Cloud Tracking
Tracking the debris with aircraft was the primary method planned to
Three t pes
verify radioactive cloud travel in the predicted direction.
of survey were used to determine the cloud location:
(1)
of WB-29s scheduled specifically for tracking purposes,
"Wilson" f ights
(2)
inflight data
from all aircraft flying between Bikini and Enewetak for the first 2
hours after detonation, and (3)
radio intercept of reports from and
tween cloud-sampler aircraft.
The major areas of concern were
(in order of importance):
1.
Downwind,* especially Enewetak and Ujelang
2.
Upwind
3.
Upwind of the native-populated atolls to the southeast
4.
Air and surface transportation routes through Wake
and the Marshall Islands.
Figures 21 and 22 show the planned flight paths of the Wilson cl
tracking aircraft.
Clouds more than 24 hours old were considered su
ciently dissipated to be harmless.
The 24-hour time period translat
into a distance of approximately 500 nmi
(926 km).
Cloud Sampling
Cloud~sampling operations were undertaken to obtain scientifical
valuable data for the evaluation of nuclear explosions.
These data
re
collected as gaseous fractions and samples of particulate material f
the nuclear clouds.
Operation IVY was a significant milestone in th
of manned aircraft for cloud~-sampling operations.
use
LASL scientists p
ced
a heavy support requirement on the Air Force to sample the cloud pro
ced
by the world's first thermonuclear device, IVY-MIKE, and this requir
ent
was carried over into the CASTLE series.
Planning between the LASL and the Air Force Special Weapons Cente
(AFSWC) was undertaken in 1951.
Several different types of aircraft,
cluding the B-36, B-47, 8-45, F-89, and F-84 models were considered f
* Refers to the low-altitude trade winds, rather than winds aloft.
132
in-