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The Space Shuttle Challenger Disaster
The Space Shuttle Challenger Disaster
The “Teacher in Space” Mission
At 11:38 am on January 28th 1986,
the 25th Space Shuttle mission
began with Challenger lifting off
the launch pad at the Kennedy
Space Center in Florida.
Approximately 73 seconds later,
the Challenger was engulfed in a
fireball. Seven crew members lost
their lives.
The high profile nature of the
“Teacher in Space” mission
required an independent
commission to review the accident
and risk management processes
that were in place at NASA and
associates at the time.
The Space Shuttle Challenger Disaster
The NASA Space Program after Apollo
When the Apollo program finished in the
1970s, NASA had begun planning for the next
phase of space exploration, an interplanetary
expedition to Mars. This involved three core
projectsA Space Shuttle- A reusable transport vehicle
A Space Station- The launch platform
Manned Mars exploration
Due to budgetary constraints, only one of
these NASA projects could be supported.
The Space Station concept was favoured by
President Nixon. However, this required the
development of the Space Shuttle to support
the project.
The Space Shuttle Challenger Disaster
Feasibility study for the Space Shuttle concept
An initial 1972 study by the Mathematica
organisation found that the space shuttle
could orbit payloads for as little as $100 US
per pound, on sixty launches per year with
the initial shuttle design specifications (69,000
pound payload capacity).
This offered military, satellite deployment,
scientific and medical research applications
with a very cost effective option.
However the Mathematica report was based
on unrealistic costings provided by
contractors to win NASA tenders.
Additionally equipment performance
shortfalls prevented the 109% of thrust
required by NASA, further reducing payload
capacities. The actual cost for payloads
became 20 times the original estimate.
The Space Shuttle Challenger Disaster
The push to market the new technology
During the development of the Space Shuttle,
the European Space Agency began commercial
satellite operations, increasing the market
competition.
NASA, in an attempt to remain market leader,
partnered with the United States Air Force for
the development of the Space Shuttle program
With financial and political pressures in place,
key engineering design compromises were
made on the Space Shuttle. These were• Use of Solid Rocket Boosters (SRB)
• Payload Bay size and shape adjustments
• Removal of Air breathing engines
• Removal of the Evacuation System
These changes affected the weight and
characteristics of the vehicle, reducing safety
factors and versatility in the Space Shuttle.
The Space Shuttle Challenger Disaster
The push to market the new technology
Solid Rocket Boosters
NASA’s initial space shuttle design was with all
liquid-fuelled rockets, following on from Apollo
and the Saturn V rocket. Liquid based
propulsion can be shut down in the event of
catastrophe.
However the decision was made to use cheaper,
reusable Solid Rocket Boosters (SRB) for the
shuttle program. Solid Rocket Boosters need to
expend all fuel during liftoff to separation.
The Rogers Commission found“The Space Shuttle System was not designed to
survive a failure of the Solid Rocket Boosters. There
are no corrective actions that can be taken if the
boosters do not operate properly after ignition, i.e.,
there is no ability to separate an Orbiter safely from
thrusting boosters and no ability for the crew to
escape the vehicle during first-stage ascent.”
The Space Shuttle Challenger Disaster
The push to market the new technology
Quality
In 1973, after final design considerations of
the Space Shuttle had taken place, NASA
began the tendering process. This process
was based primarily on cost considerations.
Cost
Time
NASA considerations
Rockwell International won the contract for
the construction of the Space Shuttle (also
known as the Orbiter Space Vehicle). This
was despite the safety concerns that
Rockwell’s proposal did not include any
escape system.
Morton-Thiokol Inc won the contract for the
Solid Rocket Booster (SRB) component of
the design. This was awarded due to the
cost, $100 million cheaper than the next
competitor, over the technical design and
safety aspects.
The Space Shuttle Challenger Disaster
Risk management
Safety testing
The SRB did not have adequate safety testing
and part replacement programs in place.
Before reuse of the SRB, engineers would test
the O ring seals for deterioration and failure.
This involved blowing air into the seal to check
integrity. The test was also responsible for
doing some damage to the seal.
At lower temperatures, it became evident that
the materials used in the O ring design were
less likely to seal correctly. The recent change
to an asbestos-free putty, used as a backup to
the seal, also became more brittle and less
flexible during colder conditions.
The lack of spare parts due to budget
constraints further compounded the SRB
safety.
The Space Shuttle Challenger Disaster
Risk management
The risk management process at NASA and
Morton-Thiokol Inc involved the followingA Flight Readiness Review (FRR) meeting which
covered the following• Determine the overall mission status
• Review significant problems
• Review all constraints
• Present all new waivers from the last flight
Previous Space Shuttle missions had uncovered a
flaw in the seal on the SRB, with damage to the O
rings becoming more evident, especially in cooler
conditions. Despite this a waiver was placed,
allowing missions to continue unabated.
The risk management process remained a
qualitative process, whereby a low aggregate risk
remained acceptable.
