Robert Mirelson said there was a full discussion by mid- and management-level engineers before the decision was made to send the new crew to the orbiting lab.
That decision was preceded by several pre-launch meetings in Moscow, Washington and the Johnson Space Center involving NASA engineers and experts from the International Space Station partner nations, he said.
The officials considered the concerns expressed by engineers about the air cleaning equipment, water supplies and the "quality of life equipment," which would include medical supplies, and concluded the launch would be safe.
The Washington Post reported Thursday, however, that two officials overseeing health and environmental conditions on the space station didn't sign off on the launch, instead signing a dissent that warned about "the continued degradation" of the environmental monitoring and health maintenance systems and exercise equipment vital to the astronauts' well being.
The Russian spacecraft filled in for the second time since the U.S. shuttle program was grounded this year after the Columbia disaster, delivering a three-man crew Monday to the International Space Station.
American Michael Foale, Russia's Alexander Kaleri and Spain's Pedro Duque entered the space station after the autopilot docking of their spacecraft, two days after the Soyuz blasted off from Kazakhstan. Duque is to remain aboard the station for eight days before returning to Earth with American Ed Lu and Russian Yuri Malenchenko, who have been aboard since April 28.
NASA Administrator Sean O'Keefe told the Post that, as he understood it, there was no immediate hazard to the crew but that conditions could deteriorate in the next six months and force the crew to abandon ship.
By Paul Recer