Spike Jones (
Fri, 24 Sep 1999 23:14:50 -0700

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