From: University of Tennessee at Chattanooga
Posted: Friday, March 7, 2003
On July 25th of 1999, during the flight of the space shuttle Columbia, commanded by Eileen Collins, two separate malfunctions occurred which set in motion a significant chain of events. At takeoff, a pin broke loose and ruptured cooling tubes to the vehicle’s main engines, causing a slight reduction in the eventual orbital altitude. Separately, during the same launch, two of the shuttle’s engine controllers unexpectedly shut down. By design, backups seamlessly activated and assumed the lost controllers functions. The vehicle made it to orbit, completed its mission and returned home safely.
A pattern of minor failures had emerged that suggested to NASA engineers that a nascent wiring problem existed across the entire shuttle fleet. After being informed of the engineers' concerns, NASA officials immediately ordered wiring inspections of all four shuttles. Subsequent inspections confirmed the engineer's suspicions as similar wiring damage was noticed in every vehicle. The Agency grounded the shuttle fleet while repairs were affected.
NASA administrators also ordered a comprehensive review of the space shuttle program with regards to safety and empowered an independent panel of experts to that end. The group, which I chaired, was known as the Shuttle Independent Assessment Team or SIAT. Our mandate from NASA was to evaluate the Shuttle program operations, maintenance processes and maintenance procedures and make recommendations for improvements without regard to cost. The administrator at the time, Dan Goldin, urged me to "leave no stone unturned." Our work stretched from October of 1999 to March of 2000.
Among our more than 90 findings, SIAT determined that processes, procedures and training, which had evolved over the years that had made the shuttle safer, had, in fact, been eroded. The major reason for this erosion was the reduction in allocated resources and appropriate staff. I believe the report is quite detailed and stands on its own merits. NASA agreed with our observations on this staffing issue and immediately moved to stop further shuttle staffing reductions, added safety inspections and sought additional resources for the program. Wiring inspections and repairs were extensively performed and monitored. One hundred new inspectors were promptly added to the roles at Kennedy and 800 more scheduled for addition in the next two years.
Following an extensive internal review many of our over 120 recommendations were acted on without delay. Some, it was felt would not be effective. Others requiring significant resources or longer time were not implemented or deferred until later. I was disappointed that more of the team's recommendations could not be implemented.
Documentation of the disposition of the SIAT recommendations exists and was requested of NASA and became available to me yesterday, March 5. The interested reader can review the documents and the SIAT response for themselves as I believe they will be posted on the web.
In the SIAT report it was recommended that the implementation process be examined later by another independent review team. It was also recognized by SIAT that our particular team did not have the technical expertise to perform an in depth review of the other components of the Space Transportation System similar to what we had performed on the Orbiter. However in the light of what was learned on the Orbiter the Team felt that a number of the issues were systemic in nature and that such an investigation of the other system components was necessary. Accordingly it was one of the reports recommendations that an independent panel of appropriately qualified experts be formed to perform reviews of the Space Shuttle Main Engine, the Solid Rocket Motor and the External Tank. The SIAT report is available from http://www.hq.nasa.gov/osf/siat.pdf
The members of the SIAT were asked for their views on the safety of the vehicle (OV103) for a return of the vehicle to flight status. Much discussion of this request took place and it was concluded that the SIAT response should be carefully restricted to a statement that in light of the extensive inspections of the vehicle which had been undertaken and upon completion of some additional wiring inspections that we had recommended, it was likely that the vehicle would possess less risk than other Orbiters which had recently flown. SIAT did not express a view on the absolute level of flight risk, but expressed a view of the flight risk relative to other recent Shuttle Orbiter flights.
I would like to conclude by recalling two statements from our report, one being "The Shuttle program is one of the most complex engineering activities undertaken anywhere in the world at the present time" and the other being "The SIAT was continually impressed with the skill, dedication, commitment and concern for astronaut safety of the entire Shuttle workforce". I see no reason to qualify either of these remarks today.
Henry McDonald, D.Sc.
Distinguished Professor, Chair of Excellence in Engineering
University of Tennessee at Chattanooga
Thursday, March 06, 2003
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