System validation test. LEM crew compartment cooling unit, launch complex 37, launch area B
Lunar excursion module crew compartment cooling system validation test
Roberts, E. H.↗
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Hubble Space Telescope EVA Multisetting Torque Limiter redesign
The Hubble Space Telescope (HST) Multisetting Torque Limiter will be used by astronauts during the First Servicing Mission STS-61. It was designed to replace several individual torque limiters. This replacement reduces the number of tools required as well as reduce the time required for servicing. The Multisetting Torque Limiter design specified five separate torque settings: 2, 5.3, 9, 35 and 45 ft-lbs. This original units were tested at the 2, 5.3, and 9 ft-lbs settings and did not meet the design specifications. The 35 ft-lb and 45 ft-lb torque settings were not incorporated into the original flight design. The objective of the Goddard Space Flight Center (GSFC) redesign effort is to incorporate all five torque settings into a flight design which means the requirements for the first HST Servicing Mission. The first target of the redesign effort focused on the spring chamber and ball detent design. The original design used belleville springs in parallel; the new design changed this configuration to belleville springs stacked in series. The current engineering unit was successfully tested in ambient environment at all five settings. A flight design will soon undergo thermal vacuum testing to evaluate its performance at the temperature extremes.
Richards, Paul W.↗
Selection of Environmentally Friendly Solvents for the Extravehicular Mobility Unit Secondary Oxygen Pack Cold Trap Testing
Freon-113(TradeMark) has been used as a chemistry lab sampling solvent at NASA/JSC for EMU (extravehicular Mobility Unit) SOP (Secondary Oxygen Pack) oxygen testing Cold Traps utilized at the USA (United Space Alliance) Houston facility. Similar testing has occurred at the HSWL (Hamilton Sundstrand Windsor Locks) facility. A NASA Executive Order bans the procurement of all ODS (ozone depleting substances), including Freon-113 by the end of 2009. In order to comply with NASA direction, HSWL began evaluating viable solvents to replace Freon-113 . The study and testing effort to find Freon-113 replacements used for Cold Trap sampling is the subject of this paper. Test results have shown HFE-7100 (a 3M fluorinated ether) to be an adequate replacement for Freon-113 as a solvent to remove and measure the non-volatile residue collected in a Cold Trap during oxygen testing. Furthermore, S-316 (a Horiba Instruments Inc. high molecular weight, non-ODS chlorofluorocarbon) was found to be an adequate replacement for Freon-113 as a solvent to reconstitute non-volatile residue removed from a Cold Trap during oxygen testing for subsequent HC (hydrocarbon) analysis via FTIR (Fourier Transform Infrared Spectroscopy).
Steele, John↗
Single axis reference strapdown inertial measuring unit
Design and tests of single-axis reference strapdown inertial measuring unit
Lee, C. E.↗
Radiation hardness of Efratom M-100 rubidium frequency standard
The effects of nuclear radiation on rubidium gas cell frequency standards and components are presented, including the results of recent tests where a continuously operating rubidium frequency standard (Effratom, Model M-100) was subjected to simultaneous neutron/gamma radiation. At the highest neutron fluence 7.5 10 to the 12th power n/sq cm and total dose 11 krad(Si) tested, the unit operated satisfactorily; the total frequency change over the 2 1/2 hour test period due to all causes, including repeated retraction from and insertion into the reactor, was less than 1 x 10 to the -10th power. The effects of combined neutron/gamma radiation on rubidium frequency standard physics package components were also studied, and the results are presented.
English, T. C.↗
HYPULSE combustor analysis
The analysis of selected data from tests of unit fuel injectors in a generic scramjet combustor model is presented. The tests were conducted in the NASA HYPULSE expansion tube at conditions typical of flight at Mach 13.5 and 17. The analysis used a three-stream tube method, with finite-rate chemistry, in which the fuel, test gas, and mixing/combustive streams were treated independently but with the same static pressure. Performance of three candidate fuel injectors is examined based on deduced mixing and combustion efficiencies.
