------ Original Message ------ Date: Fri, 17 Jun 2016 14:16:19 -0400 From: Robert McGwier rwmcgwier@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@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@eaglecreekobservatory.org To: amsat-bb@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