-week expedition to find meteorites in Antarctica."@en . . . . "3.1968e+07"^^ . . . "1955-04-20Z"^^ . "Pettit, Donald"@en . "American astronaut" . . "1955Z"^^ .