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Fw: AO-40 launched with "known problems" ??




----- Original Message -----
From: Jose Mihotel <jmihotek@gte.net>
To: John P. Toscano <tosca005@tc.umn.edu>
Sent: Monday, December 18, 2000 12:57 AM
Subject: Re: [amsat-bb] AO-40 launched with "known problems" ??


> John
>
> I think what Kevin means is you dont fly a missio  with a repaired
defective
> part. You replace it. For example, I ride a motorcycle. If I get a flat
tire
> due to a nail puncturing  the tire ( I use Tubeless tires), I dont repair
> it. I replace it and throw the old one away. You cannot skimp on tires,
> especially on a motorcycle and if you ride at high speeds.
> By the same token, I cannot justify flying a mission into space with a
> repaired thruster valve. It should have been replaced with a brand new
one.
> You cannot skimp on thruster valves in the satellite bussiness. If you do,
> you end up with an un-planned trajectory correction maneuver (TCM)
> consequence of  too much Delta V which is a consequence of a sticky
thruster
> motor valve.
>
> On another subject, the idea of a Ham satellite on a geostationary
injection
> orbit is very interesting due to the fact that no TCMs (Trajectory
> CorrectionManeuvers) are required and therefore no Thruster Motor, no
> propellant tanks, no Valves, etc... are needed. Remember that TCMs are a
> mission controller''a best friend and worst ennemy. They give the mission
> designer control over the spacecrafts route and the power to adjust errors
> in it's course. But if they don;t go just right--engine burns are timed
down
> to the second__they can introduce new errors in the trajectory. And each
> burn presents one more opportunity for something to go wrong, weather it
is
> a fuel line breaking, a valve sticking,or a tank exploding. Every time you
> enable the thrusters you are taking a chance.
>     So letting the Pros (Ariane) take care of all the maneuvering for us
> reduces the risks remendously and also reduces the cost and complexity a
> great deal.
>
> Respectfully
>
> Jose Mihotek
> KF4VND
>
>
>
>
> ----- Original Message -----
> From: John P. Toscano <tosca005@tc.umn.edu>
> To: 'amsat-bb' <amsat-bb@AMSAT.Org>
> Sent: Sunday, December 17, 2000 10:45 PM
> Subject: Re: [amsat-bb] AO-40 launched with "known problems" ??
>
>
> > Kevin Muenzler WB5RUE wrote:
> >
> > > But you'd think that something like this would have not been sent
> > > up with known problems.  Especially something like a fuel control
> > > valve that failed during testing.  I guess enough bending and
> > > hammering got it to work for the test.  They called it "nominal"
> > > which I guess was enough for the "stock holders" (YOU AND ME.)
> > >
> > > http://www.amsat.org/amsat/news/ans2000/ans00348.html
> >
> > Kevin, I'm confused.  I looked at the URL you provided, and THIS is
> > what caught my eye:
> >
> >   "We experienced a similar problem during the test phase of
> >    P3D, and one of the helium valves was repaired as a
> >    consequence."
> >
> > In case it isn't clear to you why this caught my eye, let me repeat
> > a part of that quote with a little emphasis:
> >
> >    "...and one of the helium valves WAS REPAIRED"
> >
> > The bird was tested.  A part failed.  It was repaired.  And you
> > consider that "...sending it up with a known problem..." ??????
> >
> > A lot of parts failed during testing.  AFIK, all the known problems
> > were fixed before launch.  What evidence do you have that the bird
> > was launched with any "known problems"?
> >
> > Or are you taking the position that because a part failed, such a part
> > must never be used again, or that the flight should never occur?
> > That's kind of like saying that rubber automobile tires are known to
> > occasionally fail, and failure sometimes leads to serious injury or
> > death of the driver or passengers.  Therefore all automobile
> > manufacturers must immediately stop building cars that depend on the
> > defective technology of pneumatic rubber tires.   Seeeshh!!!!!!
> >
> > Nomex underwear donned.
> > Environmental biohazard suit donned.
> > Asbestos lining donned.
> > Tyvek bulletproof body armor donned.
> > Fire control team outer flame suit donned.
> > Phasers on maximum.
> > Shields at 100%
> > Go ahead, make my day!
> >
> > Signed,
> > Tired of the whining in EN34
> > (a/k/a KBØZEV)
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

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