Not sure where you heard that, Hal. I can't imagine a rad-hard
flight qualified IC of any kind costing $1.79. Maybe a flight
machine screw, but not a rad-hard IC. I know a retired propulsion
engineer who worked on the MO accident investigation. He told
me that it was most likely the poor thermal design of the propulsion
system which was a design originally intended for earth orbit. The
contractor who built it failed to fully account for the effects of the
colder environment that would be encountered on a long trip to
Mars. The freezing cold lines may allowed the oxidizer to leak
past a check valve into the fuel line which in turned caused the line
rupture. This is listed as the most likely cause of the accident by
the accident review board. The squib from the pyro is listed in the
accident report as another possible cause, but not because it fired
out of sequence, but because it ejected debris which hit the fuel
tank and caused it to rupture:
http://nssdc.gsfc.nasa.gov/planetary/text/marsob.txt
The only mention of the C&DH was with regard to possible
single point component failure vulnerability - no specifics.
Nobody who builds space hardware would bat an eye at spending
an extra $.50 for an IC. Usually it comes down to whether or not
you to spend $20,000 or $100,000 dollars to qualify and screen
a particular part for high-rel duty.
73 de Mike, W4EF............................................
----- Original Message -----
From: "Harold B. Mandel" <ka1xo@juno.com>
To: <wa7fab@cdsnet.net>
Cc: <craxd1@verizon.net>; <amps@contesting.com>
Sent: Thursday, July 28, 2005 3:34 PM
Subject: Re: [Amps] NASA Workmanship Standards
> Remember the Mars Observer spacecraft?
>
> $845,000,000.00 budget.
>
> The housekeeping CPU team opted for $1.29 a piece
> CMOS chips instead of the titanium-armored kind that
> was bid at $1.79 a piece.
>
> 1 stray chunk of particulate radiation went through
> one particular chip and the rocket motor fuel
> pump pressurized before the vent opened,
> and then the squib fired.
> Ooops! (Boom!)
>
> Hal Mandel, W4HBM
>
> On Wed, 27 Jul 2005 18:55:12 -0700 "Van K7VS" <wa7fab@cdsnet.net> writes:
>> Considering the problems with the current launch and flight of the
>> Space
>> Shuttle, think I will look elsewhere!
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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