CAPE CANAVERAL - NASA's shuttles are set to return to flight with 90 percent fewer known problems -- many of which could prompt disaster -- than were on the books when Columbia blasted off on its doomed flight in 2003.
An exhaustive two-year review of every known violation of shuttle engineering and safety requirements has slashed the number of "waivers" of those requirements from nearly 6,000 to about 500, shuttle program officials said.
The review, in response to criticism from outside reviewers and a recommendation by the Columbia Accident Investigation Board, has left decision-makers with a far more manageable number of potential dangers to track.
Reviewers identified thousands of waivers for parts that no longer fly, systems that have since been redesigned or procedures no longer relevant to the kinds of missions the orbiter flies. Eliminating unnecessary and obsolete waivers gives managers a clearer view of the ones that do pose risk to the remaining shuttles and the astronauts aboard, the agency says.
said Wayne Hale, deputy manager of the Space Shuttle Program at Johnson Space
Center, "we have a much more useful system since we have eliminated the
clutter and out-of-date paperwork. Now, the remaining waivers will be something
that keeps management attention focused on
our real problems and the open work ahead of us."
In the summer following the Columbia accident, FLORIDA TODAY reported the shuttle launched with twice as many waivers of accepted flaws in critical systems -- those which could lead to the destruction of an orbiter and loss of astronauts on board -- as were in place when the Challenger exploded during launch in 1986. The number was 1,672.
The newspaper identified excessive waivers as one of seven problems NASA needed to fix before it could return its orbiter fleet to space. The Columbia Accident Investigation Board expressed concern about the number of waivers, and they recommended an independent group rather than shuttle program managers be given sole authority to grant waivers.
No fewer than five independent oversight groups, including the Challenger investigators, previously criticized NASA for failing to reform its system for granting waivers to original requirements set by the engineers who designed the shuttle.
The waivers amount to decisions by managers to accept the risk posed by defects in the orbiters, solid rocket boosters, fuel tanks and other equipment.
The shuttle is the most complex aircraft ever flown. It's a conglomeration of systems that must work in concert to ensure safety and success. Every part has detailed requirements, as does the system as a whole. In 22 years of shuttle flights leading up to Columbia's fateful launch, however, NASA often had discovered components not working quite right.
That is a quandary for engineers and managers. They can redesign the system to meet requirements or disregard the standard. If they disregard it, engineers must analyze the danger and make sure the chance of failure is so remote that the risk is acceptable. The process ends with written documents prepared to convince managers the shuttle is safe to fly as-is.
Several safety groups, however, said NASA's practice over the years showed the agency was more likely to waive requirements than fix the problem. Often, they found, the space agency would grant a waiver that would never go away. In 2003, most of the waivers on the books had been in place since a purge prompted by the Challenger accident.
Whether each individual defect represented a credible threat to the ship, many safety advocates -- including Columbia investigators -- said the sheer number and age of the waivers made it impossible for managers to have a complete understanding of all of the risks they were accepting with each launch.
The number of waivers and the way NASA approves them "makes the risks accepted for launch invisible to space shuttle program managers in their decision-making," said the Shuttle Independent Assessment Team during a wide-ranging investigation that followed a near-disastrous engine malfunction during a 1999 Columbia launch.
The post-Columbia review has identified hundreds of waivers for parts that were deficient but aren't flying any more, according to Hale and NASA's internal records. Other purged waivers were for gear that has been redesigned or eliminated. Some were just duplicates. A single type of problem could result in hundreds of separate "waivers."
The shuttle program is preparing the specific numbers for its Flight Readiness Review the last week of June at the Kennedy Space Center. Not all of the remaining 500 or so waivers are for problems with the most critical systems -- flaws that could lead to another disaster. That number was not immediately available.
However, the lower number is a positive step that "allows the SSP management to understand which waivers represent real safety issues and which were merely administrative. This in turn clarifies the level of risk associated with each waiver," the space agency reported in the latest version of its return to flight plan.
Published under license from FLORIDA TODAY. Copyright ? 2005 FLORIDA TODAY. No portion of this material may be reproduced in any way without the written consent of FLORIDA TODAY.
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