Shuttle will carry high-tech repair kits

Extra tools in the toolbox
Discovery is also expected to carry some additional tools for other repair techniques, even if they’re left stowed during the flight.

“It’s like having an ejection seat in a jet,” Robinson said of the tools and techniques that aren’t planned for testing during STS-114 spacewalks. “You don’t plan to use it, but it’s not a bad idea to have it along.”

Among other tools may be an array of overlay panels made of a material called carbon silicon carbide that can be affixed over damaged shuttle tiles with screws.

NASA engineer Kevin Wells, extravehicular activity tools project leader for overlay repair, told Space.com that while it is relatively easy to install screws in shuttle tiles — they can be twisted using just a finger — astronauts would have to use special tool to measure torque to ensure the screw does not strip away needed material.

A second set of patches, made of material similar to the overlays but a bit sterner, may also fly during Discovery’s mission. The patches are designed to fit over a hole in a shuttle RCC panel, though researchers are still conducting ground tests to make sure hot gases don’t burn away or seep through patch edges.

“The gap [between patch and panel] is the predominant path for failure,” said Frank Lin, NASA’s project manager for RCC repair. “We could seal that gap with the NOAX material.”

NASA During a zero-gravity flight, astronaut Soichi Noguchi tests an applicator gun designed to inject fast-curing patch material into a gap in the shuttle's thermal protection system.

One last and potentially problematic repair method includes filling severely damaged tiles with a pink, ablative goolike substance called STA-54, which is squirted into place from a backpack-mounted tank. The goo is actually made of two separate materials that are mixed together as they pass through a handheld device. STA-54 is designed to rise like bread as it heats up during re-entry, with the outer surface ablating away and new material swelling up to take its place, NASA engineers said.

Tests in vacuum chambers and during zero-gravity flights aboard NASA’s KC-135 aircraft have found that the STA-54 material is prone to bubbling as it cures, which could diminish its effectiveness if left unresolved.

Discovery’s new reach
The largest addition to Discovery’s toolbox is a 50-foot (15-meter) boom that can be attached to end of the orbiter’s robotic arm in orbit, nearly doubling its length.

A suite of sensors, including cameras and a laser ranging system, should sit on the end of the boom and allow the Discovery crew to scan the orbiter’s underbelly for cracked or broken tiles and other damage. Should that senor package fail, a platform can be attached to the boom’s end in order for an astronaut to make a visual inspection and take digital images.

“We do have to be prepared for the possible failure of the sensor package,” Noguchi said.

Even without the orbital boom and sensor package attached, Discovery’s robotic arm has an additional role for its first return-to-flight mission.

NASA engineers said STS-114 astronauts have been training to perform a maneuver that relies solely on the robotic arm, in which the manipulator will latch onto the international space station and turn the shuttle until its tiled belly is in position for observation or repair.

“I don’t think that we’re going too fast,” Robinson said of Discovery’s timeline and NASA’s push to resume shuttle flights. “The amount of questions remaining is still very small.”

MORE FROM SPACE

Space Section Front

Trio brings holiday cheer to space station Rover makes discovery while spinning wheels Cosmic Log: The year in space   2009's best images from space How much real science is in ‘Avatar’? Mystery swirls around ‘dark stars’ Cassini image confirms liquid on Saturn moon Long-defunct Mars rover wheel spins Crew blasts off for Christmas space mission Earth's upper atmosphere cooling dramatically Space Section Front   Add Space headlines to your news reader: