HOUSTON - NASA managers for the International Space Station (ISS) have formally asked for an extra day of docked operations with the STS-114 astronauts aboard Discovery, shuttle officials said Friday.

NASA space shuttle program deputy manager Wayne Hale, who chairs Discovery's Mission Management Team (MMT), said ISS officials requested the one-day mission extension to allow more time for transfer of material between the orbiter and the ISS.

That material, he said, consists of additional items to the 15 tons of supplies Discovery ferried to the ISS.

The MMT will meet Saturday to discuss adding the extra day, but will likely opt to go along with the plan.

"I expect that's what we'll do," Hale said.

Earlier today, STS-114 mission operations representative Phil Engelauf said an engineering team is compiling a list of items Discovery's crew could pluck from their orbiter and leave at the ISS as a precaution against an extended delay between Discovery's space station visit and the next shuttle's arrival. Among the possible items that could be pinned for transfer are laptop computers, unique space tools or extra water produced by Discovery's fuel cells, he added.

The Atlantis orbiter is next in line to launch toward the ISS - with an initial flight window opening in September - but will likely not fly until NASA address a still unresolved foam debris issue that became abundantly clear during Discovery's Tuesday launch.

During the July 26 space shot, an external tank-mounted video camera caught a large chunk of foam insulation separated from the tank just over two minutes into the flight, but did not impact Discovery. Additional image analysis turned up several smaller foam pieces that also popped free, one of which may have contacted the orbiter - inspections and impact sensors detected nothing - though it would have hit with 1/10 the energy needed to pose a hazard, Hale said Thursday.

ISS officials are also discussing the possibility of tacking on an additional task to the third spacewalk planned for Discovery's crew.

STS-114 spacewalkers Soichi Noguchi and Stephen Robinson will make their first venture outside Discovery early Saturday to test new orbiter repair techniques and replace a space station global position system antenna. A second spacewalk is set for Aug. 1, with the final EVA slated for Aug. 3.

It is for that Aug. 3 spacewalk that ISS managers are considering whether to ask Noguchi and Robinson to retrieve a motor from a thermal radiator on the station's exterior, though a formal request has not yet been made, Hale said.

"That is a potential task to be added," Hale said, adding that engineers are hoping to perform a failure analysis on the motor.

Mind the gap filler

Video and still photography taken of Discovery's belly-mounted heat-resistant tiles have given shuttle engineers their first look of an established phenomena seen in past shuttle flights.

The imagery caught two ceramic gap fillers, typically wedged between tiles that are spaced too far apart, poking about an inch out into space. While not due to damage, the gap filler images are the first views taken of the phenomena in orbit. Engineers typically don't find protruding gap fillers until orbiters land back on Earth.

"This is really kind of exciting data," Hale said, adding that other gap filler protrusions are behind Discovery's nose landing gear doors, where such protrusions have occurred in the past. "There appears to be something going on behind the nose landing gear door that we'll look at."

Protruding gap fillers disrupt the aerodynamic flow around shuttles during descent, which can cause higher than normal heating aft of the protrusion, Hale said.

Engineers are discussing whether any measures are needed to address the gap fillers or other incidents, such as a damaged thermal blanket that was found during inspections.

"All of these things are not serious in the sense that they don't cause serious alarm," Hale said.

Analysts have also pinned down the size of a chipped tile near the nose landing gear doors after STS-114 astronauts observed it with Discovery's sensor-tipped orbital boom.

The damaged area is about three inches wide, 3/4^ths of an inch long and about 1/3^rd of an inch deep, but does not breach any thermal protective barriers.

"That is very good news," Hale said. "I'm feeling very confident that this is not going to turn out to be anything very significant."

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