OT: Failure to communicate? Genesis

S

Spehro Pefhany

Guest
http://www.mercurynews.com/mld/mercurynews/news/breaking_news/9932295.htm?1c

I wonder if this was actually a first-angle-projection vs.
third-angle-projection mixup..

"Investigators report a likely reason Genesis' chutes did not open was
a faulty design that had these switches improperly installed on a
circuit board."

http://www.nasa.gov/mission_pages/genesis/main/index.html
http://www.nasa.gov/images/content/66943main_g_switch_hires.jpg


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
On Sat, 16 Oct 2004 00:13:26 -0400, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:

http://www.mercurynews.com/mld/mercurynews/news/breaking_news/9932295.htm?1c

I wonder if this was actually a first-angle-projection vs.
third-angle-projection mixup..

"Investigators report a likely reason Genesis' chutes did not open was
a faulty design that had these switches improperly installed on a
circuit board."

http://www.nasa.gov/mission_pages/genesis/main/index.html
http://www.nasa.gov/images/content/66943main_g_switch_hires.jpg


Best regards,
Spehro Pefhany
Click to expand...
Incredible blunder!

Which brings up the more general question: why are so many parts
symmetric? There are three wrong ways to mount a TQFP, and only one
right one; at least a DIP had a 50% chance of being right.

John
 
On Sat, 16 Oct 2004 05:22:25 GMT, Fred Bloggs <nospam@nospam.com>
wrote:

John Larkin wrote:
On Sat, 16 Oct 2004 00:13:26 -0400, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:


http://www.mercurynews.com/mld/mercurynews/news/breaking_news/9932295.htm?1c

I wonder if this was actually a first-angle-projection vs.
third-angle-projection mixup..

"Investigators report a likely reason Genesis' chutes did not open was
a faulty design that had these switches improperly installed on a
circuit board."

http://www.nasa.gov/mission_pages/genesis/main/index.html
http://www.nasa.gov/images/content/66943main_g_switch_hires.jpg


Best regards,
Spehro Pefhany


Incredible blunder!

Which brings up the more general question: why are so many parts
symmetric?

That package isn't symmetric- only one end is flanged. They don't show
the circuit board- but it looks like a simple component outline in
silkscreen should have minimized the chances of reverse assembly.
Click to expand...

Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?

John
 
John Larkin wrote:
On Sat, 16 Oct 2004 05:22:25 GMT, Fred Bloggs <nospam@nospam.com
wrote:



John Larkin wrote:

On Sat, 16 Oct 2004 00:13:26 -0400, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:



http://www.mercurynews.com/mld/mercurynews/news/breaking_news/9932295.htm?1c

I wonder if this was actually a first-angle-projection vs.
third-angle-projection mixup..

"Investigators report a likely reason Genesis' chutes did not open was
a faulty design that had these switches improperly installed on a
circuit board."

http://www.nasa.gov/mission_pages/genesis/main/index.html
http://www.nasa.gov/images/content/66943main_g_switch_hires.jpg


Best regards,
Spehro Pefhany


Incredible blunder!

Which brings up the more general question: why are so many parts
symmetric?

That package isn't symmetric- only one end is flanged. They don't show
the circuit board- but it looks like a simple component outline in
silkscreen should have minimized the chances of reverse assembly.




Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?

John
Click to expand...
Well you launched into that symmetry thing like that was the problem- it
seemed to me like you need glasses or something.
 
On Fri, 15 Oct 2004 22:44:10 -0700, John Larkin wrote:

On Sat, 16 Oct 2004 05:22:25 GMT, Fred Bloggs <nospam@nospam.com
....
That package isn't symmetric- only one end is flanged. They don't show
the circuit board- but it looks like a simple component outline in
silkscreen should have minimized the chances of reverse assembly.



Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?

Well, that's simple. He hasn't made your game yet. ;-)
Click to expand...

