Live In Orbit: Crew Sets Stage For 3rd Spacewalk

Crane operating astronauts put in place an experiment-laden carrier outside the International Space Station today, setting the stage for the third of five spacewalks planned during shuttle Endeavour's stay at the outpost.

Astronauts wielding both station and shuttle robot arms installed the 1.2-ton carrier on a porch outside the Japanese Kibo science research facility after a carefully choreographed orbital hand-off.

Endeavour mission specialist Julie Payette of the Canadian Space Agency and mission commander Mark Polansky used the station's Canadian-built robot arm to hoist the carrier from the shuttle's expansive cargo bay.

Then they handed it off to crewmates Koichi Wakata and Douglas Hurley, who were operating the shuttle's robot arm. Wakata and Hurley maneuvered the carrier into position on the porch.

The installation cleared the way for Chris Cassidy to prep three science experiments on the carrier to be put in place outside the Kibo lab. Wakata and station flight engineer Tim Kopra will use Kibo's robotic arm to do that work Thursday.

The experiment packages include an x-ray observatory that will scan the entire sky every 90 minutes with two different detectors. The detectors will observe x-ray emissions from high-energy celestial objects radiating hot gas at extremely high temperatures.

Among them: galaxy clusters, black holes, supernova remnants, stars, and binary stars and neutron stars. Some interplanetary bodies in the solar system also emit x-rays, most notably, the moon, which reflects solar x-rays from the sun.

A second experiment package will measure the environment around the space station, gauging levels of plasma, heavy ions, high-energy light particles, atomic oxygen, and cosmic dust in the outpost's orbit. That experiment also will help researchers determine how the environment affects materials and electronic devices.

The third experiment package will map stratospheric trace gases using an extremely sensitive submillimeter receiver. The instrument will measure ozone-depleting chlorine, hydrochloric acid, molecular hydrogen and bromide, among other constituents.

The carrier will be moved back to the shuttle's cargo bay and returned to Earth.

Coming up: the astronauts will snatch another shuttle-launched carrier from the station's mobile rail cart and then position it for the shuttle crew's third spacewalk on Wednesday. The carrier holds six new station batteries that will be installed on the far port end of the outpost's central truss by spacewalkers Dave Wolf and Chris Cassidy.

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ABOUT THE IMAGES: Click to enlarge the NASA TV screen grabs that show the shuttle-launched experiment carrier being put in place outside the Japanese Kibo science research facility at the International Space Station.