In-flight propulsion system characterization for both Mars Exploration Rover spacecraft
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MER Mars propulsion mission operations performance↗
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Testbed Verification of Pathfinder's Martian Entry, Descent and Lnading (EDL)
Mars Pathfinder is the second spacecraft to be developed as a NASA Discovery mission. Pathfinder employed unique innovations throughout the entire spacecraft that allowed mission development to be accomplished within the 3 year design schedule and $150 million (FY '92 dollars) cost constraint imposed under the Discovery classification.
rover↗
The performance of a winged booster powered by combined rocket and airbreathing propulsion
A conceptual level analysis was performed on a horizontal-takeoff, two-stage-to-orbit system consisting of a rocket and turboramjet powered hypersonic booster and a rocket powered orbiter. The analysis includes estimates of vehicle aerodynamics, performance, and weights. Rocket and airbreathing systems on the booster are operated in parallel and at full thrust for ascent to a Mach 6 staging point, while cruise-back is accomplished using airbreathing propulsion alone. Rocket engines on the orbiter are ignited at staging to propel the orbiter. Booster weights were determined for various combinations of rocket and airbreathing propulsion. The combinations that resulted in the lowest vehicle gross and empty weights were determined. Results show that the lowest gross weight occurs when only airbreathing engines are used. The empty weight of the all airbreathing booster, however, is quite high. Significant reductions in booster empty weight is accomplished with the addition of rocket engines. Also, the use of rockets on the booster greatly decreases the time to staging and the cruise-back distance.
Lepsch, Roger A., Jr.↗
Aeroacoustic Analysis of Fan Noise Reduction With Increased Bypass Nozzle Area
An advanced model turbofan was tested in the NASA Glenn 9-by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) to explore far field acoustic effects of increased bypass nozzle area. This fan stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry (SDT2) which acquired aeroacoustic results over a range of test conditions. The baseline nozzle was sized to produce maximum stage performance at cruise condition. However, the wind tunnel testing is conducted near sea level condition. Therefore, in order to simulate and obtain performance at other operating conditions, two additional nozzles were designed and tested one with +5 percent increase in weight flow (+5.4 percent increase in nozzle area compared with the baseline nozzle), sized to simulate the performance at the stage design point (takeoff) condition, and the other with a +7.5 percent increase in weight flow (+10.9 percent increase in nozzle area) sized for maximum weight flow with a fixed nozzle at sea level condition. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level (OAPWL) reductions of 2 or more dB while the stage thrust actually increased by 2 to 3 percent except for the most open nozzle at takeoff rotor speed where stage performance decreased. Effective perceived noise levels for a 1500 ft engine flyover and 3.35 scale factor showed a similar noise reduction of 2 or more EPNdB. Noise reductions, principally in the level of broadband noise, were observed everywhere in the far field. Laser Doppler Velocimetry measurements taken downstream of the rotor showed that the total turbulent velocity decreased with increasing nozzle flow, which may explain the reduced rotor broadband noise levels.
Woodward, Richard P.↗
Design definition study of NASA/Navy lift/cruise fan V/STOL aircraft. Volume 1: Summary report of Navy multimission aircraft
This report presents results of a study by the Rockwell International Corporation for the NASA Ames Research Center and the Naval Air Systems Command of promising Navy lift-cruise fan V/STOL aircraft for the 1980-1985 time period. The purpose of the study was to identify the likely technical and operating characteristics and technology requirements for the ultimate development of this type aircraft. The study focused on identifying aircraft individually optimized to perform the anti-submarine warfare, carrier onboard delivery, combat search and rescue, surveillance and surface attack missions, and a multi-purpose aircraft concept capable of performing all five missions at minimum total program cost. The configuration features the use of two 1.3 fan pressure ratio, single stage lift-cruise fans and three current design J97 gas generators with a high mounted high aspect ratio wing with winglets. The design missions can be performed at takeoff weights ranging from approximately 32,000 to 39,000 pounds. Top speed is 0.80 Mach number at sea level and 0.885 at altitude, Advanced composite structural technology and advanced subsystem concepts are employed. One basic fuselage design, with alternate bolt-in floor structures, meets all the mission requirements.
