Materials technology program for a compact fast reactor for space power
Production engineering and compatibility tests of Ta-8W-2Hf clad UN nuclear fuel element for use in lithium cooled space power unit reactors
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Production engineering and compatibility tests of Ta-8W-2Hf clad UN nuclear fuel element for use in lithium cooled space power unit reactors
Dry heat spacecraft sterilization-compatibility tests of reagents and growth media for planetary biological exploration
Results of compatibility tests between tungsten and hyperstoichiometric uranium carbide alloys run at 1800 C for 1000 and 2500 hours. These tests compared tungsten-buffered uranium carbide with tungsten-buffered uranium-zirconium carbide. The zirconium carbide addition appeared to widen the homogeneity range of the uranium carbide, making additional carbon available for reaction. Reaction layers could be formed by either of two diffusion paths, one producing UWC2, while the second resulted in the formation of W2C. UWC2 acts as a diffusion barrier for carbon and slows the growth of the reaction layer with time, while carbon diffusion is relatively rapid in W2C, allowing equilibrium to be reached in less than 2500 hours at a temperature of 1800 C.
Results of chemical compatibility tests between both pure tungsten and thoriated tungsten run at 1800 C for up to 3300 hours with uranium carbide alloys. Alloying with zirconium carbide appeared to widen the homogeneity range of uranium carbide, making additional carbon available for reaction with the tungsten. Reaction layers were formed both by vapor phase reaction and by physical contact, producing either or both UWC2 and W2C, depending upon the phases present in the starting fuel alloy. Formation of UWC2 results in slow growth of the reaction layer with time, while W2C reaction layers grow rapidly, allowing equilibrium to be reached in less than 2500 hours at 1800 C. Neither the presence of a thermal gradient nor the presence of thoria in the tungsten clad affect the reactions observed.
The results obtained in an inlet-engine compatibility test run in the 10x10 SWT of the NASA-Lewis Research Center are reviewed. This program was run to measure the time-variant distortions produced in a supersonic inlet and to relate a unique distortion peak, occurring in an instant of time, to the origin of stall in a compressor. The major stumbling block in this type of effort is the determination of a proper increment of time over which to average pressures before computing distortions. It is reasonable to expect that the proper averaging time is related to the particular compressor in question. The most significant point reported is that the proper averaging time may not be solely dependent on a particular compressor, and, in fact, may vary with operating conditions, even for the same inlet-engine combination.
Dynamic distortion data obtained from inlet engine compatibility test on a J85-GE-13 engine are used to establish the feasibility of using on-line generated indices as control signals. These data are analyzed over time increments of 1.3 seconds on an analog computer. The analog program of four instantaneous distortion indices and their results are presented. A modified approach in determining the extent of distortion is also presented.
The mission plan of the docking of a United States Apollo and a Soviet Union Soyuz spacecraft in Earth orbit to test compatible rendezvous and docking equipment and procedures is presented. Space experiments conducted jointly by the astronauts and cosmonauts during the joint phase of the mission as well as experiments performed solely by the U.S. astronauts and spread over the nine day span of the flight are included. Biographies of the astronauts and cosmonauts are given.
The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.
New-generation recorder/reproducers are being installed in the Pre/Post-Detection Recording Subsystem at DSSs 14 (Goldstone), 43 (Australia), 63 (Spain), and the JPL Compatibility Test Area CTA 21. The performance of these new-generation machines is discussed, and representative corroborating data acquired at CTA 21 are presented.
Dish-mounted latent heat storage subsystems for Rankine, Brayton, and Stirling engines operating at 427 C, 816 C, and 816 C respectively are discussed. Storage requirements definition, conceptual design, media stability and compatibility tests, and thermal performance analyses are considered.
A numerical method for simultaneously and efficiently coupling an external subsonic potential flow and an interior viscous flow such that the two flows match at an interfacing boundary is discussed. Both a panel method and a simple point compressible vortex model are used for the outer potential field. The interior flow solvers which were used are the Navier-Stokes and Euler codes of T. J. Coakley and the Euler code of A. Verhoff. In order to test compatibility, the panel method is coupled to the less expensive Euler codes since the coupling procedure is identical with the Navier-Stokes code. The results show significant efficiency improvements can be obtained over the uncoupled approach. Results also indicate the outer potential flow is best represented by the simple point compressible vortex model. The panel method couples smoothly to Coakley's implicit code but is numerically incompatible as coupled with the explicit Euler code. An improved Navier-Stokes code is under initial development which extends the Euler code to include the necessary viscous terms. Results are shown for all infinite length channel with one wavy periodic wall with and without laminar separation.
