Space shuttle Atlantis and its astronauts delivered a sparkling new lab to the international space station Saturday, but they 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. The installation won't take place 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, but noted that it was not a life-threatening condition. 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 a few minutes.
At one point, space station astronaut Daniel Tani is heard asking someone, "What did you do to your voice?"
NASA's public affairs office refused to speculate whether the question was directed to Schlegel. But it would be a safety issue if a spacewalker could not speak.
Schlegel was supposed to venture outside with American Rex Walheim on the first two space walks. His status on the second space walk, 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 space shuttle and the station joined up.
NASA said Schlegel's 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 space walk, along with Walheim.
It was a rare and unsettling change in plans for NASA, which typically prepares for every aspect of a shuttle mission - particularly space walks - for months and even years.
The delay in installing Columbus and carrying out the first space walk prompted NASA to add a 12th day to the mission. Yet another day could be added; NASA had hoped to spend an extra day at the space station to help set up Columbus.
The two spacecraft linked up as they passed more than 200 miles above Australia. Just over an hour later, the seven shuttle astronauts and three station residents threw open the hatches, laughing and shouting.