7 myths about the Challenger shuttle disaster

More space/science/tech talk.

The most interesting part of this article for me was the discussion of how
long the crew may have lived. I've heard different things over the years
living among the folks who work at Johnson but no one talks much about it.
I'm not sure if that's because the facts were never published widely (as far
as I know) or folks just didn't want to talk. I had never heard that they
found used air tanks before so that certainly indicates his assumptions that
the crew didn't die immediately are correct. I was also glad to see he
cleared up all this business about an 'explosion'



JH




7 myths about the Challenger shuttle disaster
It didn't explode, the crew didn't die instantly and it wasn't inevitable

By James Oberg
NBC News space analyst
Special to MSNBC
Updated: 11:39 p.m. ET Jan. 25, 2006


HOUSTON - Twenty years ago, millions of television viewers were horrified to
witness the live broadcast of the space shuttle Challenger exploding 73
seconds into flight, ending the lives of the seven astronauts on board. And
they were equally horrified to learn in the aftermath of the disaster that
the faulty design had been chosen by NASA to satisfy powerful politicians
who had demanded the mission be launched, even under unsafe conditions.
Meanwhile, a major factor in the disaster was that NASA had been ordered to
use a weaker sealant for environmental reasons. Finally, 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.

At least, that seems to be how many people remember it, in whole or in part.
That's how the story of the Challenger is often retold, in oral tradition
and broadcast news, in public speeches and in private conversations and all
around the Internet. But spaceflight historians believe that each element of
the opening paragraph is factually untrue or at best extremely dubious. They
are myths, undeserving of popular belief and unworthy of being repeated at
every anniversary of the disaster.

The flight, and the lost crewmembers, deserve proper recognition and
authentic commemoration. Historians, reporters, and every citizen need to
take the time this week to remember what really happened, and especially to
make sure their memories are as close as humanly possible to what really did
happen.

If that happens, here's the way the mission may be remembered:

a.. Few people actually saw the Challenger tragedy unfold live on
television.
a.. The shuttle did not explode in the common definition of that word.
a.. The flight, and the astronauts' lives, did not end at that point, 73
seconds after launch.
a.. The design of the booster, while possessing flaws subject to
improvement, was neither especially dangerous if operated properly, nor the
result of political interference.
a.. Replacement of the original asbestos-bearing putty in the booster seals
was unrelated to the failure.
a.. There were pressures on the flight schedule, but none of any
recognizable political origin.
a.. Rationalizations that the disaster was the unavoidable price to be paid
for pioneering a new frontier were self-serving cover-ups of those
responsible for incompetent engineering management - the disaster should
have been avoidable.
Myth #1: A nation watched as tragedy unfolded
Few people actually saw what happened live on television. The flight
occurred during the early years of cable news, and although CNN was indeed
carrying the launch when the shuttle was destroyed, all major broadcast
stations had cut away - only to quickly return with taped relays. With
Christa McAuliffe set to be the first teacher in space, NASA had arranged a
satellite broadcast of the full mission into television sets in many
schools, but the general public did not have access to this unless they were
one of the then-few people with satellite dishes. What most people recall as
a "live broadcast" was actually the taped replay broadcast soon after the
event.

Myth #2: Challenger exploded
The shuttle did not explode in the common definition of that word. There was
no shock wave, no detonation, no "bang" - viewers on the ground just heard
the roar of the engines stop as the shuttle's fuel tank tore apart, spilling
liquid oxygen and hydrogen which formed a huge fireball at an altitude of
46,000 ft. (Some television documentaries later added the sound of an
explosion to these images.) But both solid-fuel strap-on boosters climbed up
out of the cloud, still firing and unharmed by any explosion. Challenger
itself was torn apart as it was flung free of the other rocket components
and turned broadside into the Mach 2 airstream. Individual propellant tanks
were seen exploding - but by then, the spacecraft was already in pieces.


Myth #3: The crew died instantly
The flight, and the astronauts' lives, did not end at that point, 73 seconds
after launch. After Challenger was torn apart, the pieces continued upward
from their own momentum, reaching a peak altitude of 65,000 ft before
arching back down into the water. The cabin hit the surface 2 minutes and 45
seconds after breakup, and all investigations indicate the crew was still
alive until then.

