Discovery, making its way to the international space station, is carrying the orbiting outpost's biggest room by far - Japan's $1 billion lab. The shuttle is also delivering a spare pump for the space station's malfunctioning toilet.
But the inspection of the shuttle was not as thorough as it normally is because the school-bus-size lab, named Kibo - Japanese for hope - takes up almost the entire payload bay.
That left no room for a 50-foot laser-tipped boom that is attached to the shuttle's 50-foot robotic arm.
Usually on a shuttle's second day in space, astronauts use the boom and robotic arm to conduct a meticulous, slow-motion inspection of the spacecraft's wings and nose - the shuttle's most vulnerable areas - for any signs of launch damage. It's become a routine safety procedure ever since the 2003 Columbia accident.
Without the boom, Discovery's robotic arm was only able to do a partial survey of the thermal protection system, limited to looking at the shuttle's wings. The inspection began early Sunday afternoon and lasted less than two hours. Engineers on the ground were set to review the data.
A more thorough inspection was planned at the halfway point as well as near the end of the 14-day mission after Discovery's crew retrieves a laser-tipped boom left behind at the space station by Endeavour's astronauts when they visited the orbiting outpost in March.
Bill Gerstenmaier, NASA's space operations chief, said the limited inspection combined with photographs taken of Discovery just before it docks with the space station on Monday should give agency officials good data to determine if anything happened to the spacecraft during launch.
"We've got a very solid plan for this," he said.
About five pieces of debris - what appeared to be thin pieces of insulating foam - broke off the fuel tank during liftoff on Saturday.
But the losses did not occur during the crucial first two minutes and should be of no concern, Gerstenmaier said. This was the first tank to have all safety changes prompted by the 2003 Columbia disaster built in from the start.
Discovery's U.S.-Japanese crew planned to conduct three spacewalks to install Kibo, replace an empty nitrogen-gas tank and try out various cleaning methods on a clogged solar-wing rotating joint.
Kibo is 37 feet long and weighs more than 32,000 pounds. The first part of the lab flew up in March, and the third and final section will be launched next year. Kibo will bring the orbiting outpost to three-quarters of completion.
During the mission, the space station's two Russian residents will put in the new toilet pump.
The outpost's three residents have had to manually flush the toilet with extra water several times a day, a time-consuming, water-wasting job.
One of Discovery's astronauts, Gregory Chamitoff, will move into the space station for a six-month stay. He'll replace Garrett Reisman, who will return to Earth aboard the shuttle.
