FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

NUMBER 10 45
and myself, the aim of the research had switched
toward the study of monopropellants. Also, the research
was now financially supported by a new
sponsor, the Italian Air Force. It had new headquarters,
the laboratories of the Istituto di Aeronautica
Generale of the School of Aeronautical
Engineering of the University of Rome. We also
welcomed to our program a new, very competent,
collaborator, the Doctor of Chemistry Riccardo M.
Corelli, later Professor of Aeronautical Technology
at the same school.
I remember quite distinctly how the first idea of
the monopropellant was born during an evening
stroll under the trees of Via Nomentana. My father
was wondering about the possibilities of controlling
solid propellant burning by introducing it in the
combustion chamber as a slurry of fine solid-propellant
particles in suspension (but not solution) in a
liquid. The discussion centered on the way combustion
of such a mixture could take place. I remember
how, in what was a sudden illumination for my
still unexperienced mind, I realized the meaning
of thermochemical calculations which, independently
of the burning mechanism, allow a simple
prediction of the composition and state of the gases
resulting from the combustion of any mixture of
chemicals as soon as the temperature is sufficiently
high.
In practice, abandoning the not very practical
FIGURE 18.—Monopropellant gasification apparatus.
idea of a solid propellant slurry, we chose to work
with a liquid explosive, desensitized by dilution
with an inert solvent. The most easily available and
one of the most effective liquid explosives being
trinitroglycerine, we decided to try it despite its
bad reputation. However, we also considered other
substances, such as dinitroglycerin or dinitroglycol.
We performed a limited number of tests with these
substances. It was known that a relatively small fraction
(30 percent) of an organic solvent such as
methanol could practically make trinitroglycerin
insensitive to shock. Dr. Corelli carefully checked
this and other statements in the literature on the
subject, with a small amount of the explosive prepared
in our laboratory. After this I felt sufficiently
confident to carry personally on a night train from
Turin to Rome a few liters of the mixture which
had been prepared for us at the powder plants of
Avigliana. This was, of course, a flagrant violation
to the official regulations concerning the transportation
of explosive materials, and I shudder today
at the responsibility I was taking. However, it was
the only way to avoid the endless red-tape involved
in legal shipment.
Gasification tests were conducted in the apparatus
shown in Figure 18. The monopropellant m
contained in the tank b was pressurized, through
the separating piston p by the gas of bottle a. The