Washington, July 30 (Xinhua) Astronauts inspected the space shuttle Endeavour's heat shield one more time with lasersand cameras before their scheduled landing on earth Friday, NASA has said.

Endeavour's thermal protection system was cleared for landing earlier in the flight. This late inspection will ensure that there has been no damage from micrometeoroids or space junk during its docked operations or fly-around of the International Space Station (ISS), NASA said Wednesday.

A preliminary look at the images beamed down found nothing amiss, and everything was on track for Friday's planned landing, the US space agency said.

It added that there are two landing opportunities at NASA's Kennedy Space Centre in Florida at 1448 GMT and 1623 GMT Friday.

NASA will evaluate weather conditions at Kennedy before permitting Endeavour and its crew to land.