Astronauts on the US space shuttle Endeavour on Tuesday finished routine inspection of the thermal protection system on the orbiter's wing leading edges and nose, NASA said.
The crew soared into orbit Monday carrying an observation deck for the International Space Station, a seven-windowed dome offering breathtaking views.
On much of their first day working in space, Commander George Zamka, Pilot Terry Virts and Mission Specialists Kay Hire, Stephen Robinson, Nicholas Patrick and Robert Behnken inspected heat-resistant tiles and reinforced carbon-carbon surfaces on those high friction areas.
"Zamka, Hire and Patrick used the shuttle?s arm and its Orbital Boom Sensor System extension to survey Endeavour?s right wing. Subsequently, Virts and Robinson joined the commander for the nose cap survey. Hire replaced Zamka for the port wing survey," NASA said.
The crew was looking for any sign of being hit by ice, and for foam insulation damage that in the past has plagued the external fuel tank. Images were beamed back to mission control in Houston, Texas, to be analyzed.
Some small bits of foam did break off two minutes after launch but apparently without harming the shuttle, Bill Gerstenmaeir, who is in charge of NASA space operations, said late Monday.
In addition to the heat tile inspection, which took about seven hours, the shuttle crew readied for its rendezvous with the ISS. Docking is scheduled for just after midnight 0506 GMT Wednesday.
Astronauts who started their day around 0900 Tuesday (1400 GMT) will be awakened at 2214 GMT to start approach preparations ahead of docking with the ISS.
The Endeavour mission's main goal is to deliver the massive Tranquility module, also known as Node 3, which comes with a multi-window cupola attached.
Built for NASA by the European group Thales Alenia Space in their Turin factory, the cupola will provide unparalleled panoramic views of Earth and space.
Six windows arrayed along its sides and another on top -- all protected against the impact of tiny meteorites -- will provide an unprecedented, wide-ranging view for those onboard and help crew members monitor spacewalks and docking operations.
The cupola can accommodate two crew members at a time, and is equipped with portable workstations that can control station and robotic activities.
Installing the Tranquility module amounts to a major construction job, requiring a team of two astronauts to undertake three spacewalks lasting 6.5 hours each, the National Aeronautics and Space Administration said.
Once the room is in place, the space station will be 90 percent complete.
The module, named after the lunar sea where Apollo 11 landed, has the most sophisticated life support system ever flown into space -- air revitalization, oxygen generation and water recycling systems, as well as a waste and hygiene compartment for the crew.
The mission, one of five scheduled for NASA's three shuttles before the program ends later this year after a 29-year run, comes as the US space agency reevaluates its future after President Barack Obama effectively abandoned its plan to send astronauts back to the moon by 2020.
The Constellation program was intended to develop a successor spacecraft to the shuttle, which could carry astronauts to the moon. They could then use a lunar base to launch manned missions to Mars.
Constrained by soaring deficits, Obama submitted a budget to Congress that encourages NASA to focus instead on developing commercial transport alternatives to ferry astronauts to the ISS after the shuttle program ends.
The ISS, a joint project involving 16 countries, has cost around 100 billion dollars, mostly funded by the United States.
Under Obama's new budget, the floating research station could see its life extended by five years until 2020.