Robert L Cavage↗
Evaluating Image Classification Deep Convolutional Neural Network Architectures for Remaining Useful Life Estimation of Turbofan Engines
Accurate estimation of the remaining useful life (RUL) is a key component of condition-based maintenance (CBM) and prognosis and health management (PHM). Data-based models for the estimation of RUL are of particular interest because expert knowledge of systems is not always available, and physical modeling is often not feasible. Additionally, using data-based models, which make decisions based on raw sensor data, allow features to be learned instead of manually determined. In this work, deep convolutional neural network (CNN) architectures are investigated for their ability to estimate the RUL of turbofan engines. To improve the accuracy of the models, CNN architectures, which have proven successful in image classification, are implemented and tested. Specifically, the blocks used in the Visual Geometry Group (VGG) architecture, inception modules used in the GoogLeNet architecture, and residual blocks used in the ResNet architecture are incorporated. To account for varying flight lengths, the input to the models is a window of time series data collected from the engine under test. Window locations at the climb, cruise, and descent stages are considered. To further improve the RUL estimations, multiple overlapping windows at each location are used. This increases the amount of training data available and is found to increase the accuracy of the resulting RUL estimations by averaging the estimates from all overlapping segments. The model is trained and tested using the new Commercial Modular Aero-Propulsion System Simulation (N-CMAPSS) data set, and high prognosis accuracy was achieved. Furthermore, this work expands on the model developed and used in the 2021 PHM Society Data Challenge, which received second place.
convolutional neural networks↗
Application of variable-sweep wings to commuter aircraft
The effects of using variable-sweep wings on the riding quality and mission-performance characteristics of commuter-type aircraft were studied. A fixed-wing baseline vehicle and a variable-sweep version of the baseline were designed and evaluated. Both vehicles were twin-turboprop, pressurized-cabin, 30-passenger commuter aircraft with identical mission requirements. Mission performance was calculated with and without various ride-quality constraints for several combinations of cruise altitude and stage lengths. The variable-sweep aircraft had a gross weight of almost four percent greater than the fixed-wing baseline in order to meet the design-mission requirements. In smooth air, the variable sweep configuration flying with low sweep had a two to three percent fuel-use penalty. However, the imposition of quality constraints in rough air can result in advantages in both fuel economy and flight time for the variable-sweep vehicle flying with high sweep.
Robins, A. W.↗
The Mars Exploration Rover Project
In mid-2003 NASA will launch two identical rovers to mars. The mars exploration rovers will be enclosed in Mars Pathfinder heritage cruise and entry stages.
Mars Exploration Rover Project↗
Optimization of engines for a commercial Mach 0.98 transport using advanced turbine cooling methods
A study was made of an advanced technology airplane using supercritical aerodynamics. Cruise Mach number was 0.98 at 40,000 feet altitude with a payload of 60,000 pounds and a range of 3000 nautical miles. Separate-flow turbofans were examined parametrically to determine the effect of sea-level-static design turbine-inlet-temperature and noise on takeoff gross weight (TOGW) assuming full-film turbine cooling. The optimum turbine inlet temperature was 2650 F. Two-stage-fan engines, with cruise fan pressure ratio of 2.25, achieved a noise goal of 103.5 EPNdB with todays noise technology while one-stage-fan engines, achieved a noise goal of 98 EPNdB. The take-off gross weight penalty to use the one-stage fan was 6.2 percent.
Kraft, G. A.↗
A study to define the research and technology requirements for advanced turbo/propfan transport aircraft
The feasibility of the propfan relative to the turbofan is summarized, using the Douglas DC-9 Super 80 (DS-8000) as the actual operational base aircraft. The 155 passenger economy class aircraft (31,775 lb 14,413 kg payload), cruise Mach at 0.80 at 31,000 ft (8,450 m) initial altitude, and an operational capability in 1985 was considered. Three propfan arrangements, wing mounted, conventional horizontal tail aft mounted, and aft fuselage pylon mounted are selected for comparison with the DC-9 Super 80 P&WA JT8D-209 turbofan powered aircraft. The configuration feasibility, aerodynamics, propulsion, structural loads, structural dynamics, sonic fatigue, acoustics, weight maintainability, performance, rough order of magnitude economics, and airline coordination are examined. The effects of alternate cruise Mach number, mission stage lengths, and propfan design characteristics are considered. Recommendations for further study, ground testing, and flight testing are included.
