Beam Rider

by Stuart Bowen, September 29, 2010

I should have been an experimental physicist or per­haps even an astrophysicist. One disadvantage to the latter profession is that you can't really get close to the explo­sions you're studying. “A good explosion,” a friend once said, “is one you can feel right here,” and he pounded his wishbone with his fist. Of course I'm not sure I would really want to feel a supernova —

There were barriers to my pursuit of a career in high energy physics. One was terrible study habits. I never did learn how to study. I was always going off on tangents of my own. Sometimes I profited from such digressions, but my grade point average surely did not. Also, my IQ is something less than 198, the number modestly pro­claimed by “Humble Ken,” my first roommate in col­lege. Still, I did the best I could and spent most of my life in the explosives business one way or another.

From my very earliest years I have had a fascination with sheer, pure, raw energy — and not always as mani­fested by explosions. One of my few memories from age 4 or 5 in St. Louis is the apocalyptic electrical storms we had in the summer months. I would point out the gath­ering purple clouds to my young playmates. Lightning would dance from cloud to cloud and from cloud to ground and seconds later peals of thunder would roll across the neigh­borhood. “I think a tornado was forming over there, don't you?” I would ask the boy next to me. “Doesn't that look like a funnel cloud dropping down?” Pretty soon, all my playmates were in tears and running for home.

Ergs, joules, watts, kilowatts, kilotons! Energy cre­ated by man or unleashed by the gods. Energy for better or worse. I wasn't so concerned with the application (or mis­application) of energy as I was with its creation. Energy for its own sake, you might say. Yes, I liked to see things come apart — come apart rapidly and vio­lently sometimes. But the “things” never included peo­ple. I shunned that horrible and macabre branch of mili­tary science called “terminal ballistics.” I don't even care to elaborate on that term here. I will leave it to the reader's imagination. (Think: blocks of gelatin.)

Born at the end of the steam era in this country, I loved to stand as close to the railroad tracks as my par­ents would allow, the better to absorb roar of all that heavy, moving machinery, feel the vibration of the ground and allow the rushing air (and sometimes the steam) to wash over me. Much more recently, I stood within a dozen or so feet of the tracks in Suisun City as the Union Pacific Challenger, “the world's largest oper­ating steam locomotive,” roared down the Capitol corri­dor at 60mph. It was almost a relig­ious experience. From my earliest years when asked what I wanted to be when I grew up I said, Engineer, by which, of course, I meant locomotive engineer. Alas, as we all know, steam was supplanted by diesel power. And I settled for the some­times title of aerospace engineer.

I did quite well in high school chemistry, even serv­ing as assistant to the teacher. In fact, I did so well that it ulti­mately led to a trip downtown in a squad car. But that's another story for another time. Our friend and next-door neighbor was a graduate of Cal Tech and it was a given that I was going to go there also. But that was not to be. (See second paragraph above.) Nonetheless, our neighbor intro­duced us to the Friday evening public lec­tures and science demonstrations at Cal Tech. My favor­ites were those that had to do with cryogenics (very low temperature research — liquid air and such) and the high-voltage lab. Also, the Southern California Coopera­tive Wind Tunnel which was operated in part by Cal Tech. (I love the fact that they could only bring it up to full operating speed at 3am when power demand in Southern California was at its lowest. I love the idea of the needles on those megawatt meters slowly swinging from left to right as the machinery came up to speed.)

But back to cryogenics. I was intrigued not only by large numbers in the energy field, but also by extreme tem­peratures — extremely high or extremely low. I was fasci­nated by the concept of absolute zero when every­thing is supposed to stop. The public lecture at Cal Tech never got down to absolute zero, but they did get down to 320°F below zero. That's pretty extreme. The lecturer would dip a fresh rose into the liquid nitrogen for a few seconds and then drop it on the floor. Of course, it would disintegrate into a thousand pieces. Or he would immerse a hot dog for a longer period of time and then hit it with a mallet. Again, pieces flew everywhere. Right after that, he would pull on a rubber glove saying, “Now, what you don't want to do, is dip your finger into liquid air,” and he would appear to do just that. He would pull his “fin­ger” out of the flask and, before anyone could scream, hit it with the mallet. Of course it shattered and the audience gasped. Again, hotdog! “Now this, you definitely don't want to try at home,” the professor warned as he picked up a foam coffee cup half full of liquid nitrogen and appeared to drink it. Almost immediately he blew out a most satisfying four foot plume of white vapor. I knew instantly that I would have to try it at home. For those of you who are also tempted, there are several secrets to this parlor tricks. First and foremost, don't actually drink any liquid nitrogen! (That seems fairly obvi­ous, doesn't it?) Use a foam cup so the insulation protects your fin­gers. Try to pour the liquid nitrogen over (not on) your teeth and fillings. And finally, expel it fairly promptly. As with a drop of water on a hot skillet, the heat of your tongue and mouth will protect you for a second or so. Oh yes, there is one more caveat: don't allow the liquid nitro­gen to spill down your shirt front as you raise the cup to your lips (as happened the last time I demon­strated this trick for my son and his friends).

