Astronauts Pack Up Shuttle Cargo Pod, Inspect Heat Shield

Astronauts on NASA's space shuttle Discovery packed a cargo pod back inside their spacecraft's payload bay Friday and took one last look at their heat shield to look for any new damage.

The astronauts used the space station's robotic arm to return their bus-sized cargo pod Leonardo to Discovery's payload bay as they prepare to leave after more than a week at the orbiting lab.

The shiny cylindrical module delivered more than 8 tons of new supplies, science equipment and other cargo to the space station. It is now filled with trash and unneeded equipment to be returned back to Earth.

"We've got a lot of work accomplished up here and we still got a little more," Discovery astronaut Rick Mastracchio told Mission Control as the crew began their day. "We look forward to coming home soon."

The 21-foot-long Leonardo module was actually supposed to be moved back to Discovery Thursday night, but some technical glitches delayed that work much longer than planned. Discovery is due to undock from the space station Saturday at 8:52 a.m. EDT (1252 GMT).

Discovery's crew stayed up extra late to try and finish as much of the cargo pod move as possible after finally plucking it free Thursday. To make up for the long day, Mission Control let the astronauts sleep in Friday to rest up.

The Leonardo module, named after famed Renaissance artist and scientist Leonardo da Vinci, is making its last trip to Earth on this mission. When Discovery launches to the space station again, it will carry Leonardo to the station to serve as a permanent attachment to the orbiting lab.

After moving the Leonardo cargo module, Discovery's astronauts switched robotic arms. They used shuttle's 100-foot (30-meter) combo of its own robotic arm and sensor-tipped inspection pole to search for any signs of new damage to the heat shield panels along their wing edges and nose cap.

Known as a late inspection, the heat shield survey is a now-standard part every shuttle mission since the 2003 Columbia disaster to make sure a shuttle hasn't been damaged from micrometeorites or space debris.

The survey is usually performed after a space shuttle undocks, but Discovery's crew had the tricky task of inspecting their heat shield while still linked to the space station.

A main antenna failure on April 5, the day Discovery launched into space, forced the astronauts to scan their heat shield while at the space station in order to use the station's antenna to send the massive video files of the scan to Mission Control.

The astronauts had to take extra care to avoid bumping any part of the space station and had to work with some tight clearance issues. But despite those challenges, they actually were well ahead of their schedule during the inspection.

NASA engineers on Earth will review the video and data from the heat shield scan to make sure Discovery is safe to re-enter Earth's atmosphere. The shuttle's heat shield has already been cleared of any concerns related to launch debris.

Discovery is flying one of NASA's final shuttle missions before the space shuttle fleet is retired later this year. Only three more missions are left after this one, each one the last for the shuttle flying on it.

Discovery astronauts will have spent about nine days of their 14-day mission at the space station when they undock Saturday. They performed three spacewalks to make a tricky ammonia tank swap among other maintenance chores during that time.

The shuttle is due to land in Florida on Monday at 8:48 a.m. EDT (1248 GMT).

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