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"Everyone should have known"...



 
 
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  #1  
Old July 24th 03, 02:39 AM
Doug...
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Default "Everyone should have known"...

That's a phrase we hear a lot today -- that "everyone should have known"
about safety issues, about the fragility of the RCC, about risks that
should never be taken.

I was just reading the Apollo 17 mission requirements document, and saw
something I've seen before. Mission planning for EVAs was constrained
based on walkback in the case of a Rover failure or return to the LM in
case of a PLSS failure. The simultaneous occurrence of a PLSS and Rover
failure was specifically excluded from consideration.

But, think about it. What would be the most likely cause of a PLSS
failure? I'd think the most likely cause for a PLSS that had been
working perfectly to fail at any considerable distance from the LM would
be a catastrophic Rover accident. Say, the Rover hit a large rock at its
maximum speed that destroyed one front wheel assembly, flipped the
vehicle, and damaged one of the crew's PLSSes.

If that had happened on any of the J missions, and one or both of the
crew had died in the attempt to get back to the LM, "everyone should have
known" that a Rover accident was the most likely cause of a PLSS failure.
Right?

And yet, had the double failure situation been planned for and EVAs
limited to them, we would have been robbed of a great bounty of
exploration.

I guess all I'm saying is that risk is not *always* unwarranted. And
when you become unwilling to take *any* risks, you cease even trying to
accomplish great things.

--

It's not the pace of life I mind; | Doug Van Dorn
it's the sudden stop at the end... |
  #2  
Old July 24th 03, 04:15 AM
MasterShrink
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Default "Everyone should have known"...


That's a phrase we hear a lot today -- that "everyone should have known"
about safety issues, about the fragility of the RCC, about risks that
should never be taken.


People love hind-sight...it makes them feel smarter. When looking at history
you have to turn hind-sight off and put yourself in the position of what things
were like at the time.

It's easy to simply say "NASA was stupid" with the RCC matter. It's another
matter to step back and note why NASA felt comfortable with the RCC. If it
seems NASA really did have a reason to worry about the RCC's then they were
stupid...but considering in 111 successful flights concern was never voiced
before about the RCC why would they worry? The same with the record of foam
strikes. This, in my mind is an accident that was a long time coming because of
the shuttle's design...if you followed the rules...you were still screwed.

Not the same as STS 51-L where launching with ice hanging off the shuttle stack
was against the mission rules...and considering some (like John Young) were
quoted as saying "we're going to kill someone if we keep flying like this" I
can say "this was an accident that was avoidable if you just followed the
rules."

The J mission scenario you just mentioned...yeah, its a good possiblity.
However if you take into account the idea of a PLSS and Rover failure then you
really have no point for including the Rover on the J-Missions. There is a
point where you just have to hope to God your gear works okay.

-A.L.
  #3  
Old July 24th 03, 10:21 AM
OM
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Default "Everyone should have known"...

On Wed, 23 Jul 2003 20:39:37 -0500, Doug...
wrote:

If that had happened on any of the J missions, and one or both of the
crew had died in the attempt to get back to the LM, "everyone should have
known" that a Rover accident was the most likely cause of a PLSS failure.
Right?


....Considering the number of Astronauts who were reckless car crazies
back in those day, it honestly would have come as no surprise.


OM

--

"No ******* ever won a war by dying for | http://www.io.com/~o_m
his country. He won it by making the other | Sergeant-At-Arms
poor dumb ******* die for his country." | Human O-Ring Society

- General George S. Patton, Jr
  #4  
Old July 24th 03, 02:04 PM
Herb Schaltegger
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Default "Everyone should have known"...

In article ,
(MasterShrink) wrote:

The J mission scenario you just mentioned...yeah, its a good possiblity.
However if you take into account the idea of a PLSS and Rover failure then you
really have no point for including the Rover on the J-Missions. There is a
point where you just have to hope to God your gear works okay.


It's the same calculus used by people every day in every walk of life
for tasks ranging from the relatively mundane (like say hoping your car
doesn't break down crossing Death Valley in July) to out of the ordinary
(not carrying a pony bottle on a 110' wreck dive - most people don't -
and presuming your first stage won't fail because it never has before
and it's recently been checked out anyway) to the completely extreme
(sheer face cliff climbers who have to rely on their ropes, pitons,
carabiners and so forth to work as designed).

As I've posted before, part of ANY kind of living requires you to know
the risks you're facing, know the gray areas (i.e., generally understand
the limits of your knowledge), then make informed decisions as to
whether the benefits outweigh the risks, as informed by the known limits
of your own knowledge. As regards Columbia, for instance, it appears
the MMT failed to comprehend the limits of their own knowledge.

--
Herb Schaltegger, Esq.
Chief Counsel, Human O-Ring Society
"I was promised flying cars! Where are the flying cars?!"
~ Avery Brooks
  #5  
Old July 24th 03, 03:37 PM
Reivilo Snuved
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Default "Everyone should have known"...

Herb Schaltegger writes:

It's the same calculus used by people every day in every walk of life
for tasks ranging from the relatively mundane (like say hoping your car
doesn't break down crossing Death Valley in July) to out of the ordinary
(not carrying a pony bottle on a 110' wreck dive - most people don't -
and presuming your first stage won't fail because it never has before
and it's recently been checked out anyway)


110' ? bah ... 220' now you're talking.
  #6  
Old July 24th 03, 04:13 PM
Herb Schaltegger
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Default "Everyone should have known"...

In article , Reivilo Snuved
wrote:

Herb Schaltegger writes:

It's the same calculus used by people every day in every walk of life
for tasks ranging from the relatively mundane (like say hoping your car
doesn't break down crossing Death Valley in July) to out of the ordinary
(not carrying a pony bottle on a 110' wreck dive - most people don't -
and presuming your first stage won't fail because it never has before
and it's recently been checked out anyway)


110' ? bah ... 220' now you're talking.


220'? Not without a buddy I am VERY confident in, dual tanks, a pony
bottle, three dive computers (two-fault tolerance!) and a couple of
decompression stages with tanks, thankyouverymuch! Oh, yeah - and a
fully-staffed chamber within a mile of the dock, just in case.

--
Herb Schaltegger, Esq.
Chief Counsel, Human O-Ring Society
"I was promised flying cars! Where are the flying cars?!"
~ Avery Brooks
  #7  
Old July 25th 03, 05:07 PM
Jay Windley
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Default "Everyone should have known"...


"Doug..." wrote in message
...
| That's a phrase we hear a lot today -- that "everyone should
| have known" about safety issues, about the fragility of the RCC,
| about risks that should never be taken.

This is always the pitfall of hindsight in failure analysis. The people who
argue that someone "should have known" something have the luxury of looking
at the evidence knowing that something failed, and of looking at a
pared-down collection of evidence. Those without the luxury of hindsight
have no way of acquiring this incisive perspective. They do not know ahead
of time that something *will* fail and hence that they should pay close
attention to certain then-innocuous indications. Further, they have the
whole pot of data from every aspect of the system to look at -- among which
may certainly be evidence of impending failure; but there won't be a
flashing light giving artificial salience to that data.

The notion that the potential of mixed-mode or collaborative failures can be
exhaustively predicted for complex systems is simply daft. This was studied
in the wake of the Apollo 13 accident. In a complex system you can discover
single points of failure, and perhaps combinations of two points of failure.
But you cannot exhaustively consider all potential n-way causes of failure.

When we say space travel is inherently dangerous, this is what we mean.

--
|
The universe is not required to conform | Jay Windley
to the expectations of the ignorant. | webmaster @ clavius.org

 




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