This report documents the design, development, and performance of the flight vehicle for Re-entry Flight Demonstration Number One (RFD-1).

Craters were observed resulting from square arrays of 64-pound charges at various spacings and depths. The closest spacings yielded craters very like those from single 256-pound charges, while wider spacings yielded craters more or less square in shape and with a mound or pier at the center. Generally, the areas so uncovered were greater than for single 256-pound charges, except for very deep charges. Volumes, too, were enhanced by this configuration by as much as a factor of three. If the same factor is maintained for nuclear charges, the cost per unit volume of a crater from such an array will be within 20 percent of that for a single charge.

This report on the RFD-1 optical data and external fuel-element experiment includes a description of the instruments and test components used, a presentation of the data obtained, an explanation of the methods of data reduction employed, and a statement of the conclusions derived. It covers the theory, design, qualification tests, flight-test data, and results of the external fuel-element experiment. Also presented is a theoretical analysis of observed versus predicted ablation times and altitudes for the external fuel elements. In addition, this report presents recommendations for improvements to data acquisition and reduction methods in future, similar flight tests.

Re-entry flight demonstration number one (RFD-1) was launched on May 22, 1963 from the Scout launch complex at NASA Wallops Station, Wallops Island, Virginia.

Forword: The International Symposium for Packaging and Transportation of radioactive materials held at Albuquerque, New Mexico, January 12 to 15, 1965, was a joint effort on the part of the Sandia Corporation, the Albuquerque Operations Office, and the Headquarters, U.S. Atomic Energy Commission.

Abstract: RFD-2 was the second of Sandia's operational safety flight tests of systems for nuclear auxiliary power.

Abstract: This report describes the SNAP-10A Simulated Test Reactor, the test philosophy of Re-entry Flight Demonstration Number One, the analytical analysis of reactor disassembly, and the results of the flight test.

Abstract: This report constitutes the RFD-1 Safety Flight Plan for investigating the disassembly, distraction, and disposal of the SNAP-10A reactor during re-entry.

Abstract: This report presents a summary and brief evaluation of the RFD-2 flight-test data reduced as of December 16, 1964.

The experiment described herein has shown that the concept of low dams produced by ballistic collision of ejecta from simultaneous detonation of properly spaced parallel rows of charges is a feasible one. Rows of 8-pound charges were buried 3 feet deep with 4-foot spacing between charges. When two such rows of charges were placed parallel and 17.5 feet apart, the maximum height of the "dam" was achieved. The spacing of 17.5 feet between rows corresponds to 4.7 times the crater radius of one 8-pound charge at the burial depth which maximizes the single-charge crater. The extrapolation of these results to larger explosions is discussed. The height decreases and the width increases as the spacing between rows is further increased. The mass of material in the "dam" cannot exceed that in the crater of one of the rows. At the spacing between rows which maximizes height, the volume of the "dam'' is about 50 percent of maximum volume theoretically achievable. At wider spacings, the volume increases to 75 percent.

Introduction: The purpose of this report is to describe a mathematical model which will help solve the ultimate-particle-size problem by estimating the evaporative mass losses during that portion of re-entry when the fuel is in liquid form.

Abstract: "Available data on wind persistence and wind forecasting capability have been applied in estimating the probability of a fallout pattern shifting from an uninhabited safe sector into a populated region. Safety probability is computed from win variability, forecasting accuracy, initial height and particle size of radioactivity landing at a point in the predicted fallout pattern, predicted wind speed, length of forecast period, and safe-sector angular width."

Abstract: "Wind observations collected at Yucca Flat since 1951 are analyzed for timewise variability. Variability functions of altitude, season, wind speed, and vector wind are described. Derived variability parameters are incorporated into calculations of fallout safety probability for NTS operations."

From scope of work: This report investigates the dynamic characteristics of sealed military type relays as affected by applied coil voltage and/or current, temperature, spring tension, contact force, contact overtravel, and mechanical clearances.

From abstract: Many residents of the Nevada area carried film badge radiation dosimeters during Operation Plumbbob in 1957. Badge readings in specific localities appear to follow the logarithmic-normal distribution.

From summary: This report concerns the theoretical evaluation and experimental development of special thermocouples capable of being accurately located at or near the surface of metal structures to permit measurement of temperature distribution through the strictures.

Abstract: "Weights of linear high-explosive charges fired on the Yucca Lake playa of the Nevada Test Site varied from 0.23 to 42.7 pounds per foot. Crater and ditch dimensions and volumes resulting from these shots, fired during the fall of 1959 and spring of 1960, are presented here as a function of charge burst depths. Scaling relationships determined are as expected; i.e., square-root scaling of linear-charge weight per foot for ditch width and depth and a direct linear-charge weight relationship to ditch volume are obtained. Permanent ground surface displacement varies as the -3.22 power of the scaled distance from the charge. Detonation effects, charge shape effects, ditch erosion, and ditch cross sections are discussed. The appendixes present Toboggan data, results of soil investigation, and mathematical treatment given the data."

Abstract: "This report discusses tests conducted to determine the accuracy of meteorological equipment which is used to gather upper air data. Equipment tested was the GMD-2, SMD-1A, GMD-1B, and the WBRT-57. A four-station phototheodolite network was used as a standard for point-in-space determinations."

Abstract: "Spherical charges of TNT, each weighing 256 pounds, were exploded at various depths in tuff to determine apparent crater dimensions in a soft rock. No craters were obtained for depths of burst equal to or greater than 13.3 feet. It was deduced that rock fragments were sufficiently large that charges of greater magnitude should be employed for crater experiments intended as models of nuclear explosions."

Abstract: "This report presents the characteristics incorporated in the design of a ballistic rocket system that is capable of carrying recoverable payloads varying in weight from 75 to 200 pounds to altitudes of 600,000 to 1,000,000 feet (msl)."

This report describes the Sandia Corporation participation and results related to Project Buckboard: the detonation of three 40,000-pound and ten 1000-pound high-explosive charges in basalt rock to establish depth -of-burst curves.

From preface: The work described in this document is directed toward determining the optimum method of employing explosives to form a ditch, channel, or canal of certain desired dimensions.

Abstract: "A scale-model experiment was made to check the application of charge spacing rules developed from earlier studies to terrain of randomly varying elevation. Since a prominent possible peacetime use of nuclear explosives is the excavation of a trans-Isthmian canal, the model used was a portion of such a route. The experiment resulted in nearly the desired linear crater dimensions; the spacing rules developed for level trerain give a satisfactory channel when applied to terrain with elevations varying in random fashion."

Partial abstract: "This report is based: (1) on information developed in earlier high explosive experiments which determined the optimum spacing and burial depth of charges in a row to produce a channel uniformly wide and deep, and (2) on the Sedan and Danny Boy experiments, which provided data on dimensions of nuclear craters in both soil and basalt rock. This information has been combined with the 1947 route surveys of the Panama Canal company, and estimates have been made not only of the number and yield of nuclear explosives required to excavate a Transisthmian canal with nuclear explosives, but also of the cost of the explosives and the cost of their replacement."