THE ARTICLE ON BAT guano in the Spring 2004 issue (“High Wire,” by Rockey Spicer) reminded me of an important aerospace use for the stuff. Back in pre- and post- Sputnik days I worked for the Raymond Engineering Laboratories, in Middletown, Connecticut. Because of our skill with explosive actuators, we received a contract to design and build explosively erected antennas for the Mercury, and later Gemini, spacecraft. A set of telescoping aluminum tubes, with flared ends, were stored in a small cylindrical cavity about a foot deep in the top of the spacecraft. At the end of the flight, when the spacecraft was bobbing in the ocean, an astronaut would trigger an explosive charge in the base of the telescope and thereby erect a six-foot rigid antenna to use to contact the ships waiting to recover him.
Creating the right amount of explosive force proved to be a real challenge. Too little charge, and the sections of the telescope would fail to lock together when erected; too much charge, and the telescope would blow apart. One day after many weeks of unsuccessful experiments, our explosives man, Paul Eldridge, brought to work a little rocket-powered racecar he had bought at a toy store. He used the toy’s “rocket powder” in his next experiment, and it worked perfectly. Contacts with the company that built the toy car established that the explosive powder was bat guano. We were able to buy more of the stuff from its South American provider, and we used it successfully in all the Mercury and Gemini antennas. I believe that NASA, recognizing its importance and the difficulty of identifying an acceptable substitute, even prepared a federal specification for it.
John H. Bickford
OQUOSSOC, MAINE
