[TowerTalk] spider balls.. they work

[Jim Lux]

A
>How can lightning risk management be anything more than subjective views 
>and marketing?

By using properly validated and objective testing.  If the manufacturer 
wanted to prove that their devices work, they could set up two identical 
towers in an area with lots of thunderstorms and lightning.  Place the 
widget at the top of one.  Observe lightning statistics for some 
time.  Switch the widget to the other one.  Observe the statistics.  repeat 
a bunch of times.

The equipment and labor to do this would cost maybe 10 thousand bucks, and 
I'll bet they could find somewhere to set up that wouldn't charge them. 
They could certainly find grad students to do the actual work of recording 
statistics and doing analysis for almost free.  (In fact, several of the 
IEEE authors have essentially volunteered for this!)

I note the manufacturers of these devices studiously avoid doing such 
tests, relying instead on testimonials and anecdotes.



>   My personal view is if mother nature wants to screw with anything man 
> made mother nature will have her way with ease.



>Regarding NASA, they bought the devices. They must have thought they would 
>work when they purchased the devices. Did NASA get snookered?  Maybe! 
>Maybe their expectations were marketed. Reducing the risk and eliminating 
>the risk are two very different things.

The level of approval for something this inexpensive is quite low.  I could 
easily see someone deciding that whether they work or not, it's cheaper 
just to buy them and try it, than it is to hold a series of meetings and do 
the analysis to determine whether they worked.

You'll note that the mfr claims NASA bought them, not that NASA said they 
worked.

>Also I seem to remember NASA saying on numerous occasions that the space 
>shuttle was safe, usually after each massive failure in safety.  How does 
>NASA define "safe"?

Now there's a huge can of worms!


>How does NASA define "works"?

Less of a can of worms. Presumably you'd have some objective standard of 
success or failure.  Example, the Mars Rover lasts 90 sols, takes so many 
pictures, moves so many meters, etc. and it is officially a success. (Hence 
terms like "Mission Success Panorama").