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The Columbia shuttle tragedy: Lessons of the Challenger inquiry
By Shannon Jones
6 May 2003
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The initial phase of the inquiry into the Feb. 1destruction
of the Space Shuttle Columbia reveals the systematic erosion of
safety standards in the space program and the enormous strains
on the space agency resulting from its subordination to commercial
interests and the Pentagon.
The inquiry has substantiated the likelihood that the cause
of the disaster was insulation from the Columbias fuel tanks
breaking loose and damaging the thermal shield on the left side
of the space vehicle. Investigators think that hot gases may have
penetrated the breach in the thermal shield, causing the breakup
of the shuttle during reentry.
The loss of the Columbia and the death of its seven astronauts
followed numerous warnings about the safety of the shuttle program.
Just months before the tragedy a retired NASA engineer wrote president
Bush several letters warning of safety problems with the shuttle.
He urged a moratorium on shuttle missions, citing a multitude
of system failures.
An internal NASA memo written the same year spelled out 30
high risk concerns about the shuttles external
tanks and quality control problems with insulating foam. It warned
specifically about the potential for a missed flaw
leading to failure in flight.
A report submitted to Congress that same year complained that
NASA was understaffed and that employees were overworked
and fatigued. In March of 2001 NASAs Aerospace
Safety Advisory Panel issued a report stating that work on long-term
safety issues had deteriorated. NASA responded by dismissing five
panel members and two consultants.
In the first public hearings held after the loss of the Columbia,
Jefferson Howell, the director of the Johnson Space Center, expressed
concern over the effects of privatization. He testified that of
10,000 people employed at the space center, only 3,000 were NASA
employees. The rest were sub-contractors. He warned that the number
of NASA employees would fall even further.
Ron Dittemore, the program director of the space shuttle, told
panel members that since 1993 the space agency had lost 50 percent
of its civil service technicians and the program was slowly
losing the checks and balances and healthy tensions required
to ensure safety. Several weeks later Dittemore announced his
resignation from NASA.
Despite, or more accurately because of, the wealth of evidence
implicating the White House and top NASA officials in the deliberate
sacrifice of safety in the interests of their corporate-driven
agenda, the inquiry into the Columbia disaster promises to be
a cover-up, in which none of the crucial issues will be seriously
explored.
The Columbia Accident Investigation Board itself is made up
largely of space agency insiders, with most panel members designated
by NASA Administrator Sean OKeefe. Heading the board is
retired Navy Admiral Harold Gehman Jr, former supreme allied commander
of NATO. About half the board members have military backgrounds.
Gehman said the boards charter excludes it from assigning
blame or culpability. Gehman also said that the board may
give witnesses privileged status, allowing their names to
be kept secret. We want to find the causes of this, not
the guilty parties, he added.
The destruction of the Columbia leaves NASA with three shuttles
remaining out of the total of five built. The space shuttle Challenger
exploded after lift-off, killing all seven crewmembers in January
1986.
The Challenger inquiry
The record of the Challenger disaster and subsequent investigative
cover-up bears close examination in light of the ongoing Columbia
inquiry. The events leading up to the destruction of the Challenger
manifested the same intense pressures on NASA staff and a similar
pattern of disregarded warnings culminating in tragedy.
The Challenger explosion was the worst setback to the US space
program up until that time. It was witnessed by millions of people
both on the ground and through live television broadcast. The
flight crew included the first teacher in space, Christa McAuliffe.
President Ronald Reagan appointed a commission to investigate
the loss of the Challenger headed by former Secretary of State
William Rogers. The 20-member panel included individuals from
a broad range of professions. Among the panel members were former
astronaut Neil Armstrong, the first man to walk on the moon, and
Nobel Prize-winning physicist Richard Feynman.
From the outset the commission confronted evidence showing
that NASA officials ordered the launch to go ahead despite safety
warnings. There were charges that the White House had intervened
to prevent further delays in the launch so that it would coincide
with Reagans State of the Union speech to Congress set for
that evening. NASA had submitted to Reagan a paragraph to be included
in the speech saluting McAuliffe.
The blasting of human beings into earths orbit aboard
an explosive-laden rocket at enormous speeds is an incredibly
complex and inherently risky undertaking. The destruction of the
Challenger involved one of the largest non-nuclear explosions
in history, the equivalent of nearly 1000 tons of TNT.
