NASA officials have informed Discovery's six-member crew that the space shuttle is cleared for return home after engineers determined that its heat shield was free of damage, said reports from Houston, Texas on Sunday.

The ship's TPS (thermal protection system) is "100 percent clear for entry," Mission Control told Discovery Commander Steven Lindsey on Sunday, at the Johnson Space Center in Houston.

"That is great news, that's fantastic," Lindsey replied. "And to get all that done by the end of flight day six ... is just amazing."

Engineers examined a 2-inch-long (5-centimeter-long) piece of fabric gap filler sticking out from thermal tiles on Discovery's belly, which could have required a spacewalk for repairs.

They concluded that astronauts would not need to conduct a spacewalk to pluck the filler out, as it posed no threat for the shuttle's return to Earth.

The astronauts voiced their confidence earlier that the spaceship would be cleared to return.

Discovery will have a last checkup at the end of the mission to ensure its safe return to Earth, which is scheduled for July 17.

Source: Xinhua