What a Blast
Bunker Busting Technology
Someone from a UK Ordnance division enquired whether we could measure a hole within a block of reinforced concrete, some 5 metres deep. Initially, this sounded like a fairly straightforward request. Little did I know that this relatively simple request was anything but straightforward! Nothing about this contract was standard. For a start, the concrete block was in a military testing area in the north of the England. The block was five metres wide, five metres deep and high too. It featured a hole that went straight through it which was around 50-60 mm in diameter. I was cheerfully informed that this was the result of a world first – the successful use of a bunker buster missile which had been fired horizontally. I understood that this was the first stage of an ongoing process and whatever – or whoever – created this hole, considered it to be the pilot hole for something even more deadly. This all sounds rather top secret, right, so why am I telling you? Well, first of all, it must have been some 19 years ago, and secondly I wasn’t asked to sign an official secrets act or any sort of confidentiality agreement.
The Requirement
In order to undertake this work, the client created a telescopic arm mounted on a stand that would extend some five metres into the concrete block. My task was to measure the cavity within the block and determine if there were any noteworthy features in the geometry of the cavity. The measurement tool was mounted on the end of the telescopic arm and positioned at the entry of the cavity, then lined up in order in preparation to measure successive cross sections of the cavity. The tool was propelled forward using a crank arm to perform the task of capturing successive internal cross-sections of the hole, thus enabling the creation of a CAD model of the space created by the blast.
Background
So, how did I end up looking into a blast hole within a concrete block on a cold day in the north of England? Well, this was due to the development of a non-contact measurement device that I’d developed. The tool was a unique innovation that had pushed the boundaries of design and electronics to a new level. As an innovator back in the nineties, it was not possible to find computer processors powerful enough to do what you wanted, unlike today. A highly talented engineer who I employed for this project decided that not only would he take on teaching Artificial Intelligence to University Students, but he would also design and build a 100 mm diameter device capable of measuring pipes for Thames Water. To make this work, he went on to design and manufacture an entire Digital Signal Processing electronics system complete with Ethernet network capability, video processing and electronics to drive motors and read optical encoders. Trust me, it took a lot longer to develop those things than it did do list them! The fact that we actually had this entire system assembled and working within one year was nothing short of a minor miracle. Did I mention the system had also to be waterproof and hopefully explosion proof? After the system had been used for a year by Thames Water by their survey division, I then retrieved it and was able to use it for other purposes. It was not a perfect tool - the funding ran out for that project and although it worked, we simply didn’t have the time to refine it. The waterproof Pyrex cylinder at the end of the pipe (in all of the excitement I forgot to mention this was also patented) was not perfectly made and the small imperfections meant that the laser and light stripe sensor were not always in perfect alignment. Also, a scheme that was developed in order to get the system to vary the exposure time of the camera to account for differing light levels had a flaw and never really worked 100%. Nevertheless, the tool would successfully collect cross section measurements – around 1,000 per rotation in a few seconds.
Summary
I don’t remember how we got the work, but it could have been as a result of appearing on the TV show, Tomorrow’s World. For those that are too young to have heard of this show, it was a programme that featured new technologies in a prime time slot on the BCC, back in the day. So in the cold North of England, we started the measurement process and collected successive profiles until we were about one metre into the cavity whereupon it became too small to go any further. I packed up, came back and wrote my report, and official secrets act or not, have never publicised this work until now.
So, why were we selected for the task? I assume that the engineer simply wanted the job done but knew he couldn’t go through the usual channels, so he got friends and associates to knock-up the various elements and brought them together on-site. I’ve always wondered how the hole was made and hoped that it did not involve anything radioactive.
Key Takeaways
- Versatility is key – Your knowledge and skill set can be useful in a wider variety of applications
- Get up and go – the client needed to get a job done and found a way to do it
- Be trustworthy – there is nothing new about bunker buster missiles now, but back then, this was a world first and with our without the official secrets act I did not publicise what I did until now