Discovery spent two weeks in space, where the crew demonstrated new methods to inspect and repair the Shuttle in orbit. The crew also delivered supplies, outfitted and performed maintenance on the International Space Station. A number of these tasks were conducted during three spacewalks.

In an unprecedented event, spacewalkers were called upon to remove protruding gap fillers from the heat shield on Discovery's underbelly. In other spacewalk activities, astronauts installed an external platform onto the Station’s Quest Airlock and replaced one of the orbital outpost’s Control Moment Gyroscopes.

Inside the Station, the STS-114 crew conducted joint operations with the Expedition 11 crew. They unloaded fresh supplies from the Shuttle and the Raffaello Multi-Purpose Logistics Module. Before Discovery undocked, the crews filled Raffeallo with unneeded items and returned to Shuttle payload bay.

Shortly after Discovery lifted off July 26, a 1-pound chunk of foam insulation fell from the fuel tank — the very thing that doomed Columbia. The foam missed Discovery, but NASA grounded all shuttle flights until engineers fix the problem.

"We're going to try as hard as we can to get back in space this year," NASA Administrator Michael Griffin said at a post-landing news conference. "But we’re not going to go until we're ready to go."

The final issue of concern -- a torn thermal blanket just below the cockpit window that might shed bits of debris during the shuttle's descent -- was cleared off the table Thursday morning after a series of wind-tunnel tests, said deputy shuttle program manager Wayne Hale, who heads Discovery's mission management team.

The tests indicated that even if pieces of cloth debris blew off and struck the aft section of the orbiter, it would be "of negligible concern" and pose no threat to Discovery's safe landing, he said. Under those circumstances, sending spacewalkers out to snip away the torn section would have violated the "first, do no harm" rule, Hale said.

"Neither of us saw anything really alarming," station astronaut John Phillips told NASA mission control.

Until the foam issue can be fixed, shuttles will not lift-off, Nasa says.

Tuesday's shedding foam is not thought to have hit Discovery, but two heatshield tiles do appear to be broken underneath the vehicle.

However, the first reports of the ISS investigation indicated there were no major areas of damage to contend with.

It was a suitcase-sized piece of foam that fell off the Columbia shuttle during its launch and punched a hole in the wing.

Solid Rocket Booster separation was triggered 2-minutes and 5-seconds into the flight after burnout of the putty-like fuel packed inside each rocket. The firing of explosive bolts freed the twin boosters from the side of the External Tank, allowing them to peel away from the Space Shuttle. Parachutes were then automatically deployed from the boosters, allowing them to slowly descend into the Atlantic Ocean where they will be towed back to shore.