Study of explosions in the NASA-MSC Vibration and Acoustic Test Facility /VATF/ Final report
Damage potential of titanium alloy pressure spheres relative to spacecraft vibration testing
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Damage potential of titanium alloy pressure spheres relative to spacecraft vibration testing
An apparatus is under construction for ground-based testing of a gyroscope system to be used in a satellite test of general relativity. The immediate goal is a readout capable of measuring the direction of the gyroscope spin axis to an angular resolution of one arcsecond over a limited range. A combination of SQUID magnetometers and persistent current loops are used to measure the London moment of the spinning superconducting rotor levitated electrostatically. To obtain a trapped flux signal in the gyroscope sufficiently smaller than the London moment signal, the apparatus makes use of a new magnetic field shielding technique for obtaining large superconductor shielded regions below 0.1 millionth of a Gauss.
Nonintrusive diagnostic measurements were performed in the supersonic reacting flow of the Hypersonic Propulsion Test Cell 2 at NASA-Langley. A Coherent Anti-stokes Raman Spectroscopy (CARS) system was assembled specifically for the test cell environment. System design considerations were: (1) test cell noise and vibration; (2) contamination from flow field or atmospheric borne dust; (3) unwanted laser or electrically induced combustion (inside or outside the duct); (4) efficient signal collection; (5) signal splitting to span the wide dynamic range present throughout the flow field; (6) movement of the sampling volume in the flow; and (7) modification of the scramjet model duct to permit optical access to the reacting flow with the CARS system. The flow in the duct was a nominal Mach 2 flow with static pressure near one atmosphere. A single perpendicular injector introduced hydrogen into the flow behind a rearward facing step. CARS data was obtained in three planes downstream of the injection region. At least 20 CARS data points were collected at each of the regularly spaced sampling locations in each data plane. Contour plots of scramjet combustor static temperature in a reacting flow region are presented.
Description of a digital computer control and abort system designed by NASA personnel to control test operations such as rocket engine testing, structure testing, and wind tunnel tests. Because of the nature of spacecraft system testing, particularly rocket engine testing, the unique features of the system are, control function updating at a 20 millisecond rate, continuous abort monitoring, and a software system designed for short duration tests rather than continuous on-line control. The presentation includes a description of the computer system and special interface hardware as well as a general description of the software used.
The paper describes a helium heater to be used to conduct non-nuclear demonstration tests of the complete power conversion loop for a direct-cycle gas-cooled nuclear reactor power plant. Requirements for the heater include: heating the helium to a 1500 F temperature, operating at a 1000 psia helium pressure, providing a thermal response capability and helium volume similar to that of the nuclear reactor, and a total heater system helium pressure drop of not more than 15 psi. The unique compact heater system design proposed consists of 18 heater modules; air preheaters, compressors, and compressor drive systems; an integral control system; piping; and auxiliary equipment. The heater modules incorporate the dual-concentric-tube 'Variflux' heat exchanger design which provides a controlled heat flux along the entire length of the tube element. The heater design as proposed will meet all system requirements. The heater uses pressurized combustion (50 psia) to provide intensive heat transfer, and to minimize furnace volume and heat storage mass.
High level summary of ground test capabilities available at NASA Ames Research Center that can aid in the development and design of future Outer Planet (Saturn and Uranus) probe missions
TREAT operated from 1959-1994, later refurbished & resumed operation in 2017 to support fuel safety testing Zircaloy-clad graphite/fuel blocks comprise core Virtually any power history possible within ~2000 MJ core transient energy capacity From milliseconds to minutes: Pulses, Ramps, LOCA Fuel motion monitoring system “hodoscope” observes fast neutrons emitted from specimens to track fuel relocation in real time Reactor also can be a neutron source to adjacent radiography facility Experiment vehicle does everything else Safety containment, specimen environment, and instrumentation
The Aerospace Corporation has been developing a database of U.S. environmental test laboratory capabilities utilized by the space systems hardware development community. To date, 19 sites have been visited by The Aerospace Corporation and verbal agreements reached to include their capability descriptions in the database. A website is being developed to make this database accessible by all interested government, civil, university and industry personnel. The website will be accessible by all interested in learning more about the extensive collective capability that the US based space industry has to offer. The Environments, Test & Assessment Department within The Aerospace Corporation will be responsible for overall coordination and maintenance of the database. Several US government agencies are interested in utilizing this database to assist in the source selection process for future spacecraft programs. This paper introduces the website by providing an overview of its development, location and search capabilities. It will show how the aerospace community can apply this new tool as a way to increase the utilization of existing lab facilities, and as a starting point for capital expenditure/upgrade trade studies. The long term result is expected to be increased utilization of existing laboratory capability and reduced overall development cost of space systems hardware. Finally, the paper will present the process for adding new participants, and how the database will be maintained.