Goldsmith, I. M.↗
Single stage experimental evaluation of variable geometry inlet guide vanes and stator blading, part 6 Final report
Variable geometry inlet guide vanes and stators for extending stable operation of supersonic cruise turbine engine compressor front stage
Jones, B. A.↗
Strutjet-powered reusable launch vehicles
Martin Marietta and Aerojet are co-investigating the feasibility and viability of reusable launch vehicle designs. We are assessing two vehicle concepts, each delivering 8000 lb to a geosynchronous transfer orbit (GTO). Both accomplish this task as a two-state system. The major difference between the two concepts is staging. The first concept, the two-stage-to-orbit (TSTO) system, stages at about 16 kft/sec, allowing immediate return of the first stage to the launch site using its airbreathing propulsion system for a powered cruise flight. The second concept, the single-stage-to-orit (SSTO) system, accomplishes stage separation in a stable low earth orbit (LEO).
Siebenhaar, A.↗
The Effect of Bypass Nozzle Exit Area on Fan Aerodynamic Performance and Noise in a Model Turbofan Simulator
The design of effective new technologies to reduce aircraft propulsion noise is dependent on identifying and understanding the noise sources and noise generation mechanisms in the modern turbofan engine, as well as determining their contribution to the overall aircraft noise signature. Therefore, a comprehensive aeroacoustic wind tunnel test program was conducted called the Fan Broadband Source Diagnostic Test as part of the NASA Quiet Aircraft Technology program. The test was performed in the anechoic NASA Glenn 9- by 15-Foot Low Speed Wind Tunnel using a 1/5 scale model turbofan simulator which represented a current generation, medium pressure ratio, high bypass turbofan aircraft engine. The investigation focused on simulating in model scale only the bypass section of the turbofan engine. The test objectives were to: identify the noise sources within the model and determine their noise level; investigate several component design technologies by determining their impact on the aerodynamic and acoustic performance of the fan stage; and conduct detailed flow diagnostics within the fan flow field to characterize the physics of the noise generation mechanisms in a turbofan model. This report discusses results obtained for one aspect of the Source Diagnostic Test that investigated the effect of the bypass or fan nozzle exit area on the bypass stage aerodynamic performance, specifically the fan and outlet guide vanes or stators, as well as the farfield acoustic noise level. The aerodynamic performance, farfield acoustics, and Laser Doppler Velocimeter flow diagnostic results are presented for the fan and four different fixed-area bypass nozzle configurations. The nozzles simulated fixed engine operating lines and encompassed the fan stage operating envelope from near stall to cruise. One nozzle was selected as a baseline reference, representing the nozzle area which would achieve the design point operating conditions and fan stage performance. The total area change from the smallest to the largest nozzle was 12.9 percent of the baseline nozzle area. The results will show that there are significant changes in aerodynamic performance and farfield acoustics as the fan nozzle area is increased. The weight flow through the fan model increased between 7 and 9 percent, the fan and stage pressure dropped between 8 and 10 percent, and the adiabatic efficiency increased between 2 and 3 percent--the magnitude of the change dependent on the fan speed. Results from force balance measurements of fan and outlet guide vane thrust will show that as the nozzle exit area is increased the combined thrust of the fan and outlet guide vanes together also increases, between 2 and 3.5 percent, mainly due to the increase in lift from the outlet guide vanes. In terms of farfield acoustics, the overall sound power level produced by the fan stage dropped nearly linearly between 1 dB at takeoff condition and 3.5 dB at approach condition, mainly due to a decrease in the broadband noise levels. Finally, fan swirl angle survey and Laser Doppler Velocimeter mean velocity and turbulence data obtained in the fan wake will show that the swirl angles and turbulence levels within the wake decrease as the fan nozzle area increases, which helps to explain the drop in the fan broadband noise at all fan speeds.
