From: Spike Jones (spike66@ibm.net)
Date: Sat Sep 25 1999 - 00:14:50 MDT
Warning: longwinded Athena story follows.
Robert, the reason I brought up the Athena launch system (successful
today) was that I used to work on that project. In1991 I was
on the proposal team and was offered a chance to work on the
development. The notion appealed to me since I was reading Gould
at the time regarding the concept of preadaptation in evolution
[a structure evolves for one purpose and is used for another, such
as feathers evolved for temperature regulation, eventually being
used for flight]. In a vaguely comparable way, the technology for
Athena was preadapted from the Fleet Ballistic Missile.
Athena was called the Lockh.eed Launch Vehicle (LLV) in those
days. We had a bunch of rocket scientists preadapted to building
submarine launched solid rockets, the industrial infrastructure
for mixing and casting solid rocket fuel, and a vacant launch site
down at Vandenburg which was preadapted for launching
space shuttles but was abandoned, never having been used
for that purpose.
Somebody asked why not use these facilities and build the ultimately
simple commercial launcher by using the Vandenburg site, solid motors
and building the structure with larger margins [heavier] than is customary
for space flight hardware to save on analysis and testing.
It was a low tech low cost approach, and it was ugly. Solid motors,
dirty, low performance low tech, ewwwww gross! I
can imagine my colleague Doug Jones is rolling his eyeballs
by now. {8^D But it was cheap, so off we went. It was
a really fun project! No government money, so the focus was
on cheeeeeap! Cut corners wherever you can. That isnt the
normal way aerospace work is done, but we had a ball with it.
Turns out, the government did get its nose into our business:
in the command destruct system. They didnt care if we wanted
to risk our bird, but they wanted to make DAAAM sure we had
up-to-spec reliability on the command destruct system, so they could
for sure blow the thing up should it veer off course. One little
rocket crashing in downtown LA can spoil your whole day. {8^D
So. I was in charge of testing the command destruct receivers
and electronics. If you get a chance to see a picure of the Athena
close up, look for four sets of three thingies protruding from the
otherwise smooth skin of the payload fairing. These are three
types of command destruct antennas, S band, L band and UHF.
There are four of each, one on each quadrant of the bird, so no
matter what, there are at least three different frequency bands
in view of the command destruct transmitter. If any one of
twelve receivers gets a destruct command, then BOOM. I
certified these.
One of the buy-the-risk ideas used on LLV was in the hydraulic
system. Instead of having the customary closed system, this nozzle
actuation system used pressurized hydraulic fluid, then when the fluid
was on the low pressure side, it was thrown overboard instead
of being circulated and pumped back up to high pressure. This
isnt the customary high performance way, but it is the cheap
approach, since it removes the need for a hydraulic pump.
An unforseen problem occurred upon launch in 1994. The
spent hydraulic fluid is exhausted inside the aft skirt just
forward of the nozzle. Turns out there was an eddy that
formed there, air circulating in a fast tight circle inside
the aft skirt. The hydraulic fluid got caught in that eddy,
vaporized, caught on fire, burned and distroyed the nozzle
actuator system and disappointed a bunch of us
rocket scientists as we watched it on the video. Had we
done it the normal way, we would have used computational
fluid dynamics and foreseen the problem, but this was
a cheap buy-the-risk unmanned program, so none of
that was done. That analysis was one of the corners
that was cut. {8-[
I was one scared cat when we saw that the bird was out of
control [it began wagging plus or minus about 40 degrees,
quite obviously divergent in all axes.] Altho I am a devout
atheist, I began chanting: oh god, please god, oh shit
oh shit oh shit... etc, because I knew we were now
dependent upon the command destruct system, which
I helped certify, to keep from dropping this damn thing in
downtown LA, and spoiling our day. Within a twenty
seconds, I was put outta my misery by a huge explosion.
We sat there stunned for a minute, then I quietly stood
up, took off my LLV hat, dropped it into the waste
basket and walked out.
Now I wish I had that LLV hat. {8^D spike
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