infra-red measurements on shots Butternut and Koa as instrument checks
and to obtain correlation data. A P2V also participated on events Butternut
and Koa for instrumentation checks and to obtain data for correlation of data

from a surface detonation with those from shots Teak and Orange.

On But-

ternut the monochromator failed to function properly, but the mapper func-

tioned satisfactorily.

On Koa both instruments operated well.

No data were

received from the canister instruments on the drag line.
Tentative conclusions which can be made at this time are:
1.
The Yucca shot appeared timewise as a detonation of one-tenth its
actual yield.
2.
The time to normal second maximum scales directly as the relative density to the one-third power.
3.
The apparent yield scales directly as the relative density to the
two-thirds power.
4.
The radius of the fireball at time to second maximum scales inversely as the relative density to the one-sixth power.
5. No definite indication was received of a change in partition of energy since the apparent change was not sufficient to be conclusive. If there
is a change, it would appear to scale inversely as the relative density to the
0.031 power.
The experiments on effects of atomic weapons on materials and evaluation of a skin simulant were carried out on shots Yellowwood and Walnut.
Approximately 30 skin simulant specimens in various configurations, including
bare and blackened unclothed samples, samples clothed with contact and
spaced fabrics, and samples with various apertures were exposed. Timetemperature histories of the specimens were recorded. In addition, recording
calorimeters and radiometers were used to measure the thermal radiation
incident at the station.
Ablation and neutron vulnerability studies were carried out on shot
Cactus. For the experiments on ablation of material,two specimens designed
to determine the rate and depth of melting of a spherical surface were exposed on a 100-ft tower so as to be within the fireball. These specimens
contained instruments for measuring and recording the time history of the
temperature of unprotected metal at various depths, specimen acceleration,
late fireball overpressure, and shock arrival time. Two additional specimens
spaced 10 ft apart and rigidly connected were placed on the ground at a distance of 250 ft to measure the speed of sound inside the fireball. These
specimens contained transducers and recorders for measuring the time of
arrival of weak shocks from a series of small explosions set off at successive times after zero time.

From these measurements it was hoped to cal-

culate a time history of the gas temperature of the fireball.

As yet, no results are available from these studies. In the case of
the neutron bombardment experiment, the radiation level in the area precluded
immediate recovery. When the level of activity diminished, a search of the
area was made, but the instrument carrier could not be located.

Program 9, General Support

The mission of Program 9 was to provide documentary and technical

photographic support to participating DOD agencies. The documentary support consisted of both still and motion picture coverage of project activities
35

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