Nuclear Rocket Research Articles

Radiation shielding estimates for manned Mars space flight.

In the analysis of the required radiation shielding protection of spacecraft during a Mars flight, specific effects of solar activity (SA) on the intensity of galactic and solar cosmic rays were taken into consideration. Three spaceflight periods were considered: (1) maximum SA; (2) minimum SA; and (3) intermediate SA, when intensities of both galactic and solar cosmic rays are moderately high. Scenarios of spaceflights utilizing liquid-propellant rocket engines, low- and intermediate-thrust nuclear electrojet engines, and nuclear rocket engines, all of which have been designed in the Soviet Union, are reviewed. Calculations were performed on the basis of a set of standards for radiation protection approved by the U.S.S.R. State Committee for Standards. It was found that the lowest estimated mass of a Mars spacecraft, including the radiation shielding mass, obtained using a combination of a liquid propellant engine with low and intermediate thrust nuclear electrojet engines, would be 500-550 metric tons.

Nuclear Rocket Propulsion - The Past is Prelude

The planning for ambitious manned space missions has renewed interest in nuclear propulsion. During the late 1950s and into the 1970s substantial effort was devoted to nuclear propulsion, primarily...

Computer Music Performance as a Real-Time Testbed

Abstract Traditionally, researchers in real-time think about sophisticated embedded systems such as controllers for nuclear power plants, aircraft and rockets, or robotics. Experimentation in these areas can be impractical, often expensive and potentially deadly. The domain of computer music offers an excellent and inexpensive testbed that exhibits real-time properties. Several features of the language ORE are used to simplify greatly the programming of a MIDI songfile player.

Future spacecraft propulsion

Propulsion requirements for launch vehicles, upper stages, satellites and platforms, and planetary spacecraft are described from a functional perspective and compared on an energy basis. Mission velocity requirements for a range of missions are presented. A simple model relating optimum exhaust velocity and maximum system delta-V as a function of system-specific energy is developed, which provides insight into the relationship between system performance and various power and propulsion subsystem characteristics. Based on this model, various advanced propulsion options, e.g., the solid-core nuclear rocket and nuclear electric propulsion, are evaluated, and the implications of this analysis for propulsion and power system technology development programs are discussed. The objective of this paper is to provide an overview of future propulsion requirements for the nonspecialist.

Nuclear rocket safety

A renewed interest in lunar and Mars exploration and the expanded development of Earth orbiting satellites have resulted in a new interest in nuclear rockets. Well thought-out U.S. and U.N. policies exist for the use of nuclear reactors in space. Guidelines for space reactors have been prepared by DOE and NASA in recent years, and a safety review and approval process is in place. A review of the nuclear rocket program (Rover/NERVA) that was carried on from the mid-fifties until 1973 leads to the philosophy that flight safety considerations should start with the design process and provide solutions that are built into the design. The program resulted in very detailed specifications and criteria for the safe use of rocket reactors. Design practices and an extensive experience base that is still applicable today were developed. This technology base provides important information to be used in any future nuclear rocket as well as the confidence that nuclear rockets can be safely developed for future space missions.

The random force theory applied to regional scale tropospheric diffusion

Twelve examples of long-duration (1- to 50-h) diffusing clouds and plumes, culled from archived data on early nuclear rocket and Plowshare experiments and satellite-observed volcano plumes, are compared individually with a ‘random-force’ theory (Gifford, 1982a, Atmospheric Environment 16, 505–512) of long-range atmospheric diffusion. The resulting fitted curves yield sets of 12 estimates of each of the dynamical parameters of the theory, the Lagrangian integral time-scale of atmospheric turbulence, t L , and the large-scale atmospheric eddy-diffusivity, K, and of other quantities that can be formed from these, such as the lateral turbulent velocity, \\ ̄ gu 2 1 2 the turbulence intensity, i, and the average atmospheric eddy-energy dissipation rate, ε.The Lagrangian time-scale values are all within a factor of about two of the value 10 4 s, confirming the suggestion (Gifford, 1984, Boundary-Layer Met. 30, 159–175) that t L equals the reciprocal of the geostrophic frequency. Stratospheric values of K and ε are an order of magnitude greater than those observed within the troposphere. Values of other quantities are more scattered but yield, in each instance, reasonable averages.

Authors

Authors

Perfect steady-state tracking and disturbance rejection by constant state feedback

Abstract A new interpretation and solution of the linear multivariate steady-state tracking and disturbance rejection problem is presented. On condition of reference and disturbance input variables with constant final values the proposed method prepares the ground for the calculation of a constant feedback control law, which meets the steady-state requirements exactly, although doing without the conventional prefilter or integral feedback respectively. Nevertheless the practical design reduces to the standard problem of stabilizing a precontrolled system by fictitious constant output feedback. The method is illustrated by the examples of a fourth-order nuclear rocket engine and a twelfth-order chemical absorption column.

