Shuttle Discovery Gears Up for Return to Flight

CAPE CANAVERAL -- NASA engineers here are ramping up efforts toreturn the space shuttle Discovery to flight status, the agency's first mannedspacecraft set to fly since the loss of the shuttle Columbia and its crew.

Slated for launch sometime between March 6 to April 18 in2005, Discovery's STS-114 mission is expected to test out in-flight shuttlerepair techniques, as well as new sensors and a camera to keep ground crewsapprised of the spacecraft's health. The mission will also deliver supplies andmuch needed equipment to the International Space Station (ISS).

"I feel very comfortable that we can make aMarch launch right now," said Stephanie Stilson, NASA's Discovery vehicle manager,during a July 23 press tour at Kennedy Space Center (KSC). "We've gotten overthe hump."

Stilson said Discovery's return-to-flight modificationsshould be complete in the next few months, with rollout currently scheduled forearly January.

Adherence to that schedule is critical not only for theresumption of NASA's manned space program, but also for the future of the ISSin order to complete its core construction by the end of the decade.

PreppingDiscovery

Among the more extensive changes to Discovery aretemperature and impact sensors being built into both of the shuttle's wingleading edges. Wiring for the new equipment has already been installed insideeach wing, with sensor relays and data storage boxes to follow.

"Monitoring the wing is critical for return to flight," saidShaun Green, NASA's senior instrumentation engineer at KSC.

Damage to the Columbia's left wing, caused by falling foamfrom the shuttle's external tank during liftoff, is believed to have led to itsdestruction during its reentry.

Green said the new sensors will be able to take 20,000 samplesper second as Discovery rockets into space, and are should function in orbit todetect micrometeorite impacts. Each wing will carry 22 temperature sensors and66 accelerometers designed to monitor any impacts when the modifications arecomplete. Data will be relayed to ground control in Houston via a laptopconnection in the orbiter's crew compartment.

A new digital camera will snap images of Discovery'sexternal tank as it falls away, Green added. The digital camera replaces anolder 35 millimeter film camera and should allow mission controllers to viewimages of the external tank just after launch, instead of after a shuttlelanding as in previous flights, he said.

Shuttle engineers have also laid the groundwork for a50-foot (15-meter) inspection boom that would allow astronauts to checkDiscovery's underside for signs of tail damage is also complete, though NASAengineers are behindin developing the boom itself.

"The wiring is there and waiting for the boom to arrive,"Stilson said.

NASA engineers have also incorporated new screeningtechniques for the reinforced carbon-carbon (RCC) panels protecting each ofDiscovery's wings from the heat of reentry. Visual inspections and flashthermography, which exposes the panel to intense heat to look for defects,should sniff out any problems before and after shuttle flights. If defects arefound, the panels can be removed and replaced or sent back to theirmanufacturer - Lockheed Martin - for repair.

"Discovery is in real good shape right now," said KenWagner, a United Space Alliance systems specialist overseeing the RCCmodifications.

Stationbuilding

Discovery's March flight is expected to put NASA back ontrack with ISS construction, which officials said could be finished by the endof the decade.

In a July 23 meeting ofISS international partners NASA officials said all participating nations haveagreed to a broad framework to bring the orbital platform's construction tocore completion.

NASA space station director Bill Gersteinmeier, who attended the meeting inNoordwijk, Netherlands with NASA associate administrator Fred Gregory, said ina conference call with reporters that ISS construction missions will include aseries of station truss installation in 2006, as well shuttle flights todeliver the Japanese Experiment Module (JEM) and the European Columbus OrbitalFacility in 2007.

But any delay in Discovery's next launch would mostdefinitely push that assembly schedule back.

"All our partners are aware that we could slip from aMarch to April time frame," Gregory said of the return to flight. "We would doeverything we can to make sure the station reaches its complete configurationby the end of the decade."