Hello members!
Well, as long as we are all trading emc horror stories I might as
well pitch in. I have a pretty good one.
Just before the launch of Apollo 11 [the first manned moon landing]
NASA discovered a big emc problem: something was causing the fuel cells of
the command module to short out at random. The command module is the capsule
that the astronauts rode in during launch, to the moon, & back.
This was bad news because you couldn't launch like that, and apollo
11 was already out on the pad, the press was arriving, and the whole world
was watching.
I was the youngest guy in a 5-man emc section that NASA had at the
Kennedy Space Center. A bunch of big-wigs came down from Washington, DC.
They told us ( i.e. my boss) to fix it. "Money is no object." they said. I,
who imagined myself to be a suave, sophisticated New Yorker, was stunned.
My jaw just dropped open. I had absolutely no idea how to do do this.
To complicate things, we were not allowed to disconnect any cables:
configuration control. So my boss, who was a really smart guy, had us build
a bunch of huge current probes. Some of them were about 5 ft in diameter. we
built two identical pairs of each probe. We set them up around big bundles
of cables, and set up a some receivers, timing receivers (clocks), and strip
chart recorders. With the help of a large group of contractors (ITT Federal
Electric Corp.) we monitored those probes 24 hours a day. Whenever the
problem occurred, we ran to the strip charts to see if anything funny had
happened in the bundle at that same time. We found time-coincident glitches.
Using smaller and smaller current probes, we gradually narrowed the
problem down to one cable. The problem turned out to be the following:
There were a lot of mechanical relays on the umbilical tower. All of
them were supposed to have arc suppression diodes on them. On one relay,
someone had installed the diode using leads that were SIX FEET LONG.
Needless to say, by the time the impulse hit that diode, it had already been
radiated and conducted all over the place. The computer interpreted that
glitch as a command to short out the fuel cells.
The diode was installed correctly, the problem disappeared, and
apollo 11 was launched on time. the public never found out about it.
I would love to take credit for this, but it was all my boss's
doing. His name was Carl L. Lennon, and I hope he's around somewhere to read
this. It was 100% due to him that apollo 11 went off on time.
I was just a young dude who would do whatever I was told, instantly,
without stopping to ask questions or even to think. Sort of a high tech
spear-carrier.
Other than a tremendous amount of overtime, I dont think we spent
more than $10,000 to solve this problem.
I still have a couple of those makeshift current probes.
Regards,
Louis T. Gnecco M.S.E.E.,President
TEMPEST INC. 112 ELDEN ST. HERNDON, VA 20170
(703) "TEMPEST" (836-7378)
l...@tempest-inc.com
---------
This message is coming from the emc-pstc discussion list.
To cancel your subscription, send mail to majord...@ieee.org
with the single line: "unsubscribe emc-pstc" (without the
quotes). For help, send mail to ed.pr...@cubic.com,
j...@gwmail.monarch.com, ri...@sdd.hp.com, or
roger.volgst...@compaq.com (the list administrators).
