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He can't explain how NASA engineers missed the error, AbuTaha says, unless they were so concerned with the moment of liftoff and the few milliseconds after that they ignored the rest of the curve. "We have specialists who know everything about nothing," he says, "and generalists who know nothing about everything."
AbuTaha thinks NASA eventually adopted some of his findings without credit and used them in redesigning the space shuttle. But he claims that instead of remedying the fundamental problem, NASA has taken a Band-Aid approach, adding structural reinforcements to the lower section of the assembly. This has only shifted the liftoff stress to the cargo bay. One by one, AbuTaha ticks off recent satellites that failed after they were released from the shuttle's cargo bay: a Defense Department satellite payload that malfunctioned and burned up in Earth's atmosphere; camera problems in the Jupiter-bound Galileo probe; the trouble the Hubble Space Telescope had with its antenna, computers, and navigational system.
"These are problems that have nothing to do with lens grinders," he protests.
He was at home conducting research the morning the Challenger exploded, AbuTaha recalls. "The launch had been delayed several times, so I wasn't watching it on TV. My daughter came running in to tell me. I walked to the TV, saw the explosion, and still didn't
When the Rogers Commission released its report five months later, AbuTaha picked up a copy for professional reasons. Poring over its 3000 pages, he quickly suspected that some of the figures, such as the 291,000,000 inch-pound figure for the bending moment, were impossibly low. But if the vehicle had been overstressed from the beginning, the fact remained that 24 missions had flown without a major hitch. What made the Challenger different?
AbuTaha toyed with the idea that the shuttle assembly might have sustained structural damage before the launch. The Challenger was the first shuttle to be launched from pad 39B at Cape Canaveral. On the way from the assembly building to the liftoff site, the vehicle transporting the shuttle must make a sharp left turn. If the bulky but delicate shuttle assembly were to lean too far in one direction, he reasoned, it could be
AbuTaha approached NASA with his insights - eager to share his findings for the good of the space program. But he makes no bones about another incentive: as he turned up evidence of a major oversight in design, he hoped to land a sizable contract for his labors. A consulting contract of $75,000 to $100,000 was not out of the question.
On June 16, 1986, AbuTaha wrote then NASA director James C. Fletcher, current director Richard Truly, and others in the agency, advising them to search for "preflight" loads - damage caused to the shuttle before it left the ground. He also informed them of his "sharp left turn" theory. NASA took AbuTaha seriously enough that it allowed him to witness the roll-out of the shuttle Atlantis in October 1986. According to Myron Uman, who oversaw the redesign of the solid-fuel booster, NASA arranged the roll-out to test AbuTaha's theory, strapping stress gauges on the assembly. AbuTaha later discounted the sharp left turn theory as the major cause of the accident, although he still believes the stress might have been the nudge that sent the Challenger over the edge.
But that early, imperfect theory did not dissuade AbuTaha. Soon he was devoting virtually all his energy to his shuttle investigation without reimbursement - searching for forces unaccounted for in the official version. In an October 7, 1986, brainstorming session with NASA engineers at the Kennedy Space Center, AbuTaha says, he first learned about the change in launch procedure.
While at Cape Canaveral, AbuTaha was advised by Horace Lamberth, then director of shuttle engineering, to carry on his investigations. Lamberth referred him to the Marshall Space Flight Center in Huntsville, Alabama. AbuTaha wrote up his new suspicions about altered launch procedures in a report entitled, "A Failure Mode and a Missing Baseline," and submitted it to Marshall. On October 30, 1986, John Thomas, manager of the team that designed the solid rocket motor, responded to AbuTaha: "It is my view that it is unnecessary to pursue the thoughts contained in your report."
AbuTaha's criticisms were also dismissed by Admiral Richard H. Truly, then associate administrator for space flight, now head of NASA. "The configuration of the Shuttle at liftoff presents a very complex structural analysis challenge," Truly wrote. "The analytical models used for these calculations have evolved over the years and have proven to produce accurate predictions on how the various elements of the shuttle will behave when exposed to a given set of conditions. This flight was no exception."
In November 1986 AbuTaha's attorney, William D. Blakely, delivered a copy of his latest report to Morton Thiokol, the Utah firm that manufactured the shuttle's solid-fuel boosters. Thiokol's T.F. Garrison wrote, "The report is interesting and well-written," but sidestepped the questions AbuTaha raised. "We are solid-propellant rocket motor people and not expert on either vehicle dynamics or liftoff/flight loads. Therefore, we are not in a position to comment on or meet with Mr. AbuTaha concerning his report."