NASA's shuttle Discovery is closing in on the International Space Station and due to arrive later today, its crew of seven astronauts eager to deliver new solar wings for the orbiting lab's power grid.
Shuttle commander Lee Archambault is slated to dock his 100-ton spacecraft at the station at 5:13 p.m. EDT (2113 GMT) today after a two-day orbital chase. After months of isolation 220 miles (354 km) above Earth, the space station's three-person crew is more than ready to see some new faces.
"The crew is 100 million percent ready," station commander Michael Fincke radioed down to Mission Control late Monday. "Tomorrow is game day."
Discovery launched toward the space station late Sunday on a 13-day mission to deliver new solar arrays and swap out one member of the station's Expedition 18 crew. Three spacewalks, cut down from four due to launch delays, are planned for the mission.
In addition to the new $298 million solar wings, which will complete the station's U.S.-built power grid once installed, Discovery is ferrying Japanese astronaut Koichi Wakata to the station to replace NASA astronaut Sandra Magnus as an Expedition 18 flight engineer. Magnus will return home aboard Discovery next week, while Wakata - Japan's first long-duration astronaut - is due to return home this summer on a later shuttle flight.
Mission Control roused Discovery's crew this morning with the traditional Japanese song "Radio Exercise" by the Tokyo Broadcast Children's Choir, a tune selected especially for Wakata.
"It's another wonderful morning in orbit," Wakata said. "I'm looking forward to going into our new base in space later today."
Discovery is also toting a middeck crammed with extra supplies for the space station, including a spare part for the outpost's broken recycling system that filters astronaut urine back into drinking water. The part, a distillation assembly, will be installed while Discovery is docked at the station and its broken counterpart will be returned to Earth for analysis, mission managers said.
"I'm looking forward to a very nominal rendezvous," shuttle flight director Paul Dye said late Monday. Today's planned docking is unaffected by a piece of space debris that passed by the station early this morning, he added.
NASA engineers initially thought they might have to fire the station's thrusters to avoid the debris, a bit of trash from a defunct Soviet navigation satellite - but later found that the object posed no threat and would fly well clear of the orbital outpost. No engine burn or other precautions were required, Dye said.
Before Discovery's crew can get to work at the space station, Archambault will guide the spacecraft through a slow back flip below the orbiting lab so astronauts inside can take photographs of the shuttle's tile-covered belly.
"We'll basically flip the space shuttle Discovery," said in pilot Dominic "Tony" Antonelli in a NASA interview.
Called the Rendezvous Pitch Maneuver, Discovery's orbital flip is part of the now-standard heat shield inspection plan NASA has used since the 2003 loss of shuttle Columbia and its seven-astronaut crew during re-enter due to wing damage.
During the shuttle somersault, Archambault will fly the spacecraft to a point about 600 feet (183 meters) directly below the space station. While Discovery turns in a controlled end-over-end spin, station astronauts will take about 300 high-resolution photographs of the thousands of heat-resistant tiles lining the spacecraft's belly.
Engineers on Earth will study the images to search for any dinged or damage tiles that might need repair.
The survey adds to a Monday inspection of the heat shield panels along Discovery's wing edges and nose cap by the shuttle astronauts. After combining the data and images from both surveys, engineers will decide whether Discovery's crew will have to perform an extra focused inspection of any specific areas of the heat shield later in the mission.
LeRoy Cain, head of Discovery's mission management team, said late Monday that shuttle managers hope to decide whether the extra inspection will be required by late Wednesday.
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