 In February 1999, Furukawa was selected by the National Space Development Agency of Japan (NASDA) as one of three Japanese astronaut candidates for the International Space Station (ISS).He started the ISS Astronaut Basic Training program in April 1999 and was certified as an astronaut in January 2001.Since April 2001, he has been participating in ISS Advanced Training, as well as supporting the development of the hardware and operation of the Japanese ISS Experimental Module “Kibo.”

On October 1, 2003, NASDA merged with ISAS (Institute of Space and Astronautical Science) and NAL (National Aerospace Laboratory of Japan) and was renamed JAXA (Japan Aerospace Exploration Agency).