Rizkalla, O. F.↗
Development of a Battery-Free Solar Refrigerator
Recent technology developments and a systems engineering design approach have led to the development of a practical battery-free solar refrigerator as a spin-off of NASA's aerospace refrigeration research. Off-grid refrigeration is a good application of solar photovoltaic (PV) power if thermal storage is incorporated and a direct connection is made between the cooling system and the PV panel. This was accomplished by integrating water as a phase-change material into a well insulated refrigerator cabinet and by developing a microprocessor based control system that allows direct connection of a PV panel to a variable speed compressor. This second innovation also allowed peak power-point tracking from the PV panel and elimination of batteries from the system. First a laboratory unit was developed to prove the concept and then a commercial unit was produced and deployed in a field test. The laboratory unit was used to test many different configurations including thermoelectric, Stirling and vapor compression cooling systems. The final configuration used a vapor compression cooling cycle, vacuum insulation, a passive condenser, an integral evaporator/ thermal storage tank, two 77 watt PV panels and the novel controller mentioned above. The system's only moving part was the variable speed BD35 compressor made by Danfoss. The 365 liter cabinet stayed cold with as little as 274 watt-hours per day average PV power. Battery-free testing was conducted for several months with very good results. The amount of thermal storage, size of compressor and power of PV panels connected can all be adjusted to optimize the design for a given application and climate. In the commercial unit, the high cost of the vacuum insulated refrigerator cabinet and the stainless steel thermal storage tank were addressed in an effort to make the technology commercially viable. This unit started with a 142 liter, mass-produced chest freezer cabinet that had the evaporator integrated into its inner walls. Its compressor was replaced with a Danfoss DC compressor slightly larger than the one used in the laboratory unit. The control system was integrated onto a single electronics card and packaged with its starting capacitors. The water for thermal storage was placed behind a liner that was made to fit inside the original factory liner. The original condenser was also augmented with additional surface area to improve performance. PV panels with a total rated power of 180 watts were used. The unit was tested with very successful results in an outside ambient environment, demonstrating its potential for widespread use in many off-grid applications for solar refrigeration.
Ewert, Michael K.↗
Integration Test of the High Voltage Hall Accelerator System Components
NASA Glenn Research Center is developing a 4 kilowatt-class Hall propulsion system for implementation in NASA science missions. NASA science mission performance analysis was completed using the latest high voltage Hall accelerator (HiVHAc) and Aerojet-Rocketdyne's state-of-the-art BPT-4000 Hall thruster performance curves. Mission analysis results indicated that the HiVHAc thruster out performs the BPT-4000 thruster for all but one of the missions studied. Tests of the HiVHAc system major components were performed. Performance evaluation of the HiVHAc thruster at NASA Glenn's vacuum facility 5 indicated that thruster performance was lower than performance levels attained during tests in vacuum facility 12 due to the lower background pressures attained during vacuum facility 5 tests when compared to vacuum facility 12. Voltage-Current characterization of the HiVHAc thruster in vacuum facility 5 showed that the HiVHAc thruster can operate stably for a wide range of anode flow rates for discharge voltages between 250 and 600 volts. A Colorado Power Electronics enhanced brassboard power processing unit was tested in vacuum for 1,500 hours and the unit demonstrated discharge module efficiency of 96.3% at 3.9 kilowatts and 650 volts. Stand-alone open and closed loop tests of a VACCO TRL 6 xenon flow control module were also performed. An integrated test of the HiVHAc thruster, brassboard power processing unit, and xenon flow control module was performed and confirmed that integrated operation of the HiVHAc system major components. Future plans include continuing the maturation of the HiVHAc system major components and the performance of a single-string integration test.
Hall propulsion system↗
International Space Station United States Oxygen Generator Development Testing
A life test of a liquid anode feed oxygen generator assembly (OGA) using SPE(R) (United Technologies Corporation, Hamilton Sundstrand Division) membrane technology was terminated in June of 1999. In the total 15,658 hours of operation at MSFC since delivery in 1995, the OGA has produced 2,103 kilograms (kg) (4,632 pounds mass (lbm)) of oxygen, and 263 kg (579 lbm) of hydrogen. Evaluation of cell stack characteristics and oxygen and hydrogen hydrophilic/hydrophobic membrane separators will be discussed.
