"With that knowledge, technique, brains and physical strength, he is a superman in all respects," Koizumi told reporters.

"I wonder how they manage to do that," Koizumi said of the astronauts. "It is great for human beings to challenge the spirits.

"I want him to come back early and safely, but I know that he has a lot of work to do," he said.

Chief Cabinet Secretary Hiroyuki Hosoda, the government spokesman, said Koizumi was looking at how to speak with Noguchi while he is in space.

Noguchi, 40, blasted off with six other astronauts Tuesday on a 12-day mission that marks a resumption of US space flights nearly 30 months after the Columbia disaster in February 2003.

Japan's own space program followed a similar pattern this year. Japan successfully launched a satellite in February after a previous satellite had to be destroyed after liftoff in November 2003.

All rights reserved. copyright 2018 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.