FIRST STEPS TOWARD SPACE - Smithsonian Institution Libraries

34 SMITHSONIAN ANNALS OF FLIGHT
propellant, unless available at BPD. Shortly thereafter,
my father was called to a Chair of Aeronautics
at the newly constituted School of Aeronautical
Engineering of the University of Rome.
What Propellant and How Utilized?
The choice of the propellant represented a very
important initial step. Of course, an impressive
amount of very scientific data was already known to
the artillery people; it was, however, limited to
ranges of pressure suitable for guns but not for
rockets. Very little, if anything, was known, indeed,
about the behavior of conventional gun
propellants at pressures below 100 atmospheres.
It might have been for this reason, or out of a
lack of sufficient background, that so many rocket
pioneers derived their concepts from the very
empirical formulas of pyrotechnicians rather than
from the science of artillery. A notable exception
to the rule was provided by an Italian pioneer who
proposed the use of dynamite for rockets. Maybe he
FIGURE 1.—First solid propellant test chamber.
was the precursor of project Orion! I would like to
add here that, in reality, the intuition of the rocket
pioneers may not have been so bad because it is
clear today that the greatest present and future
achievements of solid propellant boosters follow a
line which, conceptually, is more directly derived
from pyrotechnics than from gunnery. As a scientist,
however, my father was definitely more attracted
by the clear background of artillery powders
than by the obscure concoctions of fireworks, and
his natural choice went immediately to the doublebase
powders.
The next step was to decide how to utilize these
powders so as to obtain the relatively long deflagration
times required by rockets, as compared to the
extremely short times characteristic of guns. It was
immediately clear that the key was to use the largest
possible "grain" size, particularly of the "constant
burning-area" type. However, the great advantages
that might derive from the possibility of "restrictedburning"
grains did not escape my father's searching
mind, and he decided to work in both directions.