Erickson, Robert J.↗
Testing of an Annular Linear Induction Pump for the Fission Surface Power Technology Demonstration Unit
Results of performance testing of an annular linear induction pump that has been designed for integration into a fission surface power technology demonstration unit are presented. The pump electromagnetically pushes liquid metal (NaK) through a specially-designed apparatus that permits quantification of pump performance over a range of operating conditions. Testing was conducted for frequencies of 40, 55, and 70 Hz, liquid metal temperatures of 125, 325, and 525 C, and input voltages from 30 to 120 V. Pump performance spanned a range of flow rates from roughly 0.3 to 3.1 L/s (4.8 to 49 gpm), and pressure heads of <1 to 104 kPa (<0.15 to 15 psi). The maximum efficiency measured during testing was 5.4%. At the technology demonstration unit operating temperature of 525 C the pump operated over a narrower envelope, with flow rates from 0.3 to 2.75 L/s (4.8 to 43.6 gpm), developed pressure heads from <1 to 55 kPa (<0.15 to 8 psi), and a maximum efficiency of 3.5%. The pump was supplied with three-phase power at 40 and 55 Hz using a variable-frequency motor drive, while power at 55 and 70 Hz was supplied using a variable-frequency power supply. Measured performance of the pump at 55 Hz using either supply exhibited good quantitative agreement. For a given temperature, the peak in efficiency occurred at different flow rates as the frequency was changed, but the maximum value of efficiency was relative insensitive within 0.3% over the frequency range tested, including a scan from 45 to 78 Hz. The objectives of the FSP technology project are as follows:5 • Develop FSP concepts that meet expected surface power requirements at reasonable cost with added benefits over other options. • Establish a nonnuclear hardware-based technical foundation for FSP design concepts to reduce overall development risk. • Reduce the cost uncertainties for FSP and establish greater credibility for flight system cost estimates. • Generate the key nonnuclear products to allow Agency decision makers to consider FSP as a viable option for potential future flight development. The pump must be compatible with the liquid NaK coolant and have adequate performance to enable a viable flight system. Idaho National Laboratory (INL) was tasked with the design and fabrication of an ALIP suitable for the FSP reference mission. Under the program, a quarter-scale FSP technology demonstration is under construction to test the end-to-end conversion of simulated nuclear thermal power to usable electrical power intended to raise the entire FSP system to Technology Readiness Level 6. An ALIP for this TDU was fabricated under the direction of the INL and shipped to NASA Marshall Space Flight Center (MSFC) for testing at representative operating conditions. This pump was designed to meet the requirements of the TDU experiment. The ALIP test circuit (ATC) at MSFC, previously used to conduct performance evaluation on another ALIP6 was used to test the present TDU pump for the FSP Technology Development program.
Polzin, K. A.↗
Test and evaluation of a multifunction keyboard and a dedicated keyboard for control of a flight management computer
A flight management computer (FMC) control display unit (CDU) test was conducted to compare two types of input devices: a fixed legend (dedicated) keyboard and a programmable legend (multifunction) keyboard. The task used for comparison was operation of the flight management computer for the Boeing 737-300. The same tasks were performed by twelve pilots on the FMC control display unit configured with a programmable legend keyboard and with the currently used B737-300 dedicated keyboard. Flight simulator work activity levels and input task complexity were varied during each pilot session. Half of the points tested were previously familiar with the B737-300 dedicated keyboard CDU and half had no prior experience with it. The data collected included simulator flight parameters, keystroke time and sequences, and pilot questionnaire responses. A timeline analysis was also used for evaluation of the two keyboard concepts.
Crane, J. M.↗
Thermal performance test of the A-2H Apollo Extravehicular Mobility Unit, volume I
Thermal and pressure evaluation testing for Apollo Extravehicular Mobility Unit /EMU/
THERMAL PROTECTION↗
The Powerstick Development
Proof of concept testing has been performed on a 'powerstick' trickle charger, which uses heat from a radioisotope heater unit to charge spacecraft batteries. The type of unit being tested uses a bismuth-telluride thermoelectric converter to produce roughly 40 mW at 15 V. This is much less power than a radioisotope thermoelectric generator (RTG), but the cost and level of environmental concern are also much less.
