The European Columbus laboratory has been successfully attached to the Harmony module on the International Space Station at 22:44 CET on Monday, after a seven-hour, 58-minute spacewalk by Mission Specialists Rex Walheim and Stanley Love, who were responsible for bolting the Power and Data Grapple Fixture (PDGF) to the Columbus module.

European Space Agency astronaut Leopold Eyharts announced the Mission Control centers in U.S. and Germany that “The European Columbus module is now part of the International Space Station.” The official activation of the Columbus module is expected to take place Tuesday, February 12, when Leopold Eyharts will be the first to enter the Columbus laboratory.

“Another great day for the European Space Agency,” said Alana Thirkettle, ISS Program Manager for the European Space Agency, on the agency’s official Web site. “Now we have four of the international partners with their elements on the Station. It is really becoming the International Space Station. We are very much looking forward to having the fifth partner joining us next month,” he added.

The first spacewalk was initially scheduled to take place on Sunday, but health problems of German astronaut Hans Schlegel delayed it by 24 hours. Officials avoided giving specific details on the astronaut’s health problems, simply saying his condition will improve. NASA said postponing the date will not interfere with the overall mission, and so far, it appears it hasn’t.

A second spacewalk has been scheduled for Wednesday at 9:35 a.m., when Mission Specialists Rex Walheim and Hans Schlegel will be responsible for completing the replacement of the nitrogen tank and installing trunnion covers on the Columbus module. With so many unfortunate incidents so far, hopefully nothing else will go wrong.

The Columbus laboratory, which is a 23 feet long, 15 feet wide, 12.8 tons module, will enable scientists aboard the International Space Station and researchers at the ground to conduct experiments in conditions impossible to recreate on Earth. The Columbus Control Center, located in the German Space Agency facility in Oberpfaffenhofen, will be responsible for monitoring and providing communication links with control centers from Russia and the United States.