In what might embarrass less adventurous souls, astronaut Koichi Wakata is returning to Earth with the underwear he kept on for a solid month during his space station stay and scientists will check them out.

They're experimental high-tech undies, designed in Japan to be odor free.

The Japanese spaceman described his underwear test Thursday as shuttle Endeavour and its crew aimed for a touchdown the next morning.

"I haven't talked about this underwear to my crew members," Wakata said in an interview with The Associated Press, drawing a big laugh from his six shuttle colleagues. "But I wore them for about a month, and my station crew members never complained for about a month, so I think the experiment went fine."

The Japanese underwear, called J-Wear, is a new type of anti-bacterial, water-absorbent, odor-eliminating clothing designed for space travel. The line includes shirts, pants and socks as well. Wakata tested all of them during his mission; he had four pairs of the silver-coated underwear, a cross between briefs and boxers.