The Space Shuttle Challenger Disaster
Risk management
Current risk management
processes involve the following• Risk Identification
• Risk Assessment
• Risk Response Development
• Risk Response Control
NASA had a well established, albeit
simple, risk classification system.
The O ring component that failed
in the launch of Challenger was
initially classed as Criticality 1 in
1982, but later reclassified to C1R
(redundancy in place)
Morton Thiokol responsibility to
mitigate this risk was poor, as
reported by an internal memo
from Richard Boisjoly 6 months
previously.
The Space Shuttle Challenger Disaster
Politics, Infighting and Chain of Command
NASA, without a permanent administrator for
4 months before the Challenger incident, were
in management disarray.
Additionally, the Flight Center Director in May
1985 imposed that NASA schedules would
remain on target throughout the 1985-86 fiscal
year.
Despite this, delays were
still occurring and media
pressures were ever
constant. This mounted a
toll on NASA to deliver.
The lower level
employees at NASA were
constrained through the
bureaucracy to prevent
the launch of Challenger.
The Space Shuttle Challenger Disaster
Politics, Infighting and Chain of Command
At Morton-Thiokol Inc the management were also
under considerable pressure. During a pre-flight
meeting, NASA’s Mulloy, already stressed from
previous mission delays, demanded Morton-Thiokol
Inc reassess the position to stop the launch.
Morton Thiokol then held a 30
minute conference with senior
engineers. As there was no
sustainable argument regarding
the O ring seal problem in colder
conditions, management made
the decision to reverse its original
position and give the all clear.
NASA interpreted this as an
acceptable risk and went to
launch the mission.
16358573 Michael Monteleone , 16554131 Vijay Karigiri, 16569078 David Alexander
The Space Shuttle Challenger Disaster
The Rogers Commission Report Findings
The Mechanical Cause of the Accident
The consensus of the Commission was the
mechanical cause of the accident was due
to a joint failure in the lower two segments
of the right Solid Rocket Motor (SRM).
The failure was due to a faulty design
unacceptably sensitive to a number of
factors.
These factors were the effects of
temperature, the physical dimensions, the
character of materials, the effects of
reusability, processing and the reaction of
the joint to dynamic loading.
These factors in combination were
considered to be the most likely causes of
mechanical failure in the Space Shuttle
Challenger destruction.
The Space Shuttle Challenger Disaster
The Rogers Commission Report Findings
The investigation focussed on the followingEnvironmental conditionsThe ambient temperature was 36º F, 15º F colder than
the next coldest launch. Additionally, water from
previous rainfalls may have been present in the joints,
freezing at the cooler temperatures and preventing
proper seal performance
Mechanical conditionsA combustion gas leak occurred in the right SRM
during the ignition process which weakened the joint.
No other Shuttle element or the payload contributed
to this leak.
Procedural complianceNo flight hardware at the launch site were outside
Shuttle design specifications, launch site activities
were conducted in accord with established procedures.
The right SRM were assembled using approved
procedures and sabotage was not a factor.
The Space Shuttle Challenger Disaster
The Rogers Commission Report Findings
The Underlying Cause of the Accident
The commission found the underlying
cause of the accident was due to poor
decision making regarding the mission
launch.
This is comprised of the following factors• The lack of a well structured and
managed safety system
• Waiving of launch constraints at the
expense of flight safety
• Containment of serious problems at
Marshall Air Base
• The reversal of the Morton Thiokol
management decision regarding the
launch.
These factors created a complacent “flyfirst, safety later” attitude at NASA
The
TheSpace
SpaceShuttle
Shuttle Challenger
Challenger Disaster
Disaster
The “Teacher in Space” mission had the
following crew members on board the
Challenger vehicle at the time of the disaster
(pictured from left to right)Mission SpecialistPilotPayload SpecialistCommanderPayload SpecialistMission SpecialistMission Specialist-
Ellison Onizuka
Michael John Smith
Sharon Christa McAuliffe
Francis Richard Scobee
Gregory Bruce Jarvis
Ronald Erwin McNair
Judith Arlene Resnik
Their names are commemorated in a plaque at Arlington National Cemetery.
After the Space Shuttle destruction, NASA consoled itself and the nation with the
realization that all frontiers are dangerous and to a certain extent, such a disaster
should be accepted as inevitable. However, this incident was avoidable, and a number
of poor management decisions were made to launch in conditions that were hazardous
and unprecedented at the time. This cost seven astronauts their lives.
The
TheSpace
SpaceShuttle
Shuttle Challenger
Challenger Disaster
Disaster
Lessons learnt
Risk management fundamentals
The Challenger disaster became a
textbook case of project failure and
the lack of properly adhered to risk
management procedures.
The term “heterogeneous engineering”
became synonymous with the Space shuttle
program, as management and engineering
decisions were made to meet organisational,
political and economic needs rather than
specific mission objectives.
Finally, the Space Shuttle program was put
on hold for 32 months for the investigation
and repair process to be effected. Most
senior NASA and Morton Thiokol personnel
took early retirements after the incident.
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