However, NASA is not ready to say for sure whether the object is projected to collide with the shuttle and station, though the paths were likely to cross on Tuesday, said deputy manager of the space shuttle program LeRoy Cain.
"What we were told today is very preliminary," Cain said yesterday. "It is a potential right now".
Cain said he was unaware what size the object may be, but expected more information later Sunday or Monday.
Tuesday is the scheduled day for a spacewalk by two US astronauts aboard the ISS as part of Expedition 28.
On June 28, a piece of space debris narrowly missed the ISS in a rare incident that forced the six-member crew to scramble to their rescue craft, space agency officials said.
The high-speed object hurtled toward the orbiting lab and likely missed it by just 1,100 feet (335 meters). The crew moved to shelter inside two Soyuz spacecraft 18 minutes before the debris was expected to pass, NASA said.
"It was probably the closest object that has actually come by the space station,"NASA`s associate administrator for space operations, Bill Gerstenmaier, said afterward.
"We didn`t have any information that it was coming until it was very, very close."
The size of the space junk remains unknown and no harm was done by its fly-by.