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

Slated for launch sometime between March 6 to April 18 in 2005, Discovery's STS-114 mission is expected to test out in-flight shuttle repair techniques, as well as new sensors and a camera to keep ground crews apprised of the spacecraft's health. The mission will also deliver supplies and much needed equipment to the International Space Station (ISS).

"I feel very comfortable that we can make a March 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 over the hump."

Stilson said Discovery's return-to-flight modifications should be complete in the next few months, with rollout currently scheduled for early January.

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

Prepping Discovery

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

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

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

Green said the new sensors will be able to take 20,000 samples per second as Discovery rockets into space, and are should function in orbit to detect micrometeorite impacts. Each wing will carry 22 temperature sensors and 66 accelerometers designed to monitor any impacts when the modifications are complete. Data will be relayed to ground control in Houston via a laptop connection in the orbiter's crew compartment.

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

Shuttle engineers have also laid the groundwork for a 50-foot (15-meter) inspection boom that would allow astronauts to check Discovery's underside for signs of tail damage is also complete, though NASA engineers are behind in developing the boom itself.

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

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

"Discovery is in real good shape right now," said Ken Wagner, a United Space Alliance systems specialist overseeing the RCC modifications.

Station building

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

In a July 23 meeting of ISS international partners NASA officials said all participating nations have agreed to a broad framework to bring the orbital platform's construction to core completion.

NASA space station director Bill Gersteinmeier, who attended the meeting in Noordwijk, Netherlands with NASA associate administrator Fred Gregory, said in a conference call with reporters that ISS construction missions will include a series of station truss installation in 2006, as well shuttle flights to deliver the Japanese Experiment Module (JEM) and the European Columbus Orbital Facility in 2007.

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

"All our partners are aware that we could slip from a March to April time frame," Gregory said of the return to flight. "We would do everything we can to make sure the station reaches its complete configuration by the end of the decade."