Cheers!
Rich
 
On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:

John Larkin wrote:
On Sat, 16 Oct 2004 05:49:14 GMT, Fred Bloggs <nospam@nospam.com
wrote:



John Larkin wrote:

On Sat, 16 Oct 2004 05:22:25 GMT, Fred Bloggs <nospam@nospam.com
wrote:



John Larkin wrote:


On Sat, 16 Oct 2004 00:13:26 -0400, Spehro Pefhany
speffSNIP@interlogDOTyou.knowwhat> wrote:




http://www.mercurynews.com/mld/mercurynews/news/breaking_news/9932295.htm?1c

I wonder if this was actually a first-angle-projection vs.
third-angle-projection mixup..

"Investigators report a likely reason Genesis' chutes did not open was
a faulty design that had these switches improperly installed on a
circuit board."

http://www.nasa.gov/mission_pages/genesis/main/index.html
http://www.nasa.gov/images/content/66943main_g_switch_hires.jpg


Best regards,
Spehro Pefhany


Incredible blunder!

Which brings up the more general question: why are so many parts
symmetric?

That package isn't symmetric- only one end is flanged. They don't show
the circuit board- but it looks like a simple component outline in
silkscreen should have minimized the chances of reverse assembly.




Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?

John


Well you launched into that symmetry thing like that was the problem- it
seemed to me like you need glasses or something.


I do need glasses, at least to drive. Being nearsighted is a pretty
good adaptation for an engineer.

But why couldn't that part have two leads welded to the header on one
end? Then it couldn't be installed backwards, and would be more
stable, too. You'd think that a g-switch should be strapped down
better than those two dinky leads allow. And why do mechanical
engineers seem to prefer symmetric mounting hole patterns, so that
mechanical gadgets can be mounted wrong, too?

I always thought DIPs should have an asymmetric pin pattern, and be
numbered zigzag instead of around the chip.


John


What I want to know is how was it that the subassembly was not put
through a qualifying operational test. Are those particular g-switches
some kind of one-time operation deals or what was the problem- even if
that was the case it would still be possible to achieve a high level of
confidence of operation by sacrificial testing of representative
samples. Have these people ever heard of single-thread failure mechanisms.
Click to expand...
It is seldom necessary to quote an entire string of message replies that
are themselves quotes of entire strings of message replies simply to add a
single paragraph.

You said, "Have these people ever heard of single-thread failure
mechanisms." I suspect that's why they put *two* switches in the system.

Jim
 
On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:


Are those particular g-switches
some kind of one-time operation deals or what was the problem-
Click to expand...
They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

Jim
 
James Meyer wrote:
On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:



Are those particular g-switches
some kind of one-time operation deals or what was the problem-


They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

Jim
Click to expand...
They look some kind of mechanical thing where something internally
*snaps* permanently. The orientation of g for takeoff and landing is
different obviously. You do know that g is a vector?
 
James Meyer wrote:
On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:



Are those particular g-switches
some kind of one-time operation deals or what was the problem-


They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

Jim
Click to expand...
Look at this: http://fy.chalmers.se/subatom/f2bmm/aep/CO4020.pdf
 
James Meyer wrote:

-- snip --

It is seldom necessary to quote an entire string of message replies that
are themselves quotes of entire strings of message replies simply to add a
single paragraph.

Then why'd _you_ do it?
Click to expand...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:s3d1n011anj2n2npgq60b20th0b394fhd8@4ax.com...
Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?
Click to expand...
One of my neighbors had a small dog like that when I was a kid. I threw a
big rock at it and then it left me alone.
 
Tom Del Rosso wrote:
"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:s3d1n011anj2n2npgq60b20th0b394fhd8@4ax.com...

Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?


One of my neighbors had a small dog like that when I was a kid. I threw a
big rock at it and then it left me alone.
Click to expand...
Whatever- you pro-Bush people are so damned ignorant- throwing a rock is
about the only option you have left.
 
On Sat, 16 Oct 2004 18:24:25 GMT, Fred Bloggs <nospam@nospam.com> wroth:

James Meyer wrote:

They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

Jim



They look some kind of mechanical thing where something internally
*snaps* permanently. The orientation of g for takeoff and landing is
different obviously. You do know that g is a vector?
Click to expand...
Of course G is a vector. How can you be sure that the vector, relative
to the switch, is different for takeoff and re-entry? What about the vector at
engine cut off? That would be 180 degrees from the takeoff vector. surely one
of them would be the same as the deceleration vector for re-entry.