Gaseous-Fuel Reactor Systems for Aerospace Applications

Research on the gaseous fuel nuclear rocket concept continues under the programs of the U.S. National Aeronautics and Space Administration (NASA) Office for Aeronautics and Space Technology and now includes work related to power applications in space and on earth. In a cavity reactor test series, initial experiments confirmed the low critical mass determined from reactor physics calculations. Recent work with flowing UF6 fuel indicates stable operation at increased power levels. Preliminary design and experimental verification of test hardware for high-temperature experiments have been accomplished. Research on energy extraction from fissioning gases has resulted in lasers energized by fission fragments. Combined experimental results and studies indicate that gaseous-fuel reactor systems have significant potential for providing nuclear fission power in space and on earth.

Temperature-viscosity induced laminar instabilities in a gaseous heated channel

Laminar flow instability exhibits itself as a flow rate excursion in single isolated tubes having negative pressure-drop-flow-rate derivative at constant heat addition in a gas which has a viscosity increasing with temperature in the laminar Reynolds number range. An application is in laminar flow nuclear rocket reactors. The constitutive equations for such a system were solved using seven different forms of the energy equation in a steady state isolated channel. An equation for flow rate at neutral stability is given. Parametric results are presented for a range of heat flux, flow rate and fluid state conditions. Closed form solutions and existing experimental findings were verified using numerical analysis.

Physics and potentials of fissioning plasmas for space power and propulsion

Fissioning uranium plasmas are the nuclear fuel in conceptual high temperature gaseous core reactors for advanced rocket propulsion in space. A gaseous core nuclear rocket would be a thermal reactor in which an enriched uranium plasma at about 10,000°K temperature is confined in a reflector-moderator cavity where it is nuclear critical and transfers its fission power to a confining propellant flow for the production of thrust at a specific impulse up to 5000 sec. With a thrust-to-engine weight ratio approaching unity, the gaseous core nuclear rocket could provide for propulsion capabilities needed for manned missions to the nearby planets, and for economical cis-lunar ferry services. Fueled with enriched uranium hexafluoride and operated at temperatures lower than needed for propulsion, the gaseous core reactor scheme also offers significant benefits in applications for space and terrestrial power. They include high efficiency power generation at low specific mass, the burnup of certain fission products and actinides, the breeding of 233U from thorium with short doubling times, and improved convenience of fuel handling and processing in the gaseous phase.

Transversely excited submillimeter-wave waveguide laser

Gaseous core reactors and nuclear pumped lasers have the potentials of space propulsion at exhaust jet velocities up to 50,000 m/sec, space power at 1 kg/kW specific mass, power transmission via laser beams over astronomical distances and beneficial applications on Earth.The energization of lasers directly by nuclear reactions has recently been achieved. In experiments conducted jointly by the University of Florida and the Los Alamos Scientific Laboratory, New Mexico, a helium-xenon laser was directly pumped by fission fragments. The obtained laser wavelength was 3.5 μm. A group of researchers at the Sandia Corporation in Albuquerque, New Mexico, was successful in energizing a carbon monoxide laser by fission fragments at wavelengths in the 5-μm band. At the University of Illinois lasing was achieved at wavelengths of 8629 Å and 9393 Å in a neon-nitrogen mixture. A program of gaseous core reactor research is underway with experiments being conducted at the Los Alamos Scientific Laboratory in New Mexico, USA. The program utilizes a beryllium moderator-reflector, forming a cylindrical cavity of 1 m diameter and 1 m length. This system and associated control system hardware, uses components from the previous ROVER nuclear rocket program. Various configurations of canisters containing enriched gaseous uraniumhexafluoride fuel are inserted into the reactor cavity for research on neutronics and nuclear induced optical radiation.Critical mass, control swing and the effects of poison were measured by simulating enriched uranium hexafluoride fuel with uranium foils, which were placed in homogenous and inhomogeneous distributions in the cavity. Critical mass was determined at about 6 kg 93% enriched 235 uranium. A uranium hexafluoride canister system was built for safe operation in the reactor cavity and for physics measurements and observations at nuclear criticality.It is anticipated that this work will result in the demonstration of principles of a new type of nuclear power reactor, and of laser power output from such a reactor.

LUNCHEON ADDRESS: INCREASING THE PRODUCTIVITY OF THE DEFENSE ESTABLISHMENT THROUGH AUTOMATION

LUNCHEON ADDRESS: INCREASING THE PRODUCTIVITY OF THE DEFENSE ESTABLISHMENT THROUGH AUTOMATION

Dynamics and control with a nuclear rocket engine

Dynamics and control with a nuclear rocket engine

Author List

Author List

Linear programming design of multivariable feedback controllers for the NERVA nuclear engine

The application of Linear Programming (LP) to the design of state variable feedback controllers for multivariable plants with known deterministic inputs is described. The design problem is solved in two steps. The first step consists of an open-loop optimization in which LP is used to determine the plant input vector profile which optimizes the plant response to a specified demand. The second step, also implemented by LP, produces the controller parameters (a matrix of constant gains) and consists of an optimum fitting, through the feedback controller, of the input and feedback error vector profiles determined in the first step. The performance criterion used is the minimum Integral Weighted Absolute Value (IWAV). The technique is illustrated with an application to the NERVA nuclear rocket engine controller design.

