[amsat-bb] Only Half of the CubeSats Deployed into Space Work

Daniel Schultz n8fgv at usa.net
Sun Jun 19 03:58:11 UTC 2016

------ Original Message ------
Date: Fri, 17 Jun 2016 14:16:19 -0400
From: Robert McGwier <rwmcgwier at gmail.com>

>Space is a mean nasty place.  Hard Vacuum, very energetic particles
>slamming you, micrometeorites and space junk clobbering, computers
>GUARANTEED to get into a failure mode, with probability 1.  And then what
>do you do?  Most don't know. Only experience tells you how not to have a
>dead computer or one acting in  a stupid way and how to fix it.

Without naming any names, many years ago I had some limited involvement with a
group that was going to build a satellite. Their transmitter was based on one
of the Motorola RF chips intended for the cordless telephone or baby monitor
market. They copied one of the example circuits from the manufacturer's data
sheet and designed it into their satellite, with no workbench prototype to see
if it actually works. There were no environmental tests, no thermal vacuum
test, no extended range temperature test, no "day in the life" test, no
vibration test. The satellite was delivered to the launch authority, which
successfully placed it into orbit, and it was never heard from after launch,
just another piece of space debris from day one. They were not interested in
hearing any advice from anybody, because they were the smartest students at
one of the best schools in the country, they had nothing to learn from
anybody. That is how you design for failure.

------ Original Message ------
Received: Fri, 17 Jun 2016 04:01:31 AM EDT
From: "Graham Shirville" <g.shirville at btinternet.com>
> Can we, collectively, come up with a better name than "Hobbyists" that 
> he shows in slide 3? 

In professor Swartwout's data base, AMSAT is not classified in the "Hobbyists"
category, he places us under the "Commercial" category. His use of "Hobbyists"
refers to people and organizations who are building their first satellite with
no prior experience and little access to previous knowledge. Many of these
organizations give up after one failure and are replaced by another
first-timer group, so that the failure rate among the "Hobbyists" group of
CubeSats is pretty much guaranteed to remain high. 

------ Original Message ------
Date: Fri, 17 Jun 2016 15:16:13 -0500
From: "Kevin Muenzler, WB5RUE" <kevin at eaglecreekobservatory.org>
To: <amsat-bb at amsat.org>

>Of course a few LEO Linear birds like the old RS-12/13 would be nice too!  I
>don't know how many hundreds of qsos I had on 2/10 using RS-12.  

When reminiscing about the Radio Sputnik satellites, keep in mind that these
were hosted payloads on a larger satellite, and they received a copious amount
of electrical power from the primary satellite. This is a sweet deal if you
can get it, but with the tiny little CubeSat form factors that we are forced
to use today, it will be difficult to match the performance that you remember
from the "good old days" of RS-12/13. 

73, Dan Schultz N8FGV

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