The high point of the Cal Tech lectures was when they opened up the high-voltage lab and invited the pub­lic inside. (I wanted to try some of that at home to. I bought a very high voltage DC power supply, originally used in a ground approach radar system, and crates of high voltage capacitors. Fortunately, I never got around to hooking this stuff up — I believe what I was aiming for is called a Marx generator — which perhaps was a good thing.)

The high-voltage lab no longer exists, but it was a large concrete building, perhaps three stories high, open from floor to ceiling. Along one wall ran the visitor’s gallery, a mesh steel catwalk with an iron guard rail. “There was electricity in the air,” is a popular expres­sion. In the lab, it was literally true. As they were giving us demonstrations of corona discharge and simulated lightning bolts, you could extend your arm toward the high voltage sources and then draw a small spark from your elbow to the iron guard rail. When I proudly showed this trick to my dad, he frowned and said, “I don't know that I would do that.” The target of the light­ning bolt which may have been ten feet or more in length was an old Ford coupe in the middle of the floor, the technician wearing earmuffs sitting behind the wheel. The tension was palpable, as the saying goes, as the audience listened to the nasty hum of voltage building to the discharge point. When the man-made lightning bolt struck the top of the car you could see secondary dis­charges over the tires to the ground (if you didn't blink too long). Supposedly, the human subject was safe, sit­ting inside what was a “Faraday cage.” But I don't know that I would have volunteered for that duty.

Those demonstrations at Cal Tech, exciting as they were, paled into insignificance compared to those at the Naval Ordnance Test Station at China Lake for Armed Forces Day. It took a couple of years, but I finally talked my parents into driving up to Ridge Crest and China Lake in May of my last year of high school. It proved to be worth the long drive, at least in my eyes. This would have been 1957 and, while safety has always been a top priority at the facility, they were perhaps a little more casual about things back then. For example, for weapons demonstrations, they used live ordinance instead of the Hollywood style special effects adopted for their 50th anniversary celebration. (I also got a taste of how seri­ously the Navy takes safety when a driver and I showed up a few years later at the wrong gate with a truckload of Shrike warheads which we were returning from envi­ronmental testing. The gate we were at opened into a residential area. We were roundly chewed out as I guess we deserved.)

NOTS/CL, as it was known then, is a huge, land­locked Naval test facility occupying a large chunk of California west of Death Valley and south of the Owens Valley. Founded jointly by Cal Tech (again!) and the US Navy during World War II, it had only been in existence a little over a dozen years at the time of our visit. (And this was six years before President Kennedy's visit.) I even thought I might want to work there someday. Our visit began with a self conducted tour of Michelson laboratory, named for the Nobel prize winner, Albert Michelson who did some of the earliest work in meas­uring the speed of light. The lab emphasize applied research in photo optics, especially infrared and electro­magnetic radiation in general. The famous Sidewinder air to air missile, still in service, had its birth there in the early 1950s.

From Michelson, as I recall, we drove several miles northwest across the sprawling base to the SNORT rocket sled test track. I remember this acronym but I'm not sure what it stood for. How about Subsonic Naval Ordnance Research Track? The demonstration was scheduled for 11am and we  chatted with the personnel while waiting for the event. Observing that the vehicle (sled) seemed pretty heavy — and guessing that it went pretty fast — I asked one of the technicians how they stopped it at the other end of the track. “There is a long water trough and a sturdy scoop on the sled that dips down into the water,” I was told. “It's pretty effective — if we remember to fill the water trough. One time we forgot and the sled just kept on going for several miles out across the desert.” I had a mental image of one tech­nician turning to another in the control center, asking if he had filled the trough. And the other guy saying, No — I thought you did.