Compatibility increased by fluorination. Report describes experiments aimed at improving compatibility of some fluorinated elastomers with high-pressure oxygen. Such elastomers needed for seals, gaskets, and positive-expulsion devices used with high-pressure oxygen. Oxygen - compatibility tests carried out on five elastomers chosen on the basis of literature survey.
The Jet Propulsion Laboratory is investigating the possibility of developing advanced electrochemical techniques as accelerated compatibility tests for metal/propellant systems which overcome the problems associated with the low conductivity of the liquid propellants (e.g., hydrazines, nitrogen tetroxide). Both DC techniques and AC electrochemical impedance spectroscopy are being evaluated. Progress has been made in experiments involving stainless steel with hydrazine and nitrogen tetroxide propellants.
The German Telecommunications Satellite (DFS) Program is to provide telecommunications service for high data rate transmission of text and video data to the Federal Republic of Germany within the 11-14 GHz and 20-30 GHz bands. The space segment of this program is composed of three satellites, DFS-1, DFS-2, and DFS-3, which will be located at 23.5 degrees E longitude of the geostationary orbit. The DFS will be launched from the Center Spatial Guyanis in French Giana on an Ariane launch vehicle. The mission follows the typical injection sequence: parking orbit, transfer orbit, and earth orbit. Attitude maneuvers will be performed to orient the spacecraft prior to Apogee Kick Motor (AKM) firing. After AKM firing, drift phase orbital and attitude maneuvers will be performed to place the spacecraft in its final geostationary position. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. Information is presented in tabular form for the following areas: DSN support, compatibility testing, frequency assignments, telemetry, command, and tracking support responsibilities.
The primary objective of the Goldstone Solar System Radar is the investigation of solar system bodies by means of Earth-based radar. Targets of primary interest include the Galilean moons, Saturn's rings and moons, and Earth-approaching asteroids and comets. Planets are also of interest, particularly Mercury and the planets to which NASA has not yet planned spacecraft visits. Based on a history of solid achievement, including the definition of the Astronomical Unit, imaging and topography of Mars, Venus, and Mercury, and contributions to the general theory of relativity, the program will continue to support flight project requirements and its primary objectives. The individual target objectives are presented, and information on the following topics are presented in tabular form: Deep Space Network support, compatibility tests, telemetry, command, and tracking support responsibility.
The Mars Observer Mission will deliver a single spacecraft to Mars for an extended orbital study of the planet's surface, atmosphere, and gravitational and magnetic fields. A flight profile is given, and information is presented in tabular form on the following topics: Deep Space Network support; compatibility tests, frequency assignments, telemetry, command, and tracking support responsibility.
A testbed for flight and ground systems compatible with the Consultative Committee for Space Data Systems (CCSDS) Recommendations has been developed at NASA's Goddard Space Flight Center. The subsystems of an end-to-end CCSDS based data system are being developed. All return link CCSDS telemetry services (except Internet) and both versions of the CCSDS frame formats are being implemented. In key areas of uncertainty, multiple design approaches are being performed. In addition, key flight-qualifiable hardware components, such as Reed-Solomon encoders, are being developed to complement the testbed element development. The testbed and its capabilities are described. The method of dissemination of the testbed results are given, as are plans to make the testbed capabilities available to outside users. Plans for the development of standardized conformance and compatibility tests are provided.
During this annual progress report time period, the following activities took place: (1) Generation of several versions of the CELIAS (STOF/SEM/CTOF/MTOF/DPU) commissioning timeline for the first 180 days after launch. These were written and submitted by A. Galvin after consultation (phone, fax, e-mail, meetings) with the CELIAS Instrument Manager and Lead-Co-I's. (2) Identification of several problems with the CELIAS portion of the Project Data Base (PDB). (3) Meetings with the Flight Operations Team regarding PDB, critical commands, etc. (4) Attend Science Operations Working Group (SOWG) Meetings (November 1994, February 1995, May 1995) and Flight Operations Review Meeting (July 1995). (5) Participate in Flight Operation Simulations SIM 1 (November 14-18, 1994), SIM 2 (May 1-4, 1995) and SIM3 (August 7-11, 1995). (6) Participate in the Ground System Compatibility Test Rehearsal (April 24- 28, 1995), GSCT #2 (May 30-June 14, 1995), GSCT #3 (September 12-22, 1995), and GSCT #4b (October 30-November 5, 1995). A small portion of the documentation for the above cited activities is appended.