Roger Mark Boisjoly was an American
mechanical engineer,
fluid dynamicist, and an
aerodynamicist who worked for
Morton Thiokol, the manufacturer of the
solid rocket boosters
(SRBs) for the Space Shuttle program died from cancer he was 73.. Prior to his employment at
Thiokol, Boisjoly worked for companies in California on lunar module
life-support systems and the moon vehicle.
[2] He is best known for having raised objections to the launch of the
Space Shuttle Challenger the day before the loss of the spacecraft and its crew.
(April 25, 1938 – January 6, 2012)
O-ring safety concerns
Boisjoly wrote a memo in July 1985 to his superiors concerning the
faulty design of the solid rocket boosters that, if left unaddressed,
could lead to a catastrophic event during launch of a
Space Shuttle. Such a catastrophic event did occur less than a year later resulting in the
Space Shuttle Challenger disaster.
This memo followed his investigation of a solid rocket booster (SRB) from a
shuttle flight in January 1985. During his investigation, he discovered that the first of a system of two
O-rings had failed completely, and that some damage had been caused to the second O-ring.
The O-rings were two rubber rings that formed a seal between two
sections of the SRBs. The sections of the boosters were joined using
tang and clevis joints
and the rings were intended to seal the joint, while allowing for the
inevitable movement between the sections under flight conditions. By
design, pressure from within the booster was to push a
fillet
of putty into the joint, forcing the O-ring into its seat. The system
never functioned as designed. The rings were supposed to sit in a groove
and seal the joint between the sections of the booster. It was found,
however, that flight dynamics caused the joints in the SRB's to flex
during launch, opening a gap through which rocket exhaust could escape.
As the joints flexed, the rings would come out of their grooves and move
to a new position in the joint, a process called extrusion. The
extruded ring would form a seal in this new position, but during the
time it took for the ring to shift, the joint was unsealed and hot
gasses could escape, a process called blow-by. These hot gasses would
cause damage to the rings until the seal was achieved.
Boisjoly's investigation showed that the amount of damage to the
O-ring depended on the length of time it took for the ring to move out
of its groove and make the seal, and that the amount of time depended on
the temperature of the rings. Cold weather made the rubber hard and
less flexible, meaning that extrusion took more time and more blow-by
took place. He determined that if the O-rings were damaged enough they
could fail.
If the second O-ring had failed, Boisjoly realized, the results would
almost certainly have been catastrophic with the complete loss of the
shuttle and crew seemingly the only outcome. His investigation found
that the first O-ring failed because of the low temperatures on the
night before the flight had compromised the flexibility of the O-ring,
reducing its ability to form a seal. The temperature at launch had been
only 10 °C (50 °F), the coldest on record (until January 28, 1986). The
first rubber O-ring had formed a partial seal, but not a complete one,
but the second O-ring had held.
Boisjoly sent a memo describing the problem to his managers, but was apparently ignored.
[3]
Following several further memos, a task force was set up – including
Boisjoly – to investigate the matter, but after a month Boisjoly
realized that the task force had no power, no resources and no
management support. In late 1985 Boisjoly advised his managers that if
the problem was not fixed, there was a distinct chance that a shuttle
mission would end in disaster. No action was taken.
Challenger disaster
Following the announcement that the
Challenger mission was confirmed for January 28, 1986, Boisjoly and his colleagues tried to stop the flight. Temperatures were due to be down to
−1 °C (30 °F) overnight. Boisjoly felt that this would severely compromise the safety of the O-ring, and potentially lose the flight.
The matter was discussed with Morton Thiokol managers, who agreed
that the issue was serious enough to recommend delaying the flight. They
arranged a telephone conference with
NASA
management and gave their findings. However, after a while, the Morton
Thiokol managers asked for a few minutes off the phone to discuss their
final position again. Despite the efforts of Boisjoly and others in this
off-line briefing, the Morton Thiokol managers decided to advise NASA
that their data was inconclusive. NASA asked if there were objections.
Hearing none, the decision to fly the ill-fated
STS-51L Challenger mission was made.
Boisjoly's concerns proved correct. In the first moments after
ignition, the O-rings failed completely and were burned away, resulting
in the black puff of smoke visible on films of the launch. This left
only a layer of insulating putty to seal the joint
[citation needed].
At 59 seconds after launch, buffeted by high-altitude winds, the putty
gave way. Hot gases streamed out of the joint in a visible torch-like
plume that burned into the external hydrogen tank. At about 73 seconds,
the adjacent SRB strut gave way and the vehicle quickly disintegrated.
Boisjoly was relieved when the flight lifted off, as his
investigations had predicted that the SRB would explode during the
initial take-off. However, seventy-three seconds later, he witnessed the
shuttle disaster on television.
Later career
After President
Ronald Reagan
ordered a presidential commission to review the disaster, Boisjoly was
one of the witnesses called. He gave accounts of how and why he felt the
O-rings had failed. After the commission gave its findings, Boisjoly
found himself shunned by colleagues and managers and he resigned from
the company.
Boisjoly became a speaker on workplace ethics.
[4]
He argued that the caucus called by Morton Thiokol managers, which
resulted in a recommendation to launch, "constituted the unethical
decision-making forum resulting from intense customer intimidation."
[5]
For his honesty and integrity leading up to and directly following the shuttle disaster, Boisjoly was awarded the
Award for Scientific Freedom and Responsibility by the
American Association for the Advancement of Science in 1988.
[1][4]
When Boisjoly left Morton Thiokol, he took 14 boxes containing every
note and paper he received or sent in seven years. On May 13, 2010, he
donated his personal memoranda — six boxes of personal papers, including
memos and notes from congressional testimony — to
Chapman University in
Orange, California.
Rand Boyd, the special-collections and archival librarian at Chapman's
Leatherby Libraries, said the materials will be catalogued and archived.
It was to be about six months to a year before library visitors would
be able to view the materials.
[6]
Boisjoly died on January 6, 2012, of cancer of the colon, kidneys, and liver.
[2]
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