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.

From introduction: This report describes the procedures used and the results obtained in evaluating the Wiancko type 3-PBM-2 microbarograph system.

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."

Abstact: "Wind tunnel tests were performed to determine pressure distributions and normal force coefficients on three block forms on mounting planes. The dimension ratios of the blocks were 1:1:1, 1:1:2, and 1:1:4. Results are given for variation in Mach number from 0.066 to 0.8, in Reynolds number from 0.28 x 10(exp 6) to 4 x 10(exp 6), and in yaw angle from 0 to 90 degrees. Results show a Reynolds number independence over the range examined. Windward face force coefficients for a given block form are approximately proportional to the ratio of impact to dynamic pressure. Pressure distribution and resultant coefficients are affected by mounting planes."

Abstract: "An exploding copper wire, one millimeter in diameter, 30 centimeters long, has been developed as a fuse component for a Los Alamos capacitor energy source to be employed in controlled thermonuclear research studies. The fuse allows the passage of the high normal duty "action" (13,700 ampere-coulombs per capacitor) at a 20-second repetition rate. However, it interrupts the circuit to a shorted capacitor in 12 microseconds, thereby protecting the faulted capacitor from explosive energy consumption. The initial phase of the development included observations of various metals (copper, silver, iron, and nickel) as well as various configurations (straight wires, helixes, foils, and tubes). Direct scaling of previous small exploding wire studies at Sandia Corporation was demonstrated with scaling factors up to 700,000."

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.

Abstract: "The pressure drop associated with the flow of air through a cylindrical bed of spherical pebbles has been investigated experimentally. The results of this investigation are reported here."

Abstract: "The excellent agreement between measured boundary layer thickness and thickness calculated by Sivells and Payne recommends their method for calculating turbulent boundary layer growth in axisymmetric hypersonic nozzles. It was thought worthwhile to adapt their approach to the laminar boundary layer. This analysis, along with a limited amount of corroborating data, is presented herein."

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."