Misty Castle: High-Explosive Nuclear Effects Simulations at White Sands Missile Range

Misty Castle IV: Misty Picture (1987)

Date: 14 May 1987
Location: Permanent High-Explosive Test Site (PHETS), White Sands Missile Range
Explosive Charge: 4,685 tons, ANFO

Objectives

Primary Objective: Provide an airblast, dust cloud, and ground shock environment for DoD-sponsored experiments.

Secondary Objective: Provide a thermal and airblast environment for relevant experiments.

By the Numbers

Event Summary

“Misty Picture was a high-explosive test sponsored by the Defense Nuclear Agency. It was detonated at 1000 hours on 14 May 1987. The explosive charge consisted of 4,685 tons of ANFO poured in bulk into a 44-foot radius, 88-foot diameter, fiberglass hemisphere, similar to the one used for Minor Scale, the previous test in the Misty Castle series of high-explosive nuclear simulations at White Sands Missile Range.”

“The primary objective of the test was to provide an airblast, dust cloud, and ground shock environment for DoD-sponsored experiments. These experiments were designed to determine the response of tactical and strategic weapon systems, communications equipment, vehicles, and a variety of structures to this environment. A secondary objective was to provide a thermal environment (in addition to airblast) for several experiments.

The principal experiment governing the size of the event was the Ballistic Reentry Vehicle (BRV) fly-through experiment. This experiment required a dust cloud environment large enough to test the BRV. Another major experiment was the simulated precursor environment which was used to verify the response of various Hardened Mobile Launcher (HML) models.”

“Initial technical support plans were submitted to [the Defense Nuclear Agency] starting in May 1985. The first project officers’ meeting was held in July 1985, the second in September 1985. With the success of the 8-kiloton Minor Scale event and a strong requirement to increase the yield for the next large-scale high-explosive test, plans to expand the test site to accommodate a 16-kiloton [explosion] for Misty Picture were initiated. Hydro code calculations were performed for a 16-kiloton event. Airblast and ground shock predictions were made for the larger event. Many experimenters were planning for the larger event, but in December 1985, when the project with the strong requirement for a 16-kiloton event decided to cancel its participation on Misty Picture, the yield was reduced to 8 kilotons.”

The test was conducted at White Sands Missile Range, approximately 20 miles south of the northern boundary at the Permanent High Explosive Test Site (PHETS). Ground zero was 500 feet south/southeast of the Minor Scale ground zero from 1985. This location allowed for the reuse of nearby roads, instrumentation parks, instrumentation radials, and most of the diagnostic camera bunkers.

“The [explosive charge container] was a segmented fiber-glass hemisphere 44 feet in radius. The base of the hemisphere consisted of 24 identical segments and the top consisted of 12 segments… Individual segments were erected by a special hydraulic fixture, bolted together, and sealed with an additional quarter-inch fiberglass patch on the inner and outer surfaces along each joint.”

The process of filling the container with ANFO was very similar to that used in the Minor Scale test: “4,685 tons of ANFO were loaded into the 88-foot diameter, honeycombed, fiberglass hemisphere. The ANFO was delivered to the test site in bulk form from the mixing plant in hopper trucks. At ground zero, the ANFO was pneumatically discharged into the hemisphere. Two workmen inside the hemisphere, wearing self-contained breathing apparatus, distributed the ANFO to ensure uniform distribution. This process continued until loading was terminated. The entire loading operation required approximately 10 days to complete.”

“The precursor simulated effects of a thermal ground layer on blast wave propagation. The thermal flash from a nuclear device heats the ground and surface air faster and creates a precursor on the shockwave near the surface of the ground. The precursor simulated this environment by providing a two-foot-high layer of helium gas contained beneath eight mylar envelopes. Since pressure waves advance faster in helium than in air, the shockwave moved faster in the helium environment and produced a simulated precursor. The first envelope began 404 feet from ground zero. The ground surface beneath the envelopes was covered with one to three inches of specially prepared dust.”

“Four Talos/Terrier missiles and 20 Viper rockets were to be fired into the dust cloud produced by the Misty Picture detonation during the T+1 minute to T+3 minute time period. The missile payloads are ballistic re-entry vehicles being tested for the effects of dust erosion on their surfaces and trajectories. The rockets were samplers to define the environment that the re-entry vehicles were exposed to. The Vipers were fired in volleys of four, before and after each Talos/Terrier firing (five volleys of four).” The first stage of the Talos launch vehicle was planned to fall short of the Misty Picture testbed. The second stage and ballistic re-entry vehicle would continue through the dust cloud, climbing to a maximum altitude of 41,000 feet MSL. The second stage of the Talos would separate and fall to the south of ground zero. The ballistic re-entry vehicle would separate and return to earth via parachute.

Approximately 200 experiments, sponsored by ten US agencies and four foreign governments, were planned for Misty Picture. The United Kingdom, Canada, Norway, and Sweden were the foreign countries participating. Like Minor Scale, the test included a number of classified experiments. The total cost of the experiments was approximately $60 million USD. Site preparation, instrumentation, and logistical support cost approximately $18 million USD. The planned 4,880 tons of ANFO cost $0.9 million USD.