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At least 919 records · Page 51

Biconic cargo return vehicle with an advanced recovery system

The current space exploration initiative is focused around the development of the Space Station Freedom (SSF). Regular resupply missions must support a full crew on the station. The present mission capability of the shuttle is insufficient, making it necessary to find an alternative. One alternative is a reusable Cargo Return Vehicle (CRV). The suggested design is a biconic shaped, dry land recovery CRV with an advance recovery system (ARC). A liquid rocket booster will insert the CRV into a low Earth orbit. Three onboard liquid hydrogen/liquid oxygen engines are used to reach the orbit of the station. The CRV will dock to the station and cargo exchange will take place. Within the command and control zone (CCZ), the CRV will be controlled by a gaseous nitrogen reaction control system (RCS). The CRV will have the capability to exchange the payload with the Orbital Maneuvering Vehicle (OMV). The bent biconic shape will give the CRV sufficient crossrange to reach Edwards Air Force Base and several alternative sites. Near the landing site, a parafoil-shaped ARS is deployed. The CRV is designed to carry a payload of 40 klb, and has an unloaded weight of 35 klb.

Source record↗

Fast Paced, Low Cost Projects at MSFC

What does an orbiting microsatellite, a robotic lander and a ruggedized camera and telescope have in common? They are all fast paced, low cost projects managed by Marshall Space Flight Center (MSFC) teamed with successful industry partners. MSFC has long been synonymous with human space flight large propulsion programs, engineering acumen and risk intolerance. However, there is a growing portfolio/product line within MSFC that focuses on these smaller, fast paced projects. While launching anything into space is expensive, using a managed risk posture, holding to schedule and keeping costs low by stopping at egood enough f were key elements to their success. Risk is defined as the possibility of loss or failure per Merriam Webster. The National Aeronautics and Space Administration (NASA) defines risk using procedural requirement 8705.4 and establishes eclasses f to discern the acceptable risk per a project. It states a Class D risk has a medium to significant risk of not achieving mission success. MSFC, along with industry partners, has created a niche in Class D efforts. How did the big, cautious MSFC succeed on these projects that embodied the antithesis of its heritage in human space flight? A key factor toward these successful projects was innovative industry partners such as Dynetics Corporation, University of Alabama in Huntsville (UAHuntsville), Johns Hopkins Applied Physics Laboratory (JHU APL), Teledyne Brown Engineering (TBE), Von Braun Center for Science and Innovation (VCSI), SAIC, and Jacobs. Fast Affordable Satellite Technology (FastSat HSV01) is a low earth orbit microsatellite that houses six instruments with the primary scientific objective of earth observation and technology demonstration. The team was comprised of Dynetics, UAHuntsvile, SAIC, Goddard Space Flight Center (GSFC) and VCSI with the United States Air Force Space Test Program as the customer. The team completed design, development, manufacturing, environmental test and integration in one year. FastSat HSV01 also deployed a Poly Picosatellite Orbital Deployer (PPOD) for a separate nano ]satellite class spacecraft (Cubesat: Nano Sail Demonstration) in partnership with Ames Research Center. The Robotic lunar lander is a MSFC JHU APL partnership that led to the development of a flexible architecture for landers to support robotic missions to a wide range of lunar and asteroid destinations. The team started with the goal of meeting NASA agency directives that led to the creation of a test bed focusing on GN&C and software to demonstrate the descent and landing on any airless body for the final 30 to 60 meters. The team created a complex technology demonstration as well as Guidance Control and Navigation (GN&C) algorithms providing autonomous control of the lander. The team uses a green propellant of 90% hydrogen peroxide and has completed 18 successful test flights. The International Space Station (ISS) SERVIR Environmental Research and Visualization System (ISERV) is a technology demonstration payload to assist the SERVIR project with environmental monitoring for disaster relief and humanitarian efforts. The ISERV project was a partnership with TBE. The ISERV payload consists of a commercial off the shelf camera, telescope, and MSFC developed power distribution box and interfaces on ISS with the Window Observational Research Facility in the US Lab. MSFC has identified three key areas that enabled the low cost mission success to include culture, partnering, and cost/schedule control. This paper will briefly discuss these three Class D efforts, FastSat HSV-01, the Robotic Lunar Lander and the ISERV camera system, the lessons learned, their successes and challenges.

Watson-Morgan, Lisa↗

Structural design feasibility study of Space Station long spacer truss

The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.

