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Re: Re: Funny old satellite design



The Soviet designers did use nitrogen pressurized enclosures as you suggested,
you can see these in their early spacecraft designs. US rockets were not as
powerful as Russian rockets in the early days, so such a brute force design
was not available to US spacecraft designers. Some early space vehicles did
have thermal problems until they learned to get their paint patterns right.
Today we mostly trust the computer models.

Electronic modules were often constructed "cordwood style", where small PCBs
were fabricated and each resistor or capacitor were stacked like firewood with
axial leads soldered to a separate PCB at each end.

James Van Allen worked at the Applied Physics Laboratory in Maryland during
WWII, where the proximity fuze work was mostly done. He had a fresh PhD from
the University of Iowa which also played a role in developing this fuze.
Basically the fuze was a crude radar device, which sent out an RF signal and
detected its reflection when it was in the proximity of an enemy aircraft,
allowing anti-aircraft shells to hit their targets with much greater accuracy.
Their research group did a lot of work to develop small vacuum tubes that
could withstand being shot from an artillery gun. After the war Van Allen
returned to Iowa where he started a program to measure cosmic rays using
sounding rockets fired from navy ships mostly in polar areas. When the space
program began, his experience in building electronic circuits that could
survive being fired from a gun was very helpful is designing the first
satellite payloads to ride on top of the Vanguard or the Jupiter rockets. He
wisely designed his cosmic ray instrument so that it would fit inside either
satellite design, so that when the first Vanguard launch failed his was just
about the only science payload that was ready to go on the Explorer satellite.
This of course lead to the discovery of what would eventually be known as the
Van Allen belts.

You can read all about this in his book "Origins of Magnetospheric Physics",
Smithsonian Institution Press, Washington DC, 1983.

Dan Schultz N8FGV

----------------------------------------------------------------------------------------
William Leijenaar wrote:

>I forgot to ask something what I noticed when I saw this very old satellite 
>design.

>I wondered if they kept the inside of the football shape full of air ?
>In those days they had no experience with temperature, radiation, vaccuum 
>etc...
>So propably to avoid problems they might have choosen to keep the components

>under earth-air-pressure...

>I also noticed that they didn't use any kind of PCB, or structure to hold 
>the components.
>I would say all components would be "pressed" down due to the high G-force 
>of the rocket...


Assi Friedman wrote:

>PCBs were invented in WW-II for the "top secret" proximity detonators used
>on anti-aircraft shells for the pacific theater. The small group (including
>a ham radio operator) designed and built the electronic detonator using the
>standard chassis construction technique, but the tight volume limitations
>did not allow that luxury. As a result, they invented a plate drilled with
>holes with the conductors on the bottom and components on top. Initially, it
>was a printed wiring board, and now days its a printed circuit board. I
>don't know in which decade the PWB became common place in the commercial
>world, but I am not surprised that it wasn't used extensively in the 1950s.





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