spacecraft power radioisotope heater unit RHU↗
Design, Development, and Testing of a Water Vapor Exchanger for Spacecraft Life Support Systems
Thermal and environmental control systems for future exploration spacecraft must meet challenging requirements for efficient operation and conservation of resources. Maximizing the use of regenerative systems and conserving water are critical considerations. This paper describes the design, development, and testing of an innovative water vapor exchanger (WVX) that can minimize the amount of water absorbed in, and vented from, regenerative CO2 removal systems. Key design requirements for the WVX are high air flow capacity (suitable for a crew of six), very high water recovery, and very low pressure losses. We developed fabrication and assembly methods that enable high-efficiency mass transfer in a uniform and stable array of Nafion tubes. We also developed analysis and design methods to compute mass transfer and pressure losses. We built and tested subscale units sized for flow rates of 2 and 5 cu ft/min (3.4–8.5 cu m/hr). Durability testing demonstrated that a stable core geometry was sustained over many humid/dry cycles. Pressure losses were very low (less than 0.5 in. H2O (125 Pa) total) and met requirements at prototypical flow rates. We measured water recovery efficiency across a range of flow rates and humidity levels that simulate the range of possible cabin conditions. We measured water recovery efficiencies in the range of 80 to 90%, with the best efficiency at lower flow rates and higher cabin humidity levels. We compared performance of the WVX with similar units built using an unstructured Nafion tube bundle. The WVX achieves higher water recovery efficiency with nearly an order of magnitude lower pressure drop than unstructured tube bundles. These results show that the WVX provides uniform flow through flow channels for both the humid and dry streams and can meet requirements for service on future exploration spacecraft. The WVX technology will be best suited for long-duration exploration vehicles that require regenerative CO2 removal systems while needing to conserve water.
Izenson, Michael G.↗
United States Air Force Wipe Solvent Testing
The Wright-Patterson Air Force Base (WPAFB), as part of the Air Force Material Command, requested that NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) conduct testing and analyses in support of the United States Air Force Wipe Solvent Development Project. The purpose of the wipe solvent project is to develop an alternative to be used by Air Force flight line and maintenance personnel for the wipe cleaning of oxygen equipment. This report provides material compatibility, liquid oxygen (LOX) mechanical impact, autogenous ignition temperature (AIT), and gauge cleaning test data for some of the currently available solvents that may be used to replace CFC-113 and methyl chloroform. It provides data from previous WSTF test programs sponsored by the Naval Sea Systems Command, the Kennedy Space Center, and other NASA programs for the purpose of assisting WP AFB in identifying the best alternative solvents for validation testing.
Hornung, Steven D.↗
Large Area Crop Inventory Experiment (LACIE). Second-generation sampling strategy evaluation report
The author has identified the following significant results. The stratification procedure in the new sampling strategy for LACIE included: (1) correlation test results indicating that an agrophysical stratum may be homogeneous with respect to agricultural density, but not with respect to wheat density; and (2) agrophysical unit homogeneity test results indicating that with respect to agricultural density many agrophysical units are not homogeneous, but removal of one or more refined strata from any such current agrophysical unit can make the strata homogeneous. The apportioning procedure results indicated that the current procedure is not performing well and that the apportioned estimates of refined strata wheat area are often unreliable.
Basu, J. P.↗
Dual laser gyro test program
This paper addresses the results of a comparative test evaluation of two similar-sized but otherwise dissimilar ring laser gyroscopes (RLG's). Both units were tested side by side, with the input axes (IA's) parallel, on the same test table. This report describes the rationale and design factors considered important to the test objectives. Emphasis was placed upon the evaluation of the scale factor (SF) linearity, drift rate stability (short term and long term), and derived rate. Conclusions drawn were (1) that dual operation had an observable but insignificant effect on the test results, (2) that the benefits of dual operation outweighed the additional design and analysis efforts required at the outset of the program, and (3) that the performance characteristics of the two test articles were significantly different. The differences between the two test articles (1) led to suggestions which could direct one vendor toward obtaining improved performance and (2) resulted in the creation of a conceptually new method (DELTA TIME-COUNT histogram) for quickly assessing the quality of laser gyros (or any digital sensor device for that matter).
Jones, Malcolm E.↗
Results of S5 CH tests with an ARL (Aerospace Research Laboratory) cascade
As part of a research agreement between Iowa State University of Science and Technology (ISU) and ONERA, a blade cascade designed and already tested in the United States was manufactured and tested in France. The ONERA cascade wind tunnel and mock-up are described. Attention is focused on defining the upstream conditions of the cascade. Experimental results are presented, as well as comparisons with tests conducted by Detroit Diesel Allison (DDA) in the United States.
Fourmaux, A.↗