Armand, Sasan C.↗

Optical Fiber Illumination System for visual flight simulation

An electronically controlled lighting system simulating runway, aircraft carrier, and landing aid lights for flight simulations is described. The various colored lights that would be visible to a pilot by day, at dusk, or at night are duplicated at the distances the lights would normally become visible. Plastic optical fiber illuminators using tungsten halogen lights are distributed behind the model. The tips of the fibers of illuminators simulating runway lights are bevelled in order that they may be seen from long distances and at low angles. Fibers representing taxiway lights are pointed and polished for omni-directional visibility. The electronic intensity controls, which can be operated either manually or remotely, regulate the intensity of the lights to simulate changes in distance. A dichronic mirror, infrared filter system is used to maintain color integrity.

Hollow, R. H.↗

Computational Investigation of Powered Descent for Human-Scale Mars Landers

NASA human-scale Mars entry, descent, and landing vehicles currently under consideration have system requirements beyond the current state of the art. Specifically, heritage approaches for deceleration using parachutes and initiating engines at subsonic speeds are not adequate to land these large vehicles (50-60 metric ton entry mass) precisely (within 50 meters of a surface target). Therefore, the present approach for landing humans on Mars utilizes entry vehicles with large aerodynamic surface areas that transition to the descent and landing phase by initiating retropropulsion at supersonic speeds. Vehicle performance, including stability and control, depends on accurate characterization of the aerodynamic-propulsive interference effects, especially at engine initiation, when the vehicles are transitioning from an entry attitude to that suitable for descent and landing. This paper summarizes the human Mars entry vehicle configurations, retropropulsion integration, performance assumptions, and expected flight environment at engine initiation. Cases spanning supersonic, transonic, and subsonic conditions during powered descent are analyzed using four computational fluid dynamics codes, all of which have been previously applied to supersonic retropropulsion at varying scales and conditions. The results of the analysis are used to develop an aerodynamic-propulsive interference model that has since been applied in trajectory simulations to augment the fidelity of human-scale Mars entry vehicle performance.

Ashley M Korzun↗

A Streamlined Approach to Spatial Mapping of Complex 3D Thermal Boundary Condition Data

Spatial mapping of 1D, 2D, and particularly 3D thermal boundary condition data is essential for accurate thermal simulation of spacecraft and launch vehicles. This information typically is available in simple ASCII file format but can be problematic to use for thermal simulations. Difficulties that can be encountered include the ability to directly use the available file format, transformation of the data into the desired reference coordinate system in 3D space, and accurate interpolation of the data onto the thermal calculation domain. This paper presents a streamlined approach to spatial mapping of complex unsymmetrical 3D cold wall heat flux data using the fields’ capability in Simcenter3D. A recent example of 3D thermal plume simulation at MSFC will be employed to illustrate the use of text, csv, and Excel files, specifying coordinate systems for transformation of data in 3D space, and use of the various interpolation schemes available for spatial mapping. Spatial boundary condition verification is also very important, and the spacecraft thermal analyst needs effective visualization tools to develop confidence in the boundary condition definitions. Visualization of the spacecraft plume raw field data, the calculated field data, and the interpolated field data onto the thermal calculation domain will be discussed, with a particular focus on real-time viewing of the interpolated data for available interpolation schemes. The objective of this paper is to outline the modeling techniques used with the integrated thermal analysis of a terrestrial lunar lander demonstrator. Specifically, the techniques outlined herein focus on spatial mapping of convective and radiative exhaust plume results from a computational fluid dynamics (CFD) analysis. Two cases were investigated, however, the modeling techniques that were utilized translate to both cases seamlessly. Those two cases were as follows: • Lunar lander demonstrator firing on-pad (worst case). • Lunar lander demonstrator hovering at an elevated position above the launch pad. For the purposes of information control, this paper will focus on the modeling techniques only, using altered or dimensionless data where necessary. BACKGROUND The thermal model examined in this paper is of the lunar lander demonstrator known as XL-1T (terrestrial), born from a collaborative effort between Masten Space Systems (MSS) and NASA, under NASA’s Lunar CATALYST (also known as Lunar Cargo Transportation and Landing by Soft Touchdown) initiative. The lander is a reusable vertical takeoff/vertical landing (VTVL) test bed which is controlled by four throttleable main engines utilizing green hypergolic propellants.

Hawkins, Robert F.↗

Noise data for a twin-engine commercial jet aircraft flying conventional, steep, and two-segment approaches

Center-line noise measurements of a twin-engine commercial jet aircraft were made during steep landing approach profiles, and during two-segment approach profiles for comparison with similar measurements made during conventional approaches. The steep and two-segment approaches showed significant noise reductions when compared with the -3 deg base line. The measured noise data were also used to develop a method for estimating the noise under the test aircraft at thrust and altitude conditions typical of current landing procedures and of landing procedures under development for the Advanced Air Traffic Control System.

