Live in orbit: Spacewalk Finally Under Way

U.S. astronaut Mike Fincke and Russian cosmonaut Yury Lonchakov are heading outside the International Space Station on a mission to set up and retrieve science experiments outside the outpost.

The spacewalk got under way at 7:51 p.m. -- 36 minutes later than schedule. Spacewalk preps were hampered by a sticky valve that slowed the depressurization of the Pirs airlock.

The spacewalk is the 119th performed in the assembly and maintenance of the station since its first two building blocks were linked in orbit 10 years ago this month.

The station was flying 220 miles above the planet when Fincke and Lonchakov exited the airlock. "Wow, this is beautiful," one of the two said.

"Going out into space again," said Fincke, who is making his fifth spacewalk. "Shall we go?"

"Yes," Lonchakov said.

You can follow the action here in The Flame Trench. Simply click the NASA TV box to launch our NASA TV viewer and live coverage. Refresh this page for periodic updates.

Check out the detailed timeline for the spacewalk here: Spacewalk Timeline.

The first order of business will be to mount a special probe on the outer hull of the airlock. The probe will measure the electromagnetic potential around the station.

Here's a graphic that shows where the probe will be mounted on the outside of the airlock:














And here is a close-up of the probe:

Bolts failures led to back-to-back ballistic reentries in October 2007 and April 2008 -- steeper than normal trajectories that subjected crews to forces eight or nine times greater than normal gravity.

The ballistic reentries also propelled both Soyuz craft and their returning crews to landings that were hundreds of miles off course.

The spacewalkers also will install two science experiments on a platform on the hull of the Russian Zvezda module, a command-and-control segment that doubles as crew quarters on the Russian side of the outpost.

Another suitcase-sized experiment packages will be retrieved for a return to Earth.

You can read more about the spacewalk and the objectives of the current tour of duty on the station here in this Expedition 18 Press Kit.

Click the hyperlink to download your own copy.

ABOUT THE IMAGE: Click to enlarge the NASA screen grab, which shows the Russian side of the International Space Station. On the far left of the view is the Russian Zvezda Module, a command-and-control module that also serves as crew quarters. To its right is a Progress cargo carrier and then a Soyuz spacecraft that doubles as an emergency lifeboard. It is moored to the Zarya module, a space tug that was the first element of the station launched in late 1998. It is connected to the U.S. Unity module, which serves as a gateway between the Russian side of the station and the rest of the outpost. The top two photos show Fincke on the outside of the Pirs airlock. He's floating upside down behind the Strela boom.