Chapter
2
BACKGROUND AND THEORY
Cloud phenomena have been studied photographically on most of the test operations in
the past. These studies have been carried out by Edgerton, Germeshausen and Grier,
Inc. (EG&G), under the auspices of the Los Alamos Scientific Laboratory (LASL) on
Operations Greenhouse (References 1, 2); Buster (References 3, 4); Tumbler—Snapper
(References 5, 6); Ivy (Referenceg 7, 8, 9); and Upshot—Knothole (Reference 10). The
Greenhouse measurements were taken for analysis by groups at the USAF Cambridge
Research Center and Rand Corporation, who reported those results in detafl. All of these
programs were carried out with rather limited objectives.
All measurements were taken with ground-based cameras until Ivy, whenthe first
attempt at aerial documentation was made. These data were far from perfect but provided invaluable experience in planning the Castle program. As it turns out, the same
statement can be made concerning the Castle results: The data are incomplete, although
- they are the best yet obtained; the experience shows many ways in which they could have
been improved.
2.1
PLAN FOR CASTLE
At the request of the Armed Forces Special Weapons Project, a technical proposal
(Reference 11) for the Castle cloud-study program was submitted, and was followed by
a detailed technical plan (Reference 12). This plan recommended the use of several
aircraft, at 30,000 to 40,000 feet, together with ground-basedstations. The aircraft
were to be placed 75 to 100 miles from ground zero in different directions but in the
two western quadrants to photograph the silhouette of the cloud against the dawn sky
light. Wide-angle lenses were to be used to keep the entire cloud w’thin the field of
view for upwards of an hour. The cameras were to be mounted on automatically stabilized platforms to control the tilt, and the aiming direction of the camera was to be recorded automatically from a gyro repeater. Accurate navigation logs were needed to
keep track of the aircraft position throughtout the run. As will be seen, these requirements were not entirely met; it is clear now that they are all truly necessary and cannot
be compromisedif all of the objectives of the program are to be satisfied.
;
During a meetingof Program Directors at LASL, in June, 1953, a decision was.
reached to separate the airborne and land-based photographic programs. ‘he landbased portion was reduced in scope, placed inder LASL Project 13.2, and carried out
entirely by EG&G., Inc. The airborne portion was placed under AFS'WP Project 9.1;
the photographie work was assigned to the Lookout Mountain Laboratory, USAF, while
EG&G.., Inc. furnished advice and censultation in planning the program, analyzing the
films, and reporting the results.
2.2
THEORY
Since Project 9.1 was concerned with observing the cloud phenomena and not
with explaining them, the theoretical background {s extremely simple. Tha size
12
SECRET
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