What follows is unclassified. At least as far as I know. It comes from my fading memory and the so-called "open literature." The connections, if any, are pure speculation on my part. This train of thought was triggered by the recent film, "Argo" (2012), about one aspect of the Iranian Hostage Crisis at the end of the Carter administration.
My flirtation (if I can even use that word) with this historical event came in the winter of 1979/1980. At that time, I was running the Test Department for a small Bay Area aerospace company specializing in engineering and producing precision explosive components for military aircraft and missiles, e.g., crew ejection systems and missile stage separation systems. Our customers were mostly the prime aerospace contractors and Uncle Sam himself. This particular inquiry came from McDonnell Douglas, St. Louis. Although I never saw the words on any piece of paper, it was clear from the outset that this project had the highest priority. It was urgent in the extreme. No limit on overtime; no expense spared. It ran almost 24/7 right through Christmas. By my recollection, it took something like six weeks from start to finish--something of a record in the aerospace business.
The assignment was this: We were to design, build and test a destruct system that, on remote command, would destroy the electronics bay of a long-range cruise missile--destroy it beyond any possibility of reassembly. As I recall, we were to build four "shipsets," test one and ship three to St. Louis by special military aircraft out of Travis Air Force Base (our neighbor). Questions in my mind at the time: Why didn't such a thing already exist and why did somebody need it so urgently RIGHT NOW?? The speculation started.
I only remember two acronyms for sure on this special project. (The aerospace biz was big on acronyms, probably still is. We could hold almost complete conversations just using acronyms. Example: "We need a ROM RFQ for the Delta IV RETA/FETA ATP to support the RTP/PO ASAP." You probably get the last one. Don't ask me to translate the rest.
The acronyms I remember for sure are BGM-109D and DSMAC. The first makes more sense to the uninitiated than the latter. GM, as you have already guessed, stood for Guided Missile. I believe the B stood for Basic or perhaps Baseline--a missile whose launch environment could be reconfigured without re-designing the weapon from scratch. That is, with minor changes, it could be launched from land, sea or air. In fact, the BGM-109D was an early version of the Tomahawk cruise missile. In my mind, at least, the name "Tomahawk" implies a ship-launched weapon. Now it's important to note that operational evaluation of the Tomahawk didn't begin until January of 1981, a full year after the program I am describing. It didn't actually enter service until 1983, according to our good friend, Wikipedia. The other important thing to note is that all of this preceded the GPS system by at least ten years.
Which brings us to the second, more esoteric acronym. DSMAC stands for Digital Scene Matching Area Correlation, a mouthful for anyone. In other words, the Tomahawk would compare where it was at any given time with the pre-programmed course based on visual cues recorded previously. (Presumably, this is where we might veer into classified territory.) DSMAC was the greatest advance in guiding guided missiles since inertial navigation based on gyroscopes. And gyroscopes date clear back to Hitler's V-2 program run by Wernher von Braun, the German rocket scientist who came over to our side after the war. Gyroscopes, at least in those early years, were pretty crude mechanisms. Maybe this explains why some pundit with a twisted sense of humor said "von Braun aimed for the stars, but sometimes hit London." Not funny to a Londoner.
But back to DSMAC. It was important to someone that if--IF--one or more of these weapons were to be used prematurely against an un-named enemy, it was critical not to leave the DSMAC module lying, say, in some desert where it could be recovered and studied. Or at least not leave it in one or several pieces. What was called for was "smithereens"--remnants that absolutely, positively could not be reassembled and reverse engineered. That's where we came in. McDonnell-Douglas shipped us an actual DSMAC module and we went to work. (Maybe it was an elaborate mock-up, but I was told it was the real thing and we were going destroy it. What still puzzles me is that it wasn't classified. At least the external view wasn't classified. I don't think our customer had time to build a mock-up, but one may have existed for other purposes.)
