CAPE CANAVERAL, Fla., March 25 (UPI) -- NASA violated the space shuttle's operating parameters by continuing to fly despite foam insulation falling off the fuel tank and striking the ship, a launch vehicle and space systems expert testifying before the Columbia accident investigation board said Tuesday.
"There's no way you can say you are operating within margins if you have debris at high speeds striking aerodynamic surfaces," said retired Air Force Lt. Gen. Aloysius Casey, a management and technical consultant. "Clearly when the shuttle was designed 113 flights ago, this situation was not intended."
Shuttle Columbia's left wing was hit by falling foam insulation during its launch Jan. 16. The spaceship was destroyed 16 days later as it attempted to re-enter Earth's atmosphere, killing seven astronauts. The investigation board has not determined what effect, if any, the debris impact had in the accident, but NASA already is taking steps to fix the problem. The panel has determined a breach in Columbia's left wing allowed superheated plasma to enter the wing, dooming the ship and its crew.
During a public hearing, Casey told the board the shuttle is so complex any safety upgrades will bring negligible results.
"It's impossible for a system as large and complex as the space shuttle to identify the next failure mode," he said, suggesting that NASA reduce the size of its crews and only use the shuttles for missions that cannot be flown on expendable rockets.
NASA's inability to see that the falling foam issue, which had occurred on several previous flights, harkens back to shuttle Challenger days, when problems with leaking O-rings in the solid rocket boosters were largely ignored until Jan. 28, 1986, when a leaking seal triggered a deadly explosion, claiming seven lives.
The agency should be aware at all times of the shuttle's engineering environment so any steps beyond design parameters are instantly flagged. The task is complicated by the shuttle's aging and other factors that change the original condition of the hardware.
"Successful flights should not be used as evidence that everything is OK," said Casey. "The only way to determine margins is to test with more stress than you are going to encounter in flight."
Board Chairman Harold Gehman told Casey his words rang true.
"There is no question NASA looks at the shuttle program through a microscope," he said. "They need to take a step back and look through a telescope."