It was the second highest number of applications ever received for astronaut training, a NASA release said.
"The Flight Crew Operations Directorate is very happy with the large number of applicants for the astronaut program," said Janet Kavandi, director of Flight Crew Operations. "NASA feels strongly that an appropriate mix of skills, education and background provide the office with a greater ability to successfully work a wide array of operational situations."
Successful candidates will live and work aboard the International Space Station and help build the Orion spacecraft for exploration beyond low earth orbit.
"Historically, we've received between 2,500 and 3,500 applications for each class," Duane Ross, who heads NASA's Astronaut Selection Office, said. "We were a bit surprised, but very pleased by the overwhelming response to our recent Astronaut Candidate vacancy announcement."
"To me, this demonstrates the fact that the public remains genuinely interested in continuing the exploration of space."
The Astronaut Selection Board is expected to make its final decision in the spring of 2013 with the new astronaut candidates reporting for two years of training that summer.