Shot Name	Date	Location	Yield	Weapon Placement
X-Ray	April 15	Enjebi Island	37 KT	200-foot tower
Yoke	May 1	Aomon Island	49 KT	200-foot tower
Zebra	May 15	Runit Island	18 KT	200-foot tower

BACKGROUND.

Operation Sandstone was proposed and approved as a weapon development test series. Its purpose was to advance U.S. nuclear weapon technology to the point where bombs could be efficiently fabricated on an assembly line rather than hand-assembled in the laboratory.

While this series of three tests was clearly structured for nuclear weapon design, it was agreed that nuclear weapon effects experiments could be fielded as long as they did not interfere with device operations or diagnostics. Within these constraints, the DoD designed tests to:

1. Study radioactive debris and fallout
2. Observe blast response of various concrete and steel structures
3. Assess radiation shielding provided by various structures
4. Measure nuclear blast loads on, and the response of, operating aircraft
5. Assess nuclear detonation detection concepts.

The Sandstone tests occurred very early in the evolution of nuclear weapon effects testing, and the experiments and measurement techniques were relatively unsophisticated. Even so, potentially useful effects data were recorded. The motion picture records of the bursts in particular contain valuable data relevant to shock wave and fireball analysis.

High-Energy Neutrons from the Sandstone Nuclear Bombs as Measured by Threshold Detectors

SS-18

The objective of this experiment was to measure the neutron flux in various energy bands in the Sandstone events. Various types of neutron threshold detectors were deployed at ranges from about 200 to 1,000 yards from GZ. Neutron fluxes for each of the detector types at various ranges are reported.

Neutron Absorption Measurements

SS-19

Integrated dose measurements for high-energy and low-energy neutrons were made in concrete and steel enclosures. These were compared with direct free-field neutron measurements by Los Alamos National Laboratories (SS-18), thereby indicating the neutron-shielding capacity of steel or concrete shelters. The report is an account of the conventional neutron-activation techniques employed to measure the neutron fields and foil activities vs distance from GZ, shielded and unshielded.

Blast Wave Measurements

SS-20, -21, -22

Measurements of blast wave peak pressure and waveform were made using a variety of active and passive instruments. Techniques as unsophisticated as measuring the deformation in metal cans as an indication of pressure magnitude were used. Active displacement gauges were also used for pressure-time measurements. Records of results are provided.

Airplane Shock Wave Measurements

SS-23

Drone B-17 aircraft were flown through the radioactive clouds to collect fission samples from the clouds for bomb diagnostics purposes. Blast and structural response instruments were installed in the aircraft. Pressure transducers and strain gauges were installed on external parts of the airplanes. An accelerometer was positioned at the center of gravity of each aircraft. Successful assessments are reported for shock transit-time between burst point and aircraft, bending moments on aircraft wings from nuclear loads, and aircraft accelerations from nuclear loads. Attempts to measure shock environments failed. Accelerometer and strain gauge data are reported.

Blast Protection Afforded by Structures

SS-24

The Army Corps of Engineers exposed four concrete structures and one earthen barricade at various ranges from X-Ray GZ. Damage to the structures was not extensive, even though they had been moved and tumbled over significant distances. The test hardware and damage are described.

Blast Resistance of Structures

SS-25, -26

The Navy Bureau of Yards and Docks exposed a large number of structures to nuclear blast loads with the objective of developing a model for hardened structure design, 79 units during X-Ray and 92 during Yoke. Typical models were 5 feet on a side and most were constructed of reinforced concrete, with a few of timber or steel. Shapes included cubes, prisms, cylinders, domes, and pyramids with varying wall thicknesses. Some structures were anchored or partially buried. The report describes the response of each test structure and also provides pretest and posttest photographs.

Technical Photography

SS-27, -28

The primary objective of this project was to provide high-speed film coverage of each of the three tests to permit accurate measurements of fireball growth rate for weapon yield determination. Determining early-time shock velocity was also an objective. Two camera platforms, 75 feet high and approximately 5 miles from GZ, were deployed for each test. Excellent film coverage was achieved. SS-28 contains prints illustrating early-time fireball dimensions at various times for Operation Sandstone and for Trinity.

Contamination Studies

SS-30

Numerous studies of radioactivity from nuclear detonations included:

1. Measuring the activity and type of radioactive debris in and around the craters were made.

2. Relating aboveground radioactivity to ground-level radioactivity via posttest (hours and days) aerial surveys to determine if survey aircraft could be employed to plot troop movements through a nuclear battlefield.

3. Measuring activity in the radioactive clouds immediately after the detonation using drone aircraft. Multiple passes were made by the aircraft at various altitudes. Activity measurements inside and outside the aircraft were recorded.

4. Measuring the sizes of radioactive particles of samples from ground and airborne collection devices.

5. Determining the efficiency of a filter system in removing radioactive particles from an air system for bomb shelters.

Radiological Safety Instruments

SS-31

A number of radiation monitors were tested at various locations. Ruggedness was assessed. Monitor readings are compared and reported.

Thermal Effects and Decontamination Studies

SS-32

Material samples were exposed at various distances from nuclear detonations to determine thermal effects, susceptibility to radioactive debris accumulation, and ease of decontamination. Posttest descriptions of samples are reported.

Biological and Animal Container Studies

SS-33

A variety of seeds, insects, and bacteria were exposed to the nuclear bursts to assess the effects of ionizing radiation. Irradiated seeds were to be planted to observe the effects on plant growth. Cage designs for animal exposure in future events were tested.

Nuclear Explosion Detection

SS-34

1. Attempts were made to discover if the light from nuclear explosions could be observed reflecting off the moon. Instruments and personal observations were employed. No reflected light was observed, and no data are reported.

2. Seismic measurements from nuclear detonations were made on islands of the Enewetak Atoll. Accelerometer readings are reported.

3. Attempts to measure perturbations to the earth's magnetic field were made at distances of tens of kilometers from GZ. No signals were noted.