The appointed time approached and we were all standing outdoors, off to one side of the track, presuma­bly to avoid the backblast. I remember thinking to myself that I hoped the solid rocket motor being used was of a proven design because we seemed to be standing awfully damned close. We got the traditional countdown over the PA system and at “zero” all hell broke loose! There seemed to be two explosions, a second or so apart. The second you could definitely feel in your chest. It turned out that everything had worked as planned, the audience just didn't know the whole plan. The rocket motor ignited and the sled disappeared in the blink of an eye. The second explosion, I was informed later, was “about two pounds of TNT, off to the side of the track.” The technician told me they had just wanted to demonstrate the switch contacts on the track that would normally be used to trigger a high-speed camera or other instrumen­tation. It was an effective demonstration. I wondered how many members of the audience had headed to the restroom and subsequently to a local laundry service in Ridge Crest.

But all this was only a preamble to the main events of the day. After viewing various static displays of aircraft and support equipment, we all lined up along the central portion of the two-mile long main runway. Giant loud­speakers on poles kept us informed of what to expect. Cameras and binoculars were much in evidence. First, we were told, there would be a “scrap propellant burn.” At a distance of a mile or so across the runway, several tons of solid propellant were to be ignited for disposal purposes (and to impress small children and adults alike). It was indeed quite a sound and light show. It started quietly enough, but built in intensity rapidly. A few large rocket propellant grains was whistled across the sky of their own volition. The smoke was prodigious and people were actually turning away from the intense radiant heat. As the huge cloud of smoke rolled out over the sagebrush (was this supposed to be “smokeless pow­der”?), a large, twin rotor helicopter appeared on the scene and rescue personnel in fire retardant suits rap­pelled down to rescue imaginary burn victims. For someone of my age and inclinations, it was a highly sat­isfactory exhibition.

There were flyovers of various aircraft doing differ­ent maneuvers. There was at least one supersonic low altitude flyby. These were particularly impressive because you had no warning at all. (This was before supersonic flights were ruled out nationwide. The only sonic booms I have heard in the past 20 or 30 years were those of the space shuttle coming in to Edwards Air Force Base.) There were low level strafing runs with Vulcan 20mm “Gatling gun” cannons. The guns sounded like tearing silk and they killed a lot of mesquite and creosote bushes. We were even treated to a live fire demonstration of the then brand-new Sidewinder air-to-air missile. At that time, it had only been operational for about a year. China Lake personnel were rightly proud of this economical and highly effective weapon. (According to Wikipedia it has 210 documented kills to date.) I'm guessing the missile was launched from an F-4 Phantom (or perhaps even something earlier than that) against a radio controlled drone. Although it was almost a point-blank shot by aerial warfare standards, everything worked as advertised. Our tax dollars, as represented by the drone piling into the desert in a large ball of fire, were well spent in my view. I wondered if they had put extra fuel on board.

At last we were ready for the grand finale. A two-stage Terrier surface to air missile was to be launched against another drone. The announcer kept up a steady patter of chitchat, building expectations. With binocu­lars, we could just make out the ground launcher a mile or more away. (The Terrier was intended for shipboard use as “mid-level” protection between the antiaircraft guns and the escort fighters high overhead.) It was known familiarly as a “beam rider,” since it would fol­low the ground-based radar beam to the target. We scanned the skies for the approaching drone. The announcer told us — again — that this would really be something to see, something to tell our grandchildren about. “These missiles cost $350,000 each,” (or whatever the price was in 1957 dollars) “and we are demonstrating one here today for you, the taxpaying public.” The drone finally came into sight at a respectable altitude (8000 feet? 12,000 feet?). The Terrier launched and the roar of the first stage reached our ears a few seconds later at about the same time as the first stage separated. For another second or so, the upper stage continued on toward the target. Then it corkscrewed violently and blew up, well short of the target drone. This was fol­lowed by silence, both from the range, from the audi­ence, and, notably, from the loudspeakers. The only sound we heard above the whisper of the desert breeze was the insolent drone of the drone, which was continu­ing on to the south, unscathed. Finally, our heretofore cheerful master of ceremonies spoke into his micro­phone. “Well, uh, folks, uh, it seems there has been some kind of a malfunction. It's, uh,  not supposed to do that. I will, uh, see if I can find out what happened and, uh,  get back to you.” He never did.

A year later I found out in a most unlikely fashion what had indeed happened. I don't know how the subject came up, but I found out that my drafting instructor at Pomona College was in the reserves and had been pre­sent at NOTS/CL on that Armed Forces Day open house. Even more unlikely, he had actually been part of the launch crew for that very missile. “What happened?” I asked. “The radar was powered by a diesel generator,” he explained. “We ran out of diesel fuel and everything shut down. When the Terrier lost its radar beam, it self-destructed, just like it was designed to do.” Then he added with a wry smile, “Your tax dollars at work.” Again I imagine the conversation none of the audience heard: “I thought you checked the level in the fuel tank.”

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