The astronauts onboard the International Space Station started their first spacewalk, which was rescheduled for today at 9:35 a.m. EST, due to unidentified health issues with German astronaut Hans Schlegel. The spacewalk that was scheduled to take place on Sunday was postponed until today, when another astronaut, Stan Love, could replace him.

No specific details were given about the astronaut’s health problems. According to the NASA official web site, the delay will have no impact on the overall mission, and that the Atlantis is expected to return to the Kennedy Space Center in Florida on February 19 at 10:14 p.m.

Astronauts Rex Walheim and Stanley Love started their mission 22 minutes before the planned time, for their 7-hour work outside the International Space Station. You can follow their work live on NASA Tv. The work includes the attaching of a specially designed grapple fixture for the shuttle's robot arm to grasp.

"The grapple fixture is basically a big pin that the robot arm can grab onto and then pull the Columbus module out of the payload bay," Walheim told reporters before the shuttle flight, according to Reuters. "It could be launched with it on there. The only problem is it's a little bit too big to fit into the payload bay with the grapple fixture on."

In addition, the spacewalkers will detach nitrogen lines and otherwise begin work to remove the Nitrogen Tank Assembly, a part of the station’s thermal control system, from the P1 truss. The assembly needs to be replaced because the nitrogen is running low.

Schlegel and Pilot Alan Poindexter will coordinate the spacewalk activities from inside the orbiting complex, NASA announced. The first is allegedly recuperating fast and is doing "very well."

About 25 years in the making, Europe's Columbus space laboratory will finally be launched on a flight to the International Space Station on Thursday. The event occurs just 15 years late of its original launch date. The 17-nation European Space Agency developed the Columbus starting in 1982, aiming to launch it in 1992, to celebrate the 500th anniversary of the great navigator's voyage to the New World.

"Columbus means so much to Europe," said Alan Thirkettle, the European Space Agency's (Esa) space station programme manager, as quoted by BBC. "It means finally we will have our own real estate on-orbit - a multipurpose research laboratory that gives us the opportunity to do the world-class science we've been looking forward to for such a long time," he told BBC News.

The $2 billion lab will allow experiments to be conducted on the behavior of weightless liquids, and on micro-organisms, cells and tissues.

Columbus is designed for ten years of operation and will be controlled by the special Columbus Control Centre, located at the German Space Operations Centre, part of the German Aerospace Center (DLR). On May 27 last year, the Columbus lab was flown from Bremen to Kennedy Space Center on board an Airbus Beluga.