Safety Indicators
Safety Indicators
Safety Indicators
Leading Indicators
The root cause of the accident was the O-ring failure that lead to
escape of gases and ultimately high temperature. To overcome this
difficulty the Solid Rocket Motor Joint can be reengineered to prevent
its failure.
Earlier 2 rings, a primary and a secondary ring was used. The primary
ring would often fail, even in the previous NASA flights. But this issue
was neglected as always the secondary ring would sustain the pressure
and do the job. But in Challengers case the secondary ring could not
hold the pressure of the gases. So to avoid future accidents related to
primary ring, the design should be improved. Also the flight director or
the other concerned designer should not neglect any minor failures for
such a High Reliability Organization. (Report to the President, 1986)
Restructure the NASA Management structure to take important
decisions.
Perform a thorough Failure Mode Effect Analysis of each Space Shuttle
Program before the actual launch of the rocket to access various
possibilities of hazard. And take corrective action and redesigning
steps. (Report to the President, 1986)
Instead of having the flight director to overlook safety, appoint a
separate committee or an organization that will oversight quality
assurance and safe operations. (Report to the President, 1986)
Strictly avoiding rocket launches in bad weather conditions. The major
reason for O-ring failure was low temperature. The ring could sustain
as low as 510 F but during Challenger flight, it had reduced to below 36 0
F. The drop in temperature was accounted as an important factor that
contributed to the failure of sealing function. ( Report to the President,
1986)
Give NASAs top management freedom from pressure launches and
tight schedules. This will ensure corrective action is taken before the
launch.
Avoid rushing for launch and International Space race.
Make provisions for cabin crew escape via ejector seats, pad abort,
water landing, powered flight separation etc. Also if safety issue is
detected during the first few minutes of the flights launch, abort the
mission and separate the external tank which can be disposed of in the
ocean. The orbiter can be safely flown back to the launch pad. ( Report
to the President, 1986)
Hiring quality people and organizing safety orientation will ensure high
safety performance.
The tire, brakes and nosewheel steering system should be improved to
improve landing safety. (Report to the President, 1986)
Promptly report even small failures such as a leakage, dysfunction of a
sensor etc. as such a small error might magnify to a huge disaster.
Effective problem identification and finding immediate remedies
especially for such a High Reliability Organization will create better
safety culture.
Develop a shared organizational culture of reliability across all
members of NASA, utilizing effective communication at the
organizations interfaces.
Prioritize safety of on board crew members when deciding between an
economic loss and life of on board crew members. This is because life
is much more important than the success of the mission. Also, losing
the best crew members would always cost more, as more money would
be drained on new members for training, remuneration of deceased
members etc.
Lagging Indicators
Trends
In 1976, (NASA) unveiled the worlds first reusable manned spacecraft, known
as the space shuttle. Five years later, shuttle flights began when Columbia
traveled into space on a 54-hour mission. Launched by two solid-rocket
boosters and an external tank, the aircraft-like shuttle entered into orbit
around Earth. (Space Shuttle Challenger disaster, 2016)
Challenger, NASAs second space shuttle to enter service, made its first trip
on April 4, 1983, and made a total of nine voyages prior to 1986. That year, it
was scheduled to launch on January 22 carrying a seven-member crew.
(Space Shuttle Challenger disaster, 2016)
Challenger was initially planned to be launched from Kennedy Space Centre
in Florida at 14:42 Eastern Standard Time (EST) on January 22. Delays in the
previous mission, STS-61-C, caused the launch date to be moved to January
23 and then to January 24. The launch was then rescheduled to January 25
due to bad weather at the Transoceanic Abort Landing (TAL) site in Dakar,
Senegal. NASA decided to use Casablanca as the TAL site, but because it was
not equipped for night landings, the launch had to be moved to the morning
(Florida time). Predictions of unacceptable weather at KSC on January 26,
caused the launch to be rescheduled for 09:37 EST on January 27. (Space
Shuttle Challenger disaster, 2016)
The launch was delayed the next day, due to problems with the exterior
access hatch. First, one of the micro-switch indicators, used to verify that the
hatch was safely locked, malfunctioned. Then, a stripped bolt prevented the
closeout crew from removing a closing fixture from the orbiter's hatch. By the
time repair personnel had sawed the fixture off, crosswinds at the Shuttle
Landing Facility exceeded the limits for a Return to Launch Site (RTLS) abort.
(Space Shuttle Challenger disaster, 2016). While the crew waited for winds to
die down, the launch window had already passed, forcing yet another delay.
Thiokol engineers, the company that manufactured the O-ring warned of the
incessant low temperature and advised them to postpone the launch till the
weather reached at least 53 0 F.
But due to frequent delays in the launch, NASA Management forced the
Thiokol Engineers to change their statement. If NASA had taken their advice
and rescheduled the launch till suitable temperature was reached, this
accident would have never happened.
After the accident, NASA held back from sending astronauts into space for
more than two years as it redesigned a number of the shuttles features.
Flights began again in September 1988 with the successful launching of
Discovery. Since then, the space shuttle has carried out numerous important
missions, including the repair and maintenance of the Hubble Space
Telescope and the construction of the International Space Station. On
February 1, 2003, a second space shuttle disaster rocked the United States
when Columbia disintegrated upon reentry, killing all the crew members.
While missions resumed in July 2005, the space shuttle is was retired in 2011.
(Report to the President: Actions to Implement, 1986)
From all the line of events that happened, it is very evident that a slight delay
and patience in launching the spacecraft would have saved seven lives,
saved billions of dollars, and delayed missions and cost of opportunity lost.
Summary of the Challenger Episode. (n.d.). Retrieved May 10, 2016, from
http://web1.calbaptist.edu/dskubik/nasa.htm
Report to the President: Actions to Implement the ... - NASA. (n.d.). Retrieved May
10, 2016, from http://history.nasa.gov/rogersrep/actions.pdf
Space Shuttle Challenger disaster. (n.d.). Retrieved May 10, 2016, from
https://en.wikipedia.org/wiki/Space_Shuttle_Challenger_disaster
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