rocket (triggered) lightning Re: [TowerTalk] Static grounding protection-experience

[Jim Lux]

From: <mcduffie at actcom.net>
To: <towertalk at contesting.com>
Sent: Sunday, March 21, 2004 4:53 PM
Subject: Re: [TowerTalk] Static grounding protection-experience


On Sun, 21 Mar 2004 18:20:41 -0600, <wcmoore at verizon.net> wrote:

> The discharge path followed the exhaust and the tv footage was awesome.

The model rockets actually trailed a fine wire that remained grounded as
the rocket rose, allowing the conductor to go right toward the source.

----

The rocket and wire research has been done both at Univ of Florida (Martin
Uman's shop) and at a lab in New Mexico (where there's also a lot of
lightning).  There has been a fair amount of back and forth in the
literature about whether lightning following a wire is the same as natural
lightning.  One of the big activities in Florida is studying the underground
effects of lightning impulses (all that stuff K1TTT described, for
instance).. fulgurites, etc.

At KSC, NASAs done a lot of work with forecasting lightning (do we launch,
or run for cover?) and they have a huge array of field sensors tied together
in a computer network.  I don't know that they're doing all that much from a
lightning protection standpoint (certainly, they are obssessive about  ESD
protection, for instance) other than the standard sort of thing: pointy
lightning rods (no brushes, hex symbols, etc.), the usual big cables from
rods to ground.  Various and sundry rockets have taken hits from lightning
on launch without huge problems.  It's the preliminary stages that are more
worrisome: fueling, installing pyro devices, etc.  The rocket is basically a
big conductive tube, after all.