A fixed-geometry diffuser system was designed for use in Mach 4 free-jet tests of a hydrogen-burning modular scramjet engine. The scramjet engine has a rectangular cross section that blocks up to 33 percent of the existing tunnel nozzle exit area and swept leading edges of the scramjet produce an asymmetric downward flow that sharply increases when the scramjet inlet unstarts. Effects of these conditions on the operation of the diffuser system are not accurately predictable. An experimental investigation has therefore been conducted in unheated air using a subscale model of the tunnel-scramjet-diffuser system to substantiate the design. Test results showed that the preliminary design had to be modified to obtain an acceptable configuration of the nozzle exit, test cabin, and diffuser that would provide shock-free flow at the scramjet inlet for simulated Mach 4 flight at altitudes from 16,764 to 20,422 meters.
One-page descriptions for approximately 200 existing government, university, and industry facilities which may be available in the future to support SEI nuclear propulsion technology development and test program requirements are provided. To facilitate use of the information, the candidate facilities are listed both by location (Index L) and by Facility Type (Index FT). The included one-page descriptions provide a brief narrative description of facility capability, suggest potential uses for each facility, and designate a point of contact for additional information that may be needed in the future. The Nuclear Propulsion Office at NASA Lewis presently plans to maintain, expand, and update this information periodically for use by NASA, DOE, and DOD personnel involved in planning various phases of the SEI Nuclear Propulsion Project.
A modular instrument system is being developed to handle the many data channels encountered in turbojet engine testing. Each module contains a group of transducers and all the signal conditioning multiplexing, and digitizing electronics necessary for direct interface with a digital computer. The digital interface within each module is the same for all modules; in addition, each module provides a controlled environment for its contents. A minicomputer in the control room gathers the data, performs on-line calculation and display, and interfaces with a shared recording and computing system. The advantages of this system are: (1) reduced manpower for system installation, setup, and checkout; (2) standardized equipment interfaces; (3) increased reliability through automatic system testing and minimization of manual adjustments; and (4) reduced cost through minimization of wiring and simplification of control room display.
The RHTF provides the capability to perform multizone, high-temperature radiant testing of large spacecraft TPS and associated structures in a controlled pressure environment to simulate reentry thermal profiles and thermal gradients.
Narrowband analysis revealed grossly similar sound pressure level spectra in each facility. Blade passing frequency (BPF) noise and multiple pure tone (MPT) noise were superimposed on a broadband (BB) base noise. From one-third octave bandwidth sound power analyses the BPF noise (harmonics combined), and the MPT noise (harmonics combined, excepting BPF's) agreed between facilities within 1.5 db or less over the range of speeds and flows tested. Detailed noise and aerodynamic performance is also presented.
The Advanced Stirling Radioisotope Generator (ASRG), a high efficiency generator, is being considered for space missions. An engineering unit, the ASRG engineering unit (EU), was designed and fabricated by Lockheed Martin under contract to the Department of Energy. This unit is currently under extended operation test at the NASA Glenn Research Center (GRC) to generate performance data and validate the life and reliability predictions for the generator and the Stirling convertors. A special test facility was designed and built for the ASRG EU. This paper summarizes details of the test facility design, including the mechanical mounting, heat-rejection system, argon system, control systems, and maintenance. The effort proceeded from requirements definition through design, analysis, build, and test. Initial testing and facility performance results are discussed.
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Contents include the following: James Webb Space Telescope/Integrated Science Instrument Module (JWST/ISIM) Overview. ISIM Thermal Verification Requirements. Emittance Test Objectives. Cryochamber Design Requirements. Cryochamber Construction. Emittance Test Sample Selection and Configuration. Error Sources and Error Mitigation. Cryochamber Operation. Cryochamber and Emittance Sample Test Results.
The development of a reusable space shuttle by NASA in the next decade depends in part on the design of a satisfactory thermal protection system (TPS). The booster and orbiter parts of the shuttle require TPS panels which will withstand thermoacoustic fatigue. The Langley Research Center has begun tests on early panel designs in a new acoustic fatigue facility which is capable of simulating the combined elevated temperature and acoustic environments which these panels are expected to experience. The capabilities of the facility and computer system are outlined, and problems encountered in establishing the test methods are discussed. Tests of a Haynes 25 TPS panel are described, and representative data from tests of the panel at 650 C are included.
A common airfoil model with the CAST 10-2/DOA-2 profile and 228 mm (9 inches) chord length was tested. The tests performed in NAE covered the Mach numbers from 0.3 to 0.8 and Reynolds numbers from 10 to 30 million. The model was tested with transition free and with transition fixed at 5 percent chord for both the upper and the lower surfaces. The data obtained were analyzed for the effects of Reynolds number, transition fixing and Mach number. The role of the boundary layer on the displacement effect, the interaction with the shock wave and the trailing edge separation are examined. The results are summarized as follows: (1) the airfoil performance depends strongly on Reynolds number and transition fixing; (2) with transition fixed, the aerodynamic quantities such as lift, pitching moment and drag show a monotonic variation with Reynolds number; (3) with transition free, the aerodynamic quantities vary less regularly with Reynolds number and a slight parametric dependency is shown. The weak dependency is due to the compensatory effect of the forward shift of the transition position and the thinning of the turbulent boundary layer as Reynolds number increases; (4) the shock Mach number and the shock position are weakly dependent on Reynolds number; and (5) the long extent of the laminar boundary layer at transonic speeds reduces the drag appreciably at low Reynolds numbers. The drag bucket around the design Mach number can be observed below Reynolds number 15 million.