On January 28, 1986, the Space Shuttle Challenger broke apart 73 seconds after launch, killing all seven crew members. Engineers had warned NASA managers that the rubber O-rings used to seal joints on the solid rocket boosters could fail in the abnormally cold launch conditions. However, NASA managers decided to proceed with launch despite the risks. The subsequent investigation found that NASA had known about potential problems with the O-rings for years but failed to address the issue. This tragedy highlighted flaws in NASA's risk management and decision-making processes.

1. CHALLENGER SPACE SHUTTLE
INCIDENT

2. What happened
On the morning of January 28, 1986,
despite concerns within NASA and
among others working on the launch
that the weather was too cold, the
shuttle Challenger blasted off.
Seventy-three seconds later, it broke
apart in long, grotesque fingers of
white smoke in the sky above Cape
Canaveral, Florida.

3. Challenger’s catastrophic launch
• The missions’ launch from Kennedy Space Centre at Cape
canaveral, Florida, was delayed for six days due to weather and
technical problems. The morning of 28 January, 1986
was unusually cold and engineers warned
their superiors that certain components,
the rubber O Rings that sealed the joints
of solid rocket booster were vulnerable to
failure at low temperatures. However, these
warnings were ignored and at 11:39 a.m.
challenger lifted off.
• Seventy three seconds later the shuttle broke up in a forking plume
of smoke and fire. Within instants, the spacecraft broke apart and
plunged into the ocean, killing all seven crew members, which
consisted of five NASA astronauts and two payload specialists.

4. Causes
• Inadequate design: The O-Ring was a rubber seal component in
the solid rocket booster (SRB), its purpose was to stop leaks. Due to
extremely cold temperature on the day of launch, the O-Ring lost its
elastic property and became brittle (inflexible), allowing a leak and
resulting in explosion.
• Faulty judgment (managers decided to launch despite record low
temperatures and ice on launch pad)
• Possible unanticipated external events (severe wind shear may
have been a contributing factor).

5. Management problems
The Rogers Commission (a special commission appointed by US President to
investigate the accident) found NASA's decision-making processes had been
key contributing factors to the accident, with the agency violating its own
safety rules.
• NASA managers had known since 1977 that the design of the SRBs
contained a potentially catastrophic flaw in the O-rings, but they had
failed to address this problem properly.
• NASA managers also disregarded warnings from engineers about the
dangers of launching posed by the low temperatures of that morning, and
failed to adequately report these technical concerns to their superiors.

6. Technological improvements and
lessons learned
• In design, to use probabilistic risk assessment more in evaluating
and assigning priorities to risks.
• In operation, to establish certain launch commit criteria that cannot
be waived by anyone.
• Knowing the limitations of your equipment or product .
• Knowing the validity of certifications and specifications.
• Knowledge of past problems and anomalies.
• Importance of proper and clear communication.
• Never presume anything – check and double check.
• Challenge assumptions and basis for analysis with simple
calculations and gut feelings.

7. Other OUTCOMES
• Redesign of booster joint and other shuttle subsystems that also had
a high level of risk or unanticipated failures.
• Reassessment of critical items.
• Challenger's explosion changed the space shuttle program in
several ways. Plans to fly other civilians in space (such as
journalists) were shelved for 22 years, until Barbara Morgan,who
was McAuliffe's backup, flew aboard Endeavour in 2007. Satellite
launches were shifted from the shuttle to reusable rockets.
Additionally, astronauts were pulled off of duties such as repairing
satellites, and the Manned Maneuvering Unit was not flown again, to
better preserve their safety.