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 non-life-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, 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 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 on Sunday, 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.
It was a rare and unsettling change in plans for NASA, which typically prepares for every aspect of a shuttle mission — particularly spacewalks — for months and even years.
The last time a shuttle astronaut's health drastically affected flight operations was in 1990; Atlantis' commander caught a cold, and the launch had to be delayed. And in 1982, an astronaut's space motion sickness — a common affliction — delayed the first shuttle spacewalk, which ultimately was canceled because of suit problems.
The delay in installing Columbus and carrying out the first spacewalk 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. Atlantis will remain at the orbiting complex until at least next weekend.
NASA, meanwhile, was analyzing a small tear in one of Atlantis' thermal blankets.
Before pulling up to the space station, Atlantis did a 360-degree backflip so the crew aboard the complex could photograph the shuttle's thermal shielding. Nearly 300 photos were beamed back to Earth so engineers could look for any signs of launch damage.
Mission Control requested extra pictures of the torn thermal blanket on Atlantis' right orbital maneuvering system pod, back near the tail. The small tear, along a seam, occurred during Thursday's launch and was discovered Friday, said flight director Mike Sarafin.
Engineers were trying to ascertain whether the tear posed a hazard for re-entry at flight's end. The exact size of the peeled-up section was unknown, but it appeared to be smaller and less worrisome than one that required spacewalking repairs last June. Coincidentally, that tear was in a blanket on Atlantis' left orbital maneuvering system pod.
"It's probably not that big of an issue, but we're off looking at it," Sarafin said.
The photos of the shuttle's thermal shielding tiles are standard procedure, ever since the destruction of Columbia in 2003. Columbia's wing was gashed at liftoff by a chunk of fuel-tank insulating foam. Only a small amount of foam is believed to have come off Atlantis' tank, and none of it appeared to seriously damage the shuttle.
Space station astronaut Daniel Tani, in orbit for nearly four months, wasted no time swapping places with newly arrived Frenchman Leopold Eyharts. The two formally exchanged spacecraft seats late Saturday, a day early. Tani will return to Earth aboard the shuttle, leaving Eyharts behind.
As for the Columbus lab, its delayed installation was just another bump in the road for the European Space Agency.
The original plan called for Columbus to be launched in 1992 to mark the 500th anniversary of Christopher Columbus' voyage to the New World. But years passed as NASA redesigned the space station. Then station construction ended up being stalled, and then the shuttle fleet was grounded for 2 1/2 years following the Columbia tragedy.