The apparent nonchalance of NASA officials about safety was
appalling. In the final analysis it reflected pressures to maintain
an impossibly ambitious launch schedule set by the military, which
saw the shuttle as the cornerstone of Reagans Star
Wars program, as well as pressures from NASAs corporate
clients.
Budgetary and political pressures affected the ultimate design
of the shuttle. Following the successful moon landings the NASA
budget had been under steady attack, resulting in pressures to
lower design standards in order to cut costs. In order to justify
its budget, NASA had to demonstrate the space programs military
value. This required design modifications affecting the safety
and landing capabilities of the space vehicle.
O-Ring failure pinpointed
The Challenger commission soon established the immediate cause
of the disaster, the failure of the rubber like O-rings joining
the sections of the solid rocket boosters. Feynman established
that the O-ring failed due to record cold temperatures at the
time of the launch.
To dramatize this, the physicist dipped an O-ring into ice
water during a televised session of the commission. The O-ring
immediately became brittle. The lack of resiliency of the O-rings
at relatively low temperatures prevented them from sealing properly,
thus permitting hot gases to escape, resulting in the emission
of a flame from the side of the booster. The flame caused the
main external fuel tank to explode 73 seconds into the launch.
Documents produced in the course of the inquiry showed that
the O-rings had long been a source of concern. The basic design
of the solid booster rocket had been criticized as unsafe as early
as 1972-73, when the shuttle was in its planning stages. In fact
solid rocket boosters were not used during the first 20 years
of the space program because they were considered too risky. However
solid rocket boosters had the advantage of requiring a smaller
a smaller outlay for research and development than did safer liquid
fuel boosters.
Once NASA accepted the plan for a solid rocket booster it attempted
to cut costs further. It rejected a bid for the construction of
a one-piece solid rocket booster that would have eliminated the
need for O-rings. It instead accepted Morton-Thiokols less
costly plan for an SRB built in segments. Political horse trading
also played a role. One reason that Thiokols bid was ultimately
accepted was the fact that the chairman of the Senate committee
overseeing NASAs budget came from Utah, the home base of
Thiokol.
With the start of shuttle missions in 1981 the O-rings continued
to cause concern. A document in 1982 warned that the seals were
a potential source of danger. In fact, during several launches
of the shuttle there had been significant erosion of the O-rings.
A NASA study warned that flight safety was being compromised
by potential failure of the seals. It warned that failure
during launch would certainly be catastrophic. Another report
received by NASA two years before the Challenger explosion pinpointed
the sold rocket boosters as the most dangers component of the
shuttle. It estimated the risk of a catastrophic failure of the
solid rocket boosters at 1 in 35.
While NASA required all shuttle systems to have fail-safe backups,
in the case of the O-rings it made an exception.
There were other safety concerns. Members of the Aerospace
Advisory Panel had warned about a too ambitious launch schedule.
Crews routinely worked seven-day weeks and 10- and 12-hour days.
Pressure for more frequent launches was especially intense from
the Pentagon, which used the space shuttle for lifting spy satellites
and research for Reagans Star Wars program aimed
at developing an anti-missile system.
The launch of the Challenger
Record low temperatures were expected at the time of the Challengers
launch, which had been re-set for January 28 after two previous
delays. The overnight low temperature was 23 Fahrenheit degrees
and launch time temperature was expected to be 38 degrees. The
previous coldest launch temperature had been 53 degrees. In the
hours before the fatal launch, engineers from Morton-Thiokol warned
NASA officials about the potentially dangerous effects of cold
weather on the solid rocket boosters and particularly the O-rings.
The effect of cold on the O-rings was not known at the time.
However, the O-Rings from a shuttle flight launched under cold
conditions the previous year showed significant erosion. Morton-Thiokol
engineers were convinced that cold weather would decrease the
elasticity of the O-Rings, which might impair their ability to
seal properly, and thus could allow hot gases to escape through
the joint.
Reacting to intense pressure to go ahead with the launch, officials
at the Marshall Space Flight Center took the unusual step of asking
Morton-Thiokol to prove that launching the shuttle was unsafe.
Normally NASA demanded the opposite, i.e. that subcontractors
prove a system was safe. When the engineers stuck to their position
that launch conditions were unsafe, Morton-Thiokol management,
not wanting to cause problems for a high profile customer, overruled
them and gave NASA approval to launch.
