News reports last month said some NASA experts have warned that environmental monitoring and health maintenance systems on the station had deteriorated to the point that it was unsafe for astronauts. NASA has been under the microscope since the Feb. 1 shuttle Columbia accident that killed the seven astronauts on board. Investigators blamed the disaster on lax safety procedures at the U.S. space agency.
Before Foale and Kaleri were sent up in a Russian Soyuz capsule on Oct. 18 for a 200-day stay, NASA officials said the station, which just marked its third year of continuous occupation, was in good enough shape.

At a news conference from the station on Oct. 23, Foale told reporters he had been warned about the safety objections but thought it was safe on the station.

NASA and its station partners in Russia, Europe, Japan and Canada opened the $95 billion orbiting laboratory to long-duration crews in 2000 hoping it would mark a permanent human presence beyond Earth.