Comparison of Advanced Propulsion Capabilities for Future Planetary Missions

This paper summarizes unmanned planetary performance (payload and trip time) of Shuttle-based advanced propulsion systems for 1980-90 missions analyzed as part of the recent NASA/AEC Advanced Propulsion Comparisons Studies. Propulsion system designs and condensed results from over 300 propulsion/mission combinations are discussed. Chemical rocket (CRP), solar electric (SEP), nuclear rocket (NRP), and nuclear electric (NEP) propulsion systems are all considered. In terms of missions flown, total flight time, and number of Shuttle launches required, NEP provides the best performance. Relative to NEP, it is shown that NRP, SEP, and CRP degrade mission performance by 20%, 40%, and 50%, respectively, at nominal payloads.

A Psychosocial Approach to the Peking Opera

Studies of the popular theatre of Japan show that an understanding of it can provide insights into some of the prevailing life themes and of the conflicts of the people with the mechanisms they use to cope with them. A better knowledge of the inhabitants of the People's Republic of China is very much needed by the outside world. The authors, therefore, have analyzed examples of the classical Peking Opera, which were presented in China until about 1965, when, as a result of the Cultural Revolution, the emphasis and some of the techniques of the traditional drama were altered and some new subject matter was added. They point out, however, that in the modern revolutionary Peking Opera the essential form was changed remarkably little. The conclusions reached are the following ones. The Chinese seek to temporize conflicts and to search for nonviolent solutions. They seem to make an all-out effort to obtain reconciliation that does not cause either party to lose face. Life and death decisions are made slowly and only after time and trouble has been taken to look at many sides of an issue and then the decisions are person-centered rather than situation-centered. The possible implications of these conclusions on the relations of nations with the People's Republic of China are pointed out. In an earlier article [1] we pointed out how an understanding of the popular theatre of Japan could provide insights into some of the prevailing life themes and of the conflicts of the Japanese people with the persistent mechanisms used by them to cope with them. More than thirty years ago, David Snedden of Teacher's College, Columbia University, recommended that American secondary schools teach Russian and Japanese, because they were key languages of the future [2]. He was right as far as he went but he overlooked Chinese. If we were to predict the course of events for the remainder of this century, we would say that the Chinese language also be given the same priority. The People's Republic of China (P.R.C.) is a nation with an uninterrupted civilization going back several thousand years. It now embraces twenty to twenty-five per cent of the population of the Earth. Since its revolution in 1949, its development of nuclear power and rocket missiles and its admission to the United Nations has made it a pivot in the balance of power among nations. The antiquity of the Chinese is comparable to that of the Jews. Their history affords them a kind of security in attacking the future. The Chinese until the revolution of 1949, like Jews, placed their * President, Institute for Advanced Studies in the Theatre Arts, 310 West 56th Street, New York, NY 10019, U.S.A. (Received 27 July 1973.) ** Formerly Dean of Training, Postgraduate Center for Mental Health, New York, N.Y., U.S.A. Died 22 January 1973. main emphasis upon the past. Ancestor worship and strong family tradition convinced them that nothing new ever happened in the present or would happen in the future. But in post-revolution China, as in Israel, a greater sense of the future follows on a greater sense of the past. Parallels are often misleading. Yet they can sometimes illuminate. China in the Far East might be considered to have played the role of ancient Greece in the West. Throughout their long history the Chinese generally believed that their civilization would prevail without resort to invasion, war or imperialisitic colonizing. The traditional self-view of the Chinese that they are the chosen people leads an outsider who does not really understand this attitude to feel that they are indifferent to others [3]. The view that the Chinese are the chosen people is not unlike that of the Jews. The Chinese took their country to be the center of the world and those who were not Chinese were considered barbarians. The history of China since the 1800's is filled with examples of culture shock on the part of the Chinese, with astonishment by the fact that peoples other than Chinese had the ability to invent, to achieve. An Occidental myth is that the Oriental is insensitive. The Chinese are in fact not easy to understand. It is difficult to get Chinese to talk about themselves and about their country. It seems unlikely that the Chinese can be expected to teach Occidentals about China and its people. Therefore, insight must be sought from other sources. It is

Buoyancy Effect on Fuel Containment in a Gas-Core Nuclear Rocket

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.

Crew Radiation Dose from a High-Impulse Gas-Core Nuclear Rocket Plume

Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.