What's less clear is whether they were conscious. If the cabin depressurized
(as seems likely), the crew would have had difficulty breathing. In the
words of the final report by fellow astronauts, the crew "possibly but not
certainly lost consciousness", even though a few of the emergency air
bottles (designed for escape from a smoking vehicle on the ground) had been
activated.

The cabin hit the water at a speed greater than 200 mph, resulting in a
force of about 200 G's - crushing the structure and destroying everything
inside. If the crew did lose consciousness (and the cabin may have been
sufficiently intact to hold enough air long enough to prevent this), it's
unknown if they would have regained it as the air thickened during the last
seconds of the fall. Official NASA commemorations of "Challenger's 73-second
flight" subtly deflect attention from what was happened in the almost three
minutes of flight (and life) remaining AFTER the breakup.

Myth #4: Dangerous booster flaws result of meddling
The side-mounted booster rockets, which help propel the shuttle at launch
then drop off during ascent, did possess flaws subject to improvement. But
these flaws were neither especially dangerous if operated properly, nor the
result of political interference.

Each of the pair of solid-fuel boosters was made from four separate segments
that bolted end-to-end-to-end together, and flame escaping from one of the
interfaces was what destroyed the shuttle. Although the obvious solution of
making the boosters of one long segment (instead of four short ones) was
later suggested, long solid fuel boosters have problems with safe propellant
loading, with transport, and with stacking for launch - and multi-segment
solids had had a good track record with the Titan-3 military satellite
program. The winning contractor was located in Utah, the home state of a
powerful Republican senator, but the company also had the strengths the NASA
selection board was looking for. The segment interface was tricky and
engineers kept tweaking the design to respond to flight anomalies, but when
operated within tested environmental conditions, the equipment had been
performing adequately.

Myth #5: Environmental ban led to weaker sealant
A favorite of the Internet, this myth states that a major factor in the
disaster was that NASA had been ordered by regulatory agencies to abandon a
working pressure sealant because it contained too much asbestos, and use a
weaker replacement. But the replacement of the seal was unrelated to the
disaster - and occurred prior to any environmental ban.

Even the original putty had persistent sealing problems, and after it was
replaced by another putty that also contained asbestos, the higher level of
breaches was connected not to the putty itself, but to a new test procedure
being used. "We discovered that it was this leak check which was a likely
cause of the dangerous bubbles in the putty that I had heard about," wrote
physicist Richard Feynman, a member of the Challenger investigation board.

And the bubble effect was unconnected with the actual seal violation that
would ultimately doom Challenger and its crew. The cause was an inadequate
low-temperature performance of the O-ring seal itself, which had not been
replaced.

Myth #6: Political pressure forced the launch
There were pressures on the flight schedule, but none of any recognizable
political origin. Launch officials clearly felt pressure to get the mission
off after repeated delays, and they were embarrassed by repeated mockery on
the television news of previous scrubs, but the driving factor in their
minds seems to have been two shuttle-launched planetary probes. The first
ever probes of this kind, they had an unmovable launch window just four
months in the future. The persistent rumor that the White House had ordered
the flight to proceed in order to spice up President Reagan's scheduled
State of the Union address seems based on political motivations, not any
direct testimony or other first-hand evidence. Feynman personally checked
out the rumor and never found any substantiation. If Challenger's flight had
gone according to plan, the crew would have been asleep at the time of
Reagan's speech, and no communications links had been set up.

Myth #7: An unavoidable price for progress
Rationalizations that the disaster was the unavoidable price to be paid for
pioneering a new frontier were self-serving cover-ups of those responsible
for incompetent engineering management - the disaster should have been
avoidable. NASA managers made a bad call for the launch decision, and
engineers who had qualms about the O-rings were bullied or bamboozled into
acquiescence. The skeptics' argument that launching with record cold
temperatures is valid, but it probably was not argued as persuasively as it
might have been, in hindsight. If launched on a warmer day, with gentler
high-altitude winds, there's every reason to suppose the flight would have
been successful and the troublesome seal design (which already had the
attention of designers) would have been modified at a pace that turned out
to have been far too leisurely. The disaster need never have happened if
managers and workers had clung to known principles of safely operating on
the edge of extreme hazards - nothing was learned by the disaster that
hadn't
already been learned, and then forgotten.



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