Hughes, Christopher E.↗
BENCAL Cruise Report
This report documents the scientific activities on board the South African Fisheries Research Ship (FRS) Africana during an ocean color calibration and validation cruise in the Benguela upwelling ecosystem (BEN-CAL), 4-17 October 2002. The cruise, denoted Afncana voyage 170, was staged in the southern Benguela between Cape Town and the Orange River within the region 14-18.5 deg E,29-34 deg S, with 15 scientists participat- ing from seven different international organizations. Uniquely in October 2002, four high-precision ocean color sensors were operational, and these included the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on the Aqua and Terra spacecraft, the Medium Resolution Imaging Spectrometer (MERIS), and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). SeaWiFS imagery was transmitted daily to the ship to assist in choosing the vessel's course and selecting stations for bio-optical deployments. There were four primary objectives of the cruise. The first was to conduct bio-optical measurements with above- and in-water optical instruments to vicariously calibrate the satellite sensors. The second was to interrelate diverse measurements of the apparent optical properties (AOPs) at satellite sensor wavelengths with inherent optical properties (IOPs) and bio-optically active constituents of seawater such as particles, pigments, and dissolved compounds. The third was to determine the interrelationships between optical properties, phytoplankton pigment composition, photosynthetic rates, and primary production, while the fourth objective was to collect samples for a second pigment round-robin intercalibration experiment. Weather conditions were generally very favorable, and a range of hyperspectral and fixed wavelength AOP instruments were deployed during daylight hours. Various IOP instruments were used to determine the absorption, attenuation, scattering, and backscattering properties of particulate matter and dissolved substances, while a Fast Repetition Rate Fluorometer (FRRF) was deployed to acquire data on phytoplankton photosynthetic activity. Hydrographic profiling was conducted routinely during the cruise, and seawater samples were collected for measurements of salinity, oxygen, inorganic nutrients, pigments, particulate organic carbon, suspended particulate material, and primary production. Location of stations and times of optical deployments were selected to coincide with satellite overpasses whenever possible, and to cover a large range in trophic conditions.
Hooker, Stanford B.↗
Data from the Development Evolution of a Vehicle for Custom Control
In order to develop custom controllers intended to operate vehicles on a live highway, a series of data collection-focused tests were performed at increasing stages of complexity. Modern vehicles with features like Adaptive Cruise Control (ACC) feature a rich set of sensors and drive-by-wire mechanisms. The presented stages of data collection begins with the analysis of raw data provided by various vehicles, and eventually results in spoofing Controller Area Network (CAN) protocols for sending control commands to operate a vehicle. This paper covers the data and technical efforts needed at various stages. The raw data and tools to plot the data are also publicly available.
99 GENERAL AND MISCELLANEOUS↗
What Is the X-30
The X-30 is envisioned to be a machine that is capable of exploring technology that is critical to single stage to orbit and to hypersonic cruise. The X-30 is comparable to a laboratory that will be able to investigate such things as the chemistry of supersonic combustion and the control of an of an integrated engine airframe, where the forebody of the airplane is the first compression surface for the propulsion. The X-30 is very ambitionous; it follows a path that is pretty well established by such programs as the X-15. This document is limited to a discussion of what is anticipated in the flight tests of the X-30 as opposed to describing the entire vehicle.
Ishmael, Stephen D.↗
NASP technology transfer
It is the stated goal of this program, the National AeroSpace Plane (NASP) program, to develop and then demonstrate the technologies for single-stage-to-orbit flight and hypersonic cruise with airbreathing primary propulsion and horizontal takeoff and landing. This presentation is concerned with technology transfer in the context of the NASP program.
Morris, Charles↗
CFD Evaluation Of Sustainable Aviation Fuel Blends for Commercial Supersonics Technology
An overview is provided of a CFD study on the impacts of fuel blends on NOx emissions and flame structure in an axially staged combustor operating at a supersonic cruise condition. The Open version of the National Combustion Code (OpenNCC) was used to perform two-phase reacting flow computations with various blending ratios of an ‘average’ Jet-A (A2) and Gevo Alcohol-to-Jet (C1) for RTRC’s Axially Controlled Stoichiometry (ACS) combustor. The predicted flame structures in the ACS combustor with three different blending ratios of the A2 and C1 fuel were very similar. The predicted NOx emissions for all fuel blends were within 10% of the experimentally measured range of NOx emissions for 100% A2 fuel.
gas turbine combustion↗