Spycraft - Melton [109]
Mallory first built its reputation during World War II with a mercury cell developed by the company’s cofounder, Samuel Ruben. Not only did the mercury cell pack more energy capacity into the volume of the battery case than other chemistries used during the war, it also operated well even when deployed in tropical temperatures. After the war, the mercury battery design fell into obscurity. It was still manufactured, but just barely, and only as a highly specialized item for a limited number of industrial devices. “The RM-1 was in the marketplace for use in medical applications and as a reference cell for testing other equipment because of its consistent, precise voltage,” explained Tom Linn, who headed the Agency’s battery program, “but they were not widely used at all.”
Still, it was considered the most viable cell available and TSD “forced” its use for extended applications. Although available in the right voltage and size for TSD’s needs, the battery was not designed for use extending over months or years. It exhibited a tendency to fail prematurely, and like virtually all commercial batteries at the time, the RM-1 hated audio operations. The constant slow and steady power drain of 1.5 volts required by the SRT-3 fostered internal crystalline growth that could eventually short out the cell.
TSD studied the failure mechanisms of the RM-1 cell and through a process of identifying failure modes, correcting each one, retesting, and further correction, the RM-1 evolved into a deployable component. Eventually a series called the “Certified Line” was produced. “That was our certification,” noted Linn. “It was certified for sure, certified for CIA’s clandestine audio operations.”
Later, when the heart pacemaker industry emerged during the 1970s, the manufacturer applied the knowledge learned in building the TSD battery. “I think it’s fair to say the first pacemaker battery—a mercury battery—was a TSD special design cell,” said Linn.
The requirements for power cells used in pacemakers and audio bugs were remarkably similar. Power must be sustained, reliable, and produced at a predictable, consistent level. Extended lifetime and small size are required since cells are not easily accessible after they are implanted, so replacing a cell is done as infrequently as possible.
The early SRT-3 battery-powered installations were configured with multiple standard D-cells linked in parallel. Eventually this would change when OTS began building cells in custom-made “cans” or containers. Not all of the specialty cans were metal containers; some of the housing materials could be molded to fit unusual concealment shapes or conform to human movement. Thin, flat, flexible, elongated, and curved shapes of metallic and nonmetallic containers for various power cell chemistries were developed and tested, all for increasing the options for concealment to enhance their operational use.8
TSD chemists also explored the possibility of using alternate substances to build what, in effect, would be a super-battery. “We did the calculations to try to find, of all the known chemical materials, what were the most energy-dense,” said OTS scientist Stan Parker, who spent a lifetime working on battery chemistries. “We got some remarkable results from the calculations. But when we looked at the toxicity of some of those materials, we said, ‘My god, I wouldn’t want to be in the room if they were going to actually try to use these. I wouldn’t want to even be in the same county.’”
It became clear that the volume of a battery could be shrunk only so much. A variety of exotic elements that yielded longer life in a more compact size were tested, but, inevitably, the