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Old February 3rd 17, 12:33 PM posted to sci.space.history
Jeff Findley[_6_]
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Default The Space Race was about Power Projection - Miles O'Brien

In article ,
says...
There are times when I think Usenet needs a 'Like' button...


I myself see a lot to be in wanting in Jeff's post.


JF: Imagine if you had two cars and had to pull the cylinder head from one and install it on the other when you wanted to use it. Insane, right?"

That is called "cannibalization", and a very common practice in high performance aerospace vehicles. Hardly ideal, but a cost-effective approach to maintenance.


Firstly, I believe in primary sources. Here is the best source when it
comes to the causes leading up to the Challenger disaster:

Report to the President
By the PRESIDENTIAL COMMISSION
On the Space Shuttle Challenger Accident
June 6th, 1986
Washington, D.C.
https://spaceflight.nasa.gov/outreac.../assets/rogers
_commission_report.pdf

Cannibalization is discussed on page 174 under the heading of "Effect of
Flight Rate on Spare Parts". This was *not* a good thing when parts
were being pulled after *every* flight.

JF: "the SRBs ought to have been replaced with reusable liquid boosters"

A fact that so many people are willing to ignore is that the SRBs performed totally adequately for 24 straight missions. They never failed a single time. So that's 48 SRB successes in a row. 144 field joints did their job.

The only time they failed was when NASA decided to launch with temps WAY OUT OF LIMITS. Here is an exact quote from Thiokol's Bob Ebeling:

"[W]e're only qualified to 40 degrees ...'what business does anyone even have thinking about 18 degrees, we're in no man's land.'"
(https://www.nasaspaceflight.com/2007...of-challenger/)

THAT is the one and only proximate cause of the Challenger disaster.


Actually, your thinking is pretty much exacly how middle management was
handing several different issues with the space shuttle system, any one
of which could have caused loss of orbiter and crew. The thinnking that
"we've gotten away with it for 24 missions, so there is no reason to
stop flying" is why Challenger happened. It's quite simply wrong headed
thinking to point to *one single cause* in cases like this. Several
things were wrong with the SRB field joint and several other systems in
the space shuttle were just as bad.

The fact of the matter is that the o-rings should never have come into
contact with combustion gasses and should never have experienced
erosion. While temperature did have a huge impact on the probability of
burn through, other factors (such as cases being out of round, joint
rotation when pressure built up, and the fatally flawed way the joints
o-ring seals were tested) could very well have caused a failure even
when flown at temperatures over 40 degrees.

Again, take a look at *all* of the systems which were modified and
upgraded during the downtime following Challenger. There were
*several*.

...and the culpability for this fatal error falls not only on
NASA top management, nor middle management, but the one level
of decision-making that everyone, for whatever reason, chooses
to avoid mentioning:

- Operations.

THEY were the ones whose duty was to know these limits better
than anyone else involved in the launch decision. Yet all of
them decided to not voice their objections. That goes for the
dozens upon dozens of people in Launch Control, the many
dozens in Mission Control, and also the crew themselves.

The crew paid for this mistake with their lives.
Other people in operations like Gene Thomas, Bob Sieck,
Jay Greene, Fred Gregory, etc got *promoted*.

That's the most effective way to cover up an egregious error.
Everybody pretend that it never happened. That it wasn't their
job to stop the launch. It's much easier to blame an inanimate
object like O-rings even though they had a track record of a
100% success rate when launched within temp limits.

SRB field joints had a batting average of 1000. 144 successes
with 144 at bats.

Not a perfect design, to be sure. But it worked when
established limits were respected.

O-rings are *NOT* what killed Scobee and his crew. It was
every person involved in the chain that arrived at the decision
that it was a good idea to launch in spite of the freezing
cold temps.


Yes the decision making was flawed. But even worse the culture was
flawed. The shuttle was flying with *several* systems which were quite
marginal and could lead to loss of the orbiter and the crew. It's not
that this *one* decision was wrong. That's far too simplistic.

And it likewise needs to be identified that also culpable for these
7 fatalities is everyone from back in the 1970s who was involved in
the decision to not give shuttle crews a viable means of escape.
It would have been very easy to have designed the crew cabin as a
breakaway structure. Being a pressure vessel, it was already
robust. Not much more was needed than a stabilization drogue
chute and thermal protection. A set of very light tiles or
blankets would have done the trick. From there, all the crews
would have needed was pressure suits with parachutes.


Agreed that the system was flawed in that it lacked a crew escape
capability on a vehicle that was large, complex, and prone to failure.
As for an escape capsule being a viable add-on to the shuttle, I call
bull****.

Look at the history of the F-111 and B-1A crew capsule escape systems.
Making such a system work while an aircraft is breaking apart is *very*
difficult. Making one work at "max-Q" during a shuttle launch (i.e.
when Challenger broke up due to aerodynamic forces) would have been even
harder. Making one work for a Columbia syle accident would mean the
escape capsule would have to be an actual reentry capsule with its own
heat sheild, reaction control system, parachutes, landing air bags, and
etc.

All of this would have added complexity, weight, and even additional
failure modes. Since the shuttle program was already not meeting its
payload goals, this could have resulted in a vehicle with a large
payload bay but little to no actual payload mass capability.

Such a simple low cost lightweight low-performance-impact solution
would have saved 14 lives. Or if it failed in saving lives, it
would have at least given them a fighting chance. Some glimmer
of hope for survival.


Except such a system would not have been lightweight, low cost, or even
highly reliable based on the long history of "escape capsules" on high
performance aircraft.


In the case of 51-L, something as simple as a sport parachute might
have made the difference between living and dying. This is *half*
of what recreational parachutists use on a daily basis. Just give
the astronauts the "reserve". But no. They were not even given
that much.


Which is why after Challenger the crews wore both pressure suits and the
shuttle was equipped with an escape pole.

But leaving in criticallity one failure points, like the flawed SRB
field joint, is still not a good idea. And again, that was not the only
criticallity one failure point addressed post Challenger. You're
glossing over details and that's never a good idea when the details
matter.


This has been discussed to death in the distant past. Why don't you re-
read the entire Rogers Commission Report on Challenger, the Columbia
Accident Investigation Report, and take a look at what modifications
were made to the space shuttle system after each of these accidents.
You'll find that it's not as simple as one failure point. Accident
investigations like this tend to uncover many failure points.

Jeff
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