Rockwell International, the manufacturer of the orbiter, also
expressed concerns about launching in cold conditions. Its engineers
warned that ice from the shuttle or the launch platform could
fall and damage the spacecraft. However, under management pressure,
Rockwell engineers toned down their warnings, merely asserting
that they could not guarantee the safety of the shuttle.
NASA management was determined to press on with the launch
under any circumstances. Having browbeaten its subcontractors
into giving qualified approval for the launch, it decided to go
ahead. NASA never even informed the seven shuttle astronauts of
the engineers concerns.
The commission report
On June 6, 1986 the presidential commission on the Challenger
disaster issued its report. It enumerated a series of safety shortcomings
in the shuttle program. In its findings it stated neither
Thiokol nor NASA responded adequately to internal warnings about
the faulty seal design. It continued NASA and Thiokol
accepted escalating risk apparently because they got away
with it last time. As Commissioner Feynman observed, the
decision making was: a kind of Russian roulette. ... (The
Shuttle) flies (with O-ring erosion) and nothing happens. Then
it is suggested, therefore, that the risk is no longer so high
for the next flights. We can lower our standards a little bit
because we got away with it last time. ... You got away with it,
but it shouldnt be done over and over again like that.
(1)
It concluded that evidence of O-ring erosion prior to the Challenger
flight was significantly severe as to have warranted corrective
action. It noted that an analysis of previous O-ring erosion would
have established a correlation between O-ring damage and cold
temperatures.
The commission recommended changes in the technical and management
problems exposed in the disaster, including the routine issuance
of flight waivers. It also called for a complete redesign
of the O-rings
The report, however, absolved the Reagan administration and
top NASA officials of blame, claiming they were never informed
of the concerns of engineers about the safety of the launch. Instead,
the commission singled out for blame several mid-level NASA officials
at the Marshall Space Flight Center.
Rogers pressured committee members, in particular Feynman,
to tone down the language of the report. Feynman had written a
scathing assessment of NASA managements procedure for risk
evaluation. He ridiculed NASAs claim that the probability
of shuttle failure was 1-in-100,000, saying this number was chosen
arbitrarily to make the program look safe, when the real probability
of failure was 1-in-50 or 1-in -100.
He wrote: Finally, if we are to replace standard numerical
probability usage with engineering judgment, why do we find such
an enormous disparity between the management estimate and the
judgment of engineers? It would appear that, for whatever purpose,
be it for internal or external consumption, the management of
NASA exaggerates the reliability of its product, to the point
of fantasy. (2)
Many members of the commission were dissatisfied with the report.
It was clear that even if top NASA officials had not been directly
told of the problems, they had made it abundantly clear to subordinates
that they did not want to hear anything that would stop the launch.
When Senator Ernest Hollings asked commission members why they
had not questioned the White House about rumors that Reagan officials
intervened to demand no further delays, Rogers erupted. The
president said himself nothing like that happened. Theres
no evidence in this case. There isnt one scintilla!,
he shouted.
The destruction of the space shuttle Columbia expresses at
a higher stage the same pressures and contradictions that led
to the Challenger explosion. The space shuttle was originally
designed in the early 1970s, based on a compromise design aimed
at cutting costs. NASA has never been given the funds to upgrade
its space vehicles to 21st century technological standards. The
aging fleet of shuttle vehicles has been a disaster waiting to
happen for years.
Scientific investigation and the safety of the astronauts themselves
has taken a back seat to commercial interests and military needs.
The inquiry into the Columbia disaster promises to be even more
perfunctory than the Challenger commission. Even before the definite
cause of the accident has been established, calls are being raised
for an early resumption of shuttle launches.
The genuine scientific and technological promise of the space
program cannot be realized under conditions of its subordination
to the interests of the US financial elite, which sees the space
program primarily as a source of national aggrandizement, enhanced
military power and potential corporate profit.
As in every other sphere of economic, social and intellectual
life, the progressive development of space exploration is not
compatible with an economic system whose motive force is private
profit, not the needs of society as a whole.
Notes:
1. The Presidential Commission on the
Space Shuttle Challenger Accident Report, June 6, 1986 chapter
6
2. Ibid. Appendix F, Personal observations on the reliability
of the Shuttle
See Also:
The Columbia tragedy: NASA,
Congress, Bush ignored safety warnings
[4 February 2003]
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