The space agency says those with a B.A. in engineering, science or math and three years of relevant professional experience are required.
The application period is open through July 1, 2008.
The interview process is expected to last for six months before NASA announces its 2009 Astronaut Candidate Class.
Click here to apply online.
Additional information about the Astronaut Candidate Program is available by calling the Astronaut Selection Office at 281-483-5907.