In this image taken from video provided by NASA TV, international space station astronaut Peggy Whitson, the station's first female commander, speaks to ground controllers on her 48th birthday Saturday aboard the space station. Atlantis maneuvered toward a rendezvous with the international space station Saturday, bringing a new billion lab that European scientists can't wait to see installed.

Cape Canaveral, Fla. ? Space shuttle Atlantis and its astronauts delivered a sparkling new lab to the international space station Saturday, but had to delay installing it by a day because of a crew member’s medical problem.

One of the two spacewalking astronauts who was to help install the $2 billion European science lab, Columbus, was pulled from the job because of a nonlife-threatening condition.

The installation won’t take place now until Monday.

NASA officials would not say why German astronaut Hans Schlegel was being replaced, but Atlantis’ commander, Stephen Frick, requested a private medical conference with flight surgeons shortly after reaching the space station.

“I will just say it’s not going to impact any of the objectives of this mission,” said John Shannon, chairman of the mission management team. “It will cause us to rearrange a few activities.”

Shannon refused to elaborate, citing medical privacy. When asked by another reporter if it was contagious, he said: “You guys can fish all day, but I won’t bite.”

Schlegel, 56, a two-time space flier, did not appear to be sick when he floated inside the space station and took part in a safety briefing, but he seemed quiet. He was seen on camera for only several minutes.

Schlegel was supposed to venture outside with American Rex Walheim on the first two of three planned spacewalks. His status on the second spacewalk, on Wednesday, was still uncertain.

The Columbus lab should have been unloaded from Atlantis and attached to the space station today, with two spacewalkers outside to help. Mission Control informed the astronauts about the delay just a few hours after the shuttle and the station joined up.

NASA said Schlegel’s shuttle crewmate, American Stanley Love, would take his place. Love trained for the work as a backup, just in case, and already was assigned to the mission’s third spacewalk, along with Walheim.