Commander Eileen Collins said astronauts on shuttle Discovery had seen widespread environmental destruction on Earth and warned today that greater care was needed to protect natural resources.
Her comments came as NASA pondered whether to send astronauts out on an extra spacewalk to repair additional heat-protection damage on the first shuttle mission since the 2003 Columbia disaster.
Discovery is linked with the International Space Station and orbiting 220 miles (352 km) above the Earth.
"Sometimes you can see how there is erosion, and you can see how there is deforestation. It's very widespread in some parts of the world," Ms Collins said in a conversation from space with Japanese officials in Tokyo, including Prime Minister Junichiro Koizumi.
"We would like to see, from the astronauts' point of view, people take good care of the Earth and replace the resources that have been used," said Ms Collins, who was standing with Japanese astronaut Soichi Noguchi in front of a Japanese flag and holding a colorful fan.
Ms Collins, making her fourth shuttle flight, said the view from space made clear that Earth's atmosphere must be protected, too.
"The atmosphere almost looks like an eggshell on an egg, it's so very thin," she said. "We know that we don't have much air, we need to protect what we have."
While Ms Collins and Mr Noguchi chatted, NASA officials were deciding whether a rip in an insulation blanket that protects part of the shuttle surface could tear off and strike the spacecraft when Discovery re-enters the atmosphere, possibly causing damage.
Deputy shuttle program manager Wayne Hale said NASA's concern stemmed from an abundance of caution since Columbia.
"I think in the old days we would not have worried about this so much," he said in a briefing.
The agency was to decide later today whether to order a spacewalk to repair the blanket. The spacewalk would take place on Saturday if needed.
Mr Noguchi and astronaut Steve Robinson already have done three spacewalks, including a landmark walk yesterday to remove loose cloth strips protruding from Discovery's belly. NASA feared the strips could cause dangerous heat damage when the shuttle lands on Monday.
After Discovery comes home, there may not be a shuttle mission for a while because NASA has suspended flights until it figures out how to stop insulation foam from the spacecraft's external fuel tank from coming loose at launch.