Live In Orbit: Construction Site With A View

Spacewalking astronauts Steve Swanson and Joe Acaba are breezing through assembly work at the International Space Station, and the view from the orbital construction site is unrivaled.

With Discovery docked to the U.S. side of the outpost, the joined shuttle-station complex is whizzing around Earth at 17,500 mph -- Mach 25 -- or 25 times the speed of sound.

The station is flying high above the planet -- about 220 miles -- and it circles the planet 16 times a day, or once every 90 minutes. The joined crews of Discovery and the station have an opportunity to see an orbital sunrise or sunset once every 45 minutes.

You can click to enlarge these NASA TV screen grabs. Both show the view from outside the station as the complex soars over the North Atlantic.

Swanson and Acaba are just about mid-way through a planned 6.5-hour spacewalk -- the 122nd performed in the operation and maintenance of the station since its first two building blocks were linked in low Earth orbit in late 1998.

Crewmates inside the station have installed a new distillation assembly in a U.S. urine processing system and are conducting a dry run. The system, which is designed to convert urine to potable drinking water, was delivered to the station late last year, but its original distillation assembly did not work properly. NASA astronaut Sandra Magnus installed a unit flown up on Discovery and so far, the dry run is proceeding without problems.

You can watch the action unfold right here in The Flame Trench. Simply click the NASA TV box on the righthand side of this page to launch our NASA TV viewer and live coverage of the second of three spacewalks planned during Discovery's stay at the station.

And be sure to refresh this page for periodic updates.