Commander Eileen Collins said astronauts on shuttle Discovery had seen widespread environmental destruction on Earth and warned yesterday that greater care was needed to protect natural resources.

"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," Comm. 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 Comm. Collins, who was standing with Japanese astronaut Soichi Noguchi in front of a Japanese flag and holding a colourful fan.

Comm. Collins, flying her fourth shuttle mission, 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."

Nasa yesterday cleared lingering concerns about shuttle Discovery's condition to return home and told the crew to pack up their spacesuits because there was no need for a fourth spacewalk.

"We have good news," astronaut Julie Payette, speaking from Nasa's Mission Control, radioed to the crew. "The MMT (mission management team) just got to the conclusion that the blanket underneath the commander's window is safe for return. There is no issue. So basically, no EVA four," she said referring to Nasa's acronym for extravehicular activity or spacewalk.

Engineers had been studying whether a piece of damaged cloth insulation beneath the commander's left cockpit window could break off as the shuttle flew in for landing and damage a part of the shuttle critical for flight, such as the tail or a movable body flap.