One of the crew members, European Space Agency astronaut Thomas Reiter, stayed behind on the ISS for a planned 145-day mission.
The rest of the astronauts landed in the shuttle, guided by commander Steven Lindsey, to hoots and whistles from the few hundred relatives of the crew and space center workers gathered at the runway.
“It was a great mission, a really great mission, and enjoyed the entry and the landing,” Lindsey said.
NASA officials were certain going into Monday’s landing that Discovery’s heat shield was intact and capable of protecting the spacecraft during re-entry. The orbiter was repeatedly inspected in space, but NASA officials acknowledged that re-entry, along with the launch, are the most dangerous phase of the mission.
Discovery’s crew and flight controllers kept a close eye on a slightly leaking power unit, but the leak was small and the unit operated properly, reported the Associated Press.
During the mission, which began on July 4, the astronauts conducted three space walks, one of them to test shuttle patching techniques.
A 100-foot inspection crane, used to check the shuttle’s heat shield from damage during launch, also was utilized as a work platform for spacewalkers.
The crew also delivered several thousand pounds of supplies to the space station.
In addition, the astronauts fixed a broken rail car on the outside of the space station, paving the way for ISS construction to begin again in earnest with the next shuttle launch.
NASA is planning to launch Atlantis as early as Aug. 27 to bring a building-block beam to the space station.
The ISS is half finished eight years after construction began. NASA hopes to have it complete by 2010 — the target year for the space shuttles to retire to make way for a different type of crew vehicle to carry astronauts to the moon.