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RE: Cube vs Tube form




There are a few reasons for that:
1. Most amateur satellites use body mounted solar-cells. It is pretty hard to
epoxy solar-cells to a round shape. In addition, solar-strings that are
pointed in different angles need to be electrically isolated from each other
to prevent one string from dumping power into another. With the newer 3J GaAs
technology, reverse biasing of cells can cause junction failure and a loss of
a string. Thus, the designer has to make an optimization decision between
fewer panels, less favorable pointing angles, easier electrical configuration,
and more panels, more favorable pointing angles, and complex electrical
configuration.
2. Round is a shape that is hard to work with, PCB shops don't like cutting
round pcbs, and machinists give you the evil eye when you ask for a box.
ASUSat1 had 14 sides (what were we thinking?) and that approximated a round
shape. We had illumination on 5 panels at once and generated more power then
an equivalent square shape. But the wiring for that was hell, and the guts of
the bird were not fun to work with either.
If you look at modern designs, many go to a 6 sided structure, that provides a
good compromise between solar-panels and simplicity.
Assi 4x1kx/kk7kx


-----Original Message-----
From: Gustavo Carpignano [mailto:gus@gctelecomar.com]
Sent: Wednesday, April 25, 2001 1:40 PM
To: amsat-bb@AMSAT.Org
Subject: [amsat-bb] Cube vs Tube form


Hello,

Can someone explain the different between a cube and tube form in a
satellite body.

Why all hamsat have a cube form ?

regards.

Gustavo.




--------------------------------------------------------------
 Assi Friedman, ASUSat Program
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 Tel: 480-965-2859 (Office)
 Tel: 480-965-2474 (ASUsat lab)
 Fax: 480-965-0277 (ASUsat lab)
 Email: assib@asu.edu
 Home Page: http://www.public.asu.edu/~assib
 ASUSat Page: http://nasa.asu.edu
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