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Re: Right-sizing a sat [was: Antennas on the bird]



on 1/12/01 6:46 PM, Robert Oler at cvn65vf94@msn.com wrote:

>> we
>> should have had more AO-10/13 types.  Well, AO-10's computer is dead and
>> AO-13 was vaporized.  While we learned from these, what's to make us think
>> that bad things wouldn't happen to birds in the future.
>> 
> 
> What killed A0-10's computer and the orbital mechanics that tossed 13 into
> the autmosphere are well understood now (and I think that AO-10's rad
> problem was well understood to...I just dont think that they could get a
> better 1802) and have nothing really to do with the size of the satellite or
> the magnitude of the program....or really my comments.

Of course they are known now.  And we now will know more about designing
better propulsion systems.

A new AO-40 could be built in far less time than the current one.  It's
called the learning curve.

At the same time, I don't know if those of us talented enough to build
satellites would want to spend all their time building bird after bird of
the AO-10 or AO-13 variety.  I think they'd like to take a rest from their
work and enjoy USING the birds instead of constantly building them.  And
then as far as launches go, it probably doesn't cost that much different to
launch an AO-40 size bird vs. an AO-13 sized bird (just a guess but we
certainly don't have resources to afford many, many launches, IMHO).

Then there is QRM issues we'd have to worry about.  If we build more
AO-10/13 types with primarily mode B and mode J transponders (I think this
is what you were sort of getting at), what happens when their orbits overlap
for periods of time?  If we have four or five P3C class satellites in orbit,
it would be pretty impractical to use 2m, at least, as a satellite band.  We
could have handled a semi-working AO-10 and AO-40, but multiple birds
wouldn't work.  You'd have to go to UHF, microwave and higher.  And if you
have 3 birds accessible to you which one do you use?  Would their
transponders overlap in frequency?  If so, what would happen then? etc...
Not insurmountable problems perhaps, but a different set.

Oh well, enough rambling....

Anyhow, I think the AO-40 concept is great and I would support another such
bird.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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