After watching "Argo,", I asked myself how it's possible for a nation (Iran) to nurture such vehement and enduring hatred for another country (US) for decades? Perhaps the answer begins in the summer of 1953 when the CIA (and MI-6) engineered a coup against the democratically elected Prime Minister of Iran (Mohammad Mosaddegh) and installed our guy, Reza Shah Pahlavi, who invited the oil companies back into Iran. And, of course, we backed the Shah to the hilt, even selling him the latest and greatest made-in-America weaponry in the form of F-14 "Tomcat" fighters. (Digression: I seriously considered going to work for the Shah--in the guise of Grumman Aircraft Corp.--in the early 70s to help maintain the emergency crew egress systems on his shiny new toys sitting on the runway in Isfahan. I had visions of starting a world class collection of Persian rugs. Hah! In retrospect, that would not have been a good career move!)
The animosity between the two nations continues to this day. Although it was years after the period discussed here, relations were probably not helped by the downing of an Iranian airliner in July of 1988 by a surface-to-air missile from the USS Vincennes.
Two hundred and ninety died including sixty six children. "Oops!" said the captain of the Vincennes, which was in Iranian waters at the time, "We thought it was an F-14." This tragedy got very little coverage in the Western press and, only rarely, has it been connected with the downing of Pan Am Flight 103 five and a half months later (270 fatalities). This writer is anything but an apologist for the Iranians, but this double tragedy casts light on the mindsets on both sides.
Early in the Iranian hostage crisis, President Carter made the decision to launch a secret military rescue mission called "Eagle Claw." After several months of hasty preparations, in which my company probably played a part, the rescue mission was launched on April 24, 1980. As most of us now know, Eagle Claw couldn't have gone much worse. Eight RH-53D helicopters (Sea Stallions, modified for mine sweeping) took off from the aircraft carrier USS Nimitz to rendezvous with several C-130 transport and tanker planes at "Desert One," a remote, top secret site inside Iranian territory. Due to sand storms, radio silence and other complicating factors, only six helicopters made it to Desert One and one of those had lost its primary hydraulic system. The crew was willing to continue the mission, relying on the back-up hydraulic system, but the squadron commander was not. He decided to ground the crippled helicopter. Shortly thereafter, the overall commander decided to abort the whole mission. But even after that, things continued to go downhill. During refueling, a helicopter ran into a C-130 tanker. Eight US military people died in the crash. (Thank you, Wikipedia, for much of this background.)
Shortly after Christmas of 1979, we completed our mysterious assignment. No one mentioned environmental testing, my specialty. There wasn't time for vibration or humidity testing. But then this hardware wasn't going into long term storage in a hot, humid explosives magazine nor was it going to accrue hundreds of hours of flight vibration hanging under the wing pylon of a B-52. It was going to be used ASAP.
Our customer had given us a fairly generous do-not-exceed weight allowance and we used most of it: high-core-load (RDX explosive), copper-sheathed linear shaped charge. Smithereens were achieved. Afterwards, the smithereens were gathered up, bagged, and shipped back to the customer. If the DSMAC module we blew to kingdom come WAS the real thing, it was a damned expensive piece of electronic gear we destroyed. The three remaining destruct system shipsets went to Travis AFB on our licensed truck and from there flew to parts unknown.
And here is my speculation. (I'm hoping I don't get a midnight knock on my back door.) One shipset may have been held in reserve. Two, or possibly three, were installed on BGM-109 Tomahawk missiles--very early versions which had not yet been fully tested and proven. Presumably, they were aimed at carefully chosen targets in Tehran to create a diversion and general confusion which, in that age before cruise missiles became operational, they surely would have accomplished. But they were never launched and most of us will never know the whole story.
Some weeks after the final test, we received a commendation from the Defense Department for "vital services rendered to a grateful nation." Or some such wording, according to the president of the company. But I never saw it. This award didn't officially exist. It may have hung in the room that also didn't exist. I never saw that either, but supposedly it was an ultra-secure, heavily-shielded room with no communications going in or out. Presumably it was a repository for classified information. If you asked about it, the response was usually "What room?" And so: “Award? What award?"