New Damage Detection Sensors Not Ready To Fly

More than two years of careful investigation and painstaking planning may come down to the last minute in NASA's attempt to return its remaining shuttle fleet to service in May. Even though Discovery's launch date has been set, not everything NASA pledged to the Columbia Accident Investigation Board has come to fruition. In this case, the new sensors designed to detect fatal hull breaches may not actually work until the very last minute before launch.

"We expect that an army of engineers and scientists on the ground will be working this (inspection) problem very hard right up till the day of launch," said rookie astronaut Charles Camarda in an interview with USA Today.

NASA Space Operations chief William Readdy, though not specifically asked about the sensor issue, told USA Today he sees no major roadblocks to the May 15th return to flight.

But USA Today reports there are a number of issues addressed by the CAIB that are still in the works:

• Engineers will have to resolve what appears to be a major miscalculation. In the wake of the hull breach that doomed Columbia, NASA officials believed that, upon re-entry, the leading edges on the shuttles' wings could withstand a crack wider than 0.2 inches. That's apparently not the case. Three weeks ago, according to USA Today, engineers came to believe a crack less than one-tenth of that width could be potentially fatal.
• A relatively inexperienced team of Boeing engineers monitoring Columbia's final, tragic flight initially disregarded a computerized damage projection based on data from the impact of fuel tank foam on Columbia's wing. The projection indicated the damage was fatal. But the Boeing engineers, many working on their first live space mission, decided the projection was faulty. The engineers took a lot of heat over their decision and NASA took quite a bit as well, for accepting the Boeing report even though parts were incomplete. More than two years later, the computer projections still have not been independently reviewed.
• Three months before Discovery's return to flight, there are still no firm procedures for scanning the shuttle to detect damage prior to re-entry. Astronauts haven't been able to train on damage inspections.

  

"We're kind of taking these sensor systems to their limit, and we need to understand what the limits are," Camarda told USA Today.

FMI: www.nasa.gov/news/highlights/returntoflight.html