Coming up: Female commanders meet in space

Discovery's astronauts are closing in on the International Space Station, aiming for a historic link-up that will join the first two women to simultaneously serve as space mission commanders.

Look for veteran astronaut Pam Melroy, only the second woman to command a shuttle mission, to guide Discovery through a spectacular nose-over-tail backflip as the spaceship pulls within about 600 feet of the station.

The nine-minute maneuver -- which is scheduled to take place around 7:23 a.m. EDT -- will enable camera-wielding crewmates on the station to take high-resolution photos of the thousands of fragile heat-shield tiles on the underside of the orbiter.

The idea is to spot any damage that might have been done by external tank foam or ice debris during the shuttle's thundering ascent from Kennedy Space Center on Tuesday.

Live NASA TV coverage of the STS-120 shuttle mission is being webcast around the clock here in The Flame Trench , and you can watch the action unfold by clicking on the link below the image above. Doing so will launch our NASA TV viewer.

Discovery is scheduled to dock at the station at 8:33 a.m. EDT, and hatches between the spacecraft should swing open about an hour-later. Station skipper Peggy Whitson, the first female commander of the outpost, will stage a welcoming ceremony for Melroy and her crew around 10:33 a.m. EDT.

Meanwhile, ground engineers are analyzing launch video that showed a couple of foam pieces that might have struck the orbiter between 146 seconds and 156 seconds into flight -- just after the most critical period when debris can be propelled with enough kinetic energy to do damage to shuttle heat-shield components.

A small fabric "gap filler" was spotted jutting out from between tiles aft of a composite carbon panel near the outboard end of the shuttle's right wing during now-standard Flight Day 2 heat-shield inspections. And sensors within the starboard wing detected two potential debris hits that apparently struck with force not great enough to do critical damage.

The debris events do not appear to be serious.

The high-resolution photos taken during the shuttle's Rotational Pitch Maneuver will help determine whether the Discovery crew will be required to do a more focused inspection on Flight Day 5.

Also today: Shuttle mission specialist Dan Tani will become a member of the station crew after Discovery docks and his custom-made seat liner is installed in the Russian Soyuz lifeboat parked at the outpost.

NASA astronaut Clay Anderson, who has been living and working aboard the outpost since June, will become a member of the shuttle crew. He'll return to Earth aboard Discovery during an atmospheric reentry and landing set for Nov. 6.