The Partnership: A History of the Apollo-Soyuz Test Project|
[xv] Controversy often
surrounds the conversion of the Cyrillic characters used in the
Russian language into the Roman letters used in English. In the
absence of a universally accepted standard, we have transliterated
Russian personal and place names after the pattern established by the
Soviets themselves and as recorded in the English language version of
the ASTP documents.
The metric system poses an equally thorny
problem. NASA is committed to the national goal of metrication, and
in 1973 the space agency prohibited the use of English weights and
measures in all publications, including its historical series. But
NASA engineers were not thinking metric all the time. ASTP documents
often recorded specifications in metric form, but they almost always
added the English equivalent. Furthermore, the actual production of
the American components for the joint mission was done on
manufacturing tooling calibrated in standard American engineering
units. As some passages in the text indicate, this English metric
schizophrenia caused occasional troublesome moments when the switch
from metric drawings to English tooling required extra care to
determine that all the critical dimensions were correct. In this
history we have followed the trend to metrication, and we have used
the systeme internationale
d'unites (SI) with one major
exception. We have chosen millimeters of mercury to designate cabin
pressures. The Soviet space community has commonly used this
measurement, while their American counterparts have used pounds per
square inch (psi). Neither side talked in pascals (newtons per square
meter), the approved SI measurement, which would have puzzled nearly
everyone who worked on ASTP.
Another metric unit requires explanation. In
the English system, "pound" is used to describe both mass and force.
The creators of the metric system devised two distinct units, the
familiar gram for mass and the less familiar newton for force - thus
pounds of weight become grams, but pounds of thrust become newtons.
Where we wrote about thrust, we used both newtons and the equivalent
in pounds. Elsewhere, we have given only the metric units to keep
from cluttering the pages with endless conversions in parentheses.