The switch appears to be a cylinder with one lead attached to one end
and another lead entering the other end. How can you conclude that something
snaps permanently from such meager evidence?

Jim
 
On Sat, 16 Oct 2004 18:34:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:

Look at this: http://fy.chalmers.se/subatom/f2bmm/aep/CO4020.pdf
Click to expand...
What's a NIMBIN logic assembly got to do with G switches?

Jim
 
On Sat, 16 Oct 2004 11:40:18 -0700, Tim Wescott <tim@wescottnospamdesign.com>
wroth:

James Meyer wrote:

-- snip --



It is seldom necessary to quote an entire string of message replies that
are themselves quotes of entire strings of message replies simply to add a
single paragraph.

Then why'd _you_ do it?
Click to expand...
To illustrate my point. It was either that, or take my hat off.

Jim
 
James Meyer wrote:
On Sat, 16 Oct 2004 18:34:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:


Look at this: http://fy.chalmers.se/subatom/f2bmm/aep/CO4020.pdf


What's a NIMBIN logic assembly got to do with G switches?

Jim
Click to expand...
You tell me.
 
James Meyer wrote:
On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:

Are those particular g-switches
some kind of one-time operation deals or what was the problem-

They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.
Click to expand...
I was wondering about how many of these kind of components would survive
the UPS guy dropping the package, never mind the launch.

--
Paul Hovnanian mailto:paul@Hovnanian.com
------------------------------------------------------------------
Bumper sticker: You're too close for missiles. Switching to guns.
 
On Sun, 17 Oct 2004 17:35:16 -0700, "Paul Hovnanian P.E." <Paul@Hovnanian.com>
wroth:

James Meyer wrote:

On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:

Are those particular g-switches
some kind of one-time operation deals or what was the problem-

They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

I was wondering about how many of these kind of components would survive
the UPS guy dropping the package, never mind the launch.
Click to expand...
What kind of component do you think was used for the G switch aboard
Genesis? Was it a linear accelerometer driving a comparator, or a switch that
activated over a specific G value, or a one-time device that opened or closed at
a particular G value and then never worked again?

Jim
 
On Sat, 16 Oct 2004 10:15:58 GMT, Rich Grise <rich@example.net> wrote:

On Fri, 15 Oct 2004 22:44:10 -0700, John Larkin wrote:

On Sat, 16 Oct 2004 05:22:25 GMT, Fred Bloggs <nospam@nospam.com
...
That package isn't symmetric- only one end is flanged. They don't show
the circuit board- but it looks like a simple component outline in
silkscreen should have minimized the chances of reverse assembly.



Geez, Fred, I didn't say that package was symmetric (although it is
obviously easy to mount backwards.) I introduced a "general question."
Why do you follow me around, biting at my ankles?

Well, that's simple. He hasn't made your game yet. ;-)
Click to expand...
Hell, he won't even play.

John
 
James Meyer wrote:
On Sun, 17 Oct 2004 17:35:16 -0700, "Paul Hovnanian P.E." <Paul@Hovnanian.com
wroth:

James Meyer wrote:

On Sat, 16 Oct 2004 16:03:09 GMT, Fred Bloggs <nospam@nospam.com> wroth:

Are those particular g-switches
some kind of one-time operation deals or what was the problem-

They're G switches for goodness sakes. They *can't* be one-time deals.
What do you think they are subjected to during launch? You get three guesses
and the first two don't count.

I was wondering about how many of these kind of components would survive
the UPS guy dropping the package, never mind the launch.


What kind of component do you think was used for the G switch aboard
Genesis? Was it a linear accelerometer driving a comparator, or a switch that
activated over a specific G value, or a one-time device that opened or closed at
a particular G value and then never worked again?
Click to expand...
After reading up on the system, it appear as though Genesis used the
linear type accelerometers rather than threshold switches or one-time
devices.

I was addressing the problems inherent in the use of one-time devices as
some of the other posters had theorized they might be.

--
Paul Hovnanian mailto:paul@Hovnanian.com
------------------------------------------------------------------
Have gnu, will travel.
 
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