Live in Orbit: Spacewalkers Seek Expose-R

Spacewalkers Mike Fincke and Yury Lonchakov are about to "expose" themselves outside the International Space Station.

Not to the harsh environment of space, which could kill the American astronaut and Russian cosmonaut if a glove or other part of their Russian Orlan spacesuits tore during their nearly six-hour spacewalk.

Rather, the Expedition 18 teammates are beginning the day's key assignment, installing the European materials science experiment called Expose-R (shown at left) on the bottom of Russia's Zvezda service module.

Officially called "Exposing Specimens of Organic and Biological Materials to Open Space," the suitcase-sized experiment will test how materials including spores, microbes, bacteria and plant seeds react to the space environment over 14 months.

The experiments could help determine if life could have originated elsewhere before reaching Earth, according to the European Space Agency.

Fincke and Lonchakov tried to install the experiment last December, but an electrical cable problem prevented its activation and it was taken back inside for troubleshooting.

It's already been installed on a Zvezda bracket, but full installation should take another hour or so.

Check out this timeline to see a detailed list of the planned extravehicular activities.

The two spacewalkers completed their first task outside the International Space Station in less than an hour, using sharp cutters to trim six straps on the station's Pirs docking compartment.

The straps had been seen flapping around in an area near where Russian Soyuz and Progress vehicles dock. To make sure straps didn't cause any interference, managers decided to have them shortened 20 to 55 millimeters.

The spacewalkers also took a few photographs of the Russian segment of the Russian service module, called Zvesda, to check for any micrometeorite damage since the segment was launched in 2001. They'll take more later in the spacewalk, which is scheduled to last nearly six hours.

Fincke and Lonchakov today also checked out a cable related to a probe that was installed to monitor electrical potential around critical Russian systems, which is the suspected cause behind two consecutive ballistic Soyuz spacecraft re-entries in 2007 and 2008.

You can watch the entire spacewalk live by clicking on the NASA TV still image on the right side of the page to launch a NASA TV viewer. And refresh the page for updates throughout the spacewalk.

IMAGE NOTE: Michael Fincke and and cosmonaut Yury Lonchakov conduct a spacewalk outside the International Space Station. The space walk began at 12:22 p.m. EST, and is expected to last nearly six hours.