CAPE CANAVERAL, Fla. (AP) - NASA was assessing a cracked thermal tile and protruding ceramic ring Wednesday on the space shuttle Endeavour - two new problems that don't appear serious but warrant extra attention.
"Initially, it doesn't look like we're going to be very concerned about them," said mission management team leader LeRoy Cain. "But we want to be very vigilant and take a closer look."
As engineers on the ground scrambled to understand the problems and determine whether repairs were needed, the 11 astronauts aboard the linked space shuttle and space station spent a relatively quiet first day together. They overcame a spacesuit problem in advance of Thursday night's spacewalk and replaced broken parts in a system that turns astronauts' urine into drinking water.
Shuttle astronaut Robert Behnken's spacesuit was unusable because of a faulty harness that prevented him from turning on his glove heaters and operating his helmet camera. So he borrowed the upper part of a suit already on the space station.
The most important job - installing a new room and an observation deck at the International Space Station - will get under way during Thursday night's spacewalk, the first of three.
As for the space station's water recycling system, the urine processor has been acting up for months. Endeavour took up replacement parts as well as a filter to catch all the calcium deposits in the urine. The repair work is such a high priority that it began within hours of the shuttle's arrival early Wednesday.
Astronauts can suffer considerable bone loss in weightlessness. It's conceivable excess calcium in their urine is clogging the machine, but officials believe the system itself is also to blame.
The unexpected shuttle problems grabbed management's attention Wednesday.
A thermal tile repair that was made before the flight has failed, and the original crack is back, right over the cockpit.
Then there's the round ceramic spacer near one of the cockpit windows that's sticking out. Engineers are trying to determine whether the spacer might come loose during re-entry and, if it did, whether it would slam into the rudder or orbital-maneuvering rockets.
Cain said it's too soon to know whether Behnken and his spacewalking partner, Nicholas Patrick, would need to attempt repairs. Another two to three days of analyses are needed.
NASA would prefer not sending astronauts out to work near the cockpit windows and other critical systems. They could inadvertently create a worse problem if they damaged the sensitive equipment, Cain said at a news conference.
"We have more questions than answers at this point," Cain said. "So we'll let the team go off and do the work."
NASA has been extra careful about such matters ever since Columbia was brought down by a cracked wing in 2003. The wing was smacked by a piece of fuel-tank foam insulation that broke off at liftoff, and the extent of the damage was not known until the shuttle broke apart during re-entry.
The good news Wednesday was that Endeavour's heat shield looks to be free of any major launch damage. All the pictures and data collected during the first three days of the flight came up empty.
By the time Endeavour leaves next week, the space station will be 98 percent complete. Four shuttle missions remain, essentially supply runs.
Astronaut Stephen Robinson was awe-struck when he drew close to the space station, during Endeavour's approach from below.
"To look up and see what humankind could really accomplish in space was just almost impossible to believe. It seemed like science fiction," he said. "Now here we are with human beings that are living on board. That truly is the amazing legacy of the space shuttle program."