During the second spacewalk Walheim and Schlegel removed an empty Nitrogen Tank Assembly (NTA). With the help of astronauts inside the space station, who were operating the robotic arm, they also moved a new, full NTA from the shuttle Atlantis’ payload bay and into the cleared position of the old NTA.

The new NTA unit will help cool the station. The installation took place on the P1 truss of the space station.

The old NTA will be returned to Earth inside the cargo hold of the space shuttle.

The spacewalking astronauts also installed thermal covers on the trunnion pins on the ESA Columbus scientific laboratory. With plenty of time left in their spacewalk, the astronauts also inspected the debris shields on the U.S. Destiny laboratory module. They help to deflect micrometeroids out in space near the station.

During the second spacewalk, the German control center for Columbus swapped out the primary software for the backup software. They found that the primary softwar had some bad data, which prevented the German controllers from communcating with their new Columbus module. The swap worked, and the control center was communicating with Columbus by the time the second spacewalk was finished.

On Friday, February 15, 2008, Stanley Love, who substituted for Schelegel on the first spacewalk, will join Walheim on the third spacewalk. It begins at approximately 8:35 a.m. EDT.

Coverage of it will be on NASA TV.

During their excursion outside of the space station the two space workers will install two payloads to the outside of the Columbus laboratory.

The first one, Solar Monitoring Observatory (SOLAR/SMO), is an ESA science observatory that will monitor the Sun.

It consists of three instruments: SOVIM (SOlar Variations and Irradiance Monitor), SOLSPEC (SOLar SPECtral irradiance measurements), and SOL-ACES (SOLar-Auto-Calibrating Extreme ultraviolet and ultraviolet Spectrometers).

The three instruments will provide measurements of the spectral irradiance of the Sun at various wavelengths of the electromagnetic spectrum.

They will operate for an expected lifetime of 1.5 years.

The second payload to be install outside of Columbus, the European Technology Exposure Facility (EuTEF), consists of eight experiments that use the vacuum of space to complete their assigned tasks.

The mission management team for STS-122, headquarterd at the Johnson Space Center, in Houston, Texas, also announced to the STS-122 crew that their mission has been extended to February 20, in order to perform more work on Columbus.

The crew found out that Atlantis has a good thermal protection system, and management team for the mission cleared the shuttle and crew for a return to Earth.

They will undock from the ISS on Monday, February 18, with an expected landing at the Kennedy Space Center at about 9:06 a.m. EDT Wednesday, February 20, 2008.

The third spacewalk, on Friday, will be televised live on NASA TV.

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