Hastings, E. C., Jr.↗

A Ganymede lander mission

The paper addresses the dynamical problem and question of technical feasibility associated with delivering a simple, semi-hard lander to one of the Galilean satellites, Ganymede. Emphasis is placed on the identification of a viable, not necessarily optimal, baseline trajectory and maneuver sequence. Simplicity is stressed in the lander's use of two fixed-impulse solid rockets for landing maneuvers. It is shown through an error analysis that navigation and maneuver execution errors can be compensated on the baseline descent trajectory by controlling just the thrust direction. Finally, specific subsystem capabilities needed on the lander to achieve a successful touchdown within a specific performance envelope are also identified.

Boain, R. J.↗

Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 1: Europe, July 1980

The development and implementation of aircraft noise control regulations in various European states are described. The countries include the United Kingdom, France, Switzerland, Federal Republic of Germany, Sweden, Denmark, and the Netherlands. Topics discussed include noise monitoring, airport curfews, land use planning, and the government structure for noise regulation.

Spencer, F. A.↗

Limited evaluation of an F-14A airplane utilizing an aileron-rudder interconnect control system in the landing configuration

A flight test was conducted for preliminary evaluation of an aileron-rudder interconnect (ARI) control system for the F-14A airplane in the landing configuration. Two ARI configurations were tested in addition to the standard F-14 flight control system. Results of the flight test showed marked improvement in handling qualities when the ARI systems were used. Sideslip due to adverse yaw was considerably reduced, and airplane turn rate was more responsive to pilot lateral control inputs. Pilot comments substantiated the flight data and indicated that the ARI systems were superior to the standard control system in terms of pilot capability to make lateral offset corrections and heading changes on final approach.

Kelley, W. W.↗

Takeoff and Landing of Transport Aircraft

Computer program provides detailed analysis of takeoff and landing performance capabilities of transport-category aircraft. Performance calculated according to airworthiness standards of Federal Aviation Regulations. Program used to investigate advanced takeoff procedures for noise alleviation, such as programed throttle and control flaps.

Foss, W. E.., Jr.↗

Software requirements: Guidance and control software development specification

The software requirements for an implementation of Guidance and Control Software (GCS) are specified. The purpose of the GCS is to provide guidance and engine control to a planetary landing vehicle during its terminal descent onto a planetary surface and to communicate sensory information about that vehicle and its descent to some receiving device. The specification was developed using the structured analysis for real time system specification methodology by Hatley and Pirbhai and was based on a simulation program used to study the probability of success of the 1976 Viking Lander missions to Mars. Three versions of GCS are being generated for use in software error studies.

Withers, B. Edward↗

Preliminary Flight Results of a Fly-by-throttle Emergency Flight Control System on an F-15 Airplane

A multi-engine aircraft, with some or all of the flight control system inoperative, may use engine thrust for control. NASA Dryden has conducted a study of the capability and techniques for this emergency flight control method for the F-15 airplane. With an augmented control system, engine thrust, along with appropriate feedback parameters, is used to control flightpath and bank angle. Extensive simulation studies were followed by flight tests. The principles of throttles only control, the F-15 airplane, the augmented system, and the flight results including actual landings with throttles-only control are discussed.

Burcham, Frank W., Jr.↗

Regional Assimilation of NASA Atmospheric Infrared Sounder (AIRS) Data

The NASA Short-term Prediction Research and Transition (SPORT) Center seeks to accelerate the infusion of NASA Earth Science Enterprise (ESE) observations, data assimilation and modeling research into NW S forecast operations and decision-making. The Atmospheric Infrared Sounder (AIRS), is expected to advance climate research and weather prediction into the 21 st century. It is one of six instruments onboard Aqua, a satellite that is part of NASA s Earth Observing System. AIRS, along with two partner microwave sounding instruments, represents the most advanced atmospheric sounding system ever deployed in space. The system is capable of measuring the atmospheric temperature in the troposphere with radiosonde accuracies of 1 K over 1 km-thick layers under both clear and cloudy conditions, while the accuracy of the derived moisture profiles will exceed that obtained by radiosondes. It is imperative that the scientific community is prepared to take full advantage of next-generation satellite data that will become available within the next decade. The purpose of this paper is to describe a procedure designed to optimally assimilate AIRS data at high spatial resolution over both land and ocean. The assimilation system used in this study is the Local Analysis and Prediction System (LAPS) developed at the Forecast System Laboratory used extensively around the globe. Results will focus on quality control issues associated with AIRS, optimal assimilation strategies, and the impact of the AIRS data on subsequent numerical forecasts at 12 km produced by the next generation Weather Research and Forecast (WRF) model.

Chou, Shih-Hung↗

Investigation of the Effectiveness of Dynamic Seat in a Black Hawk Flight Simulation

Low cost alternatives have been sought to provide motion cues in ground-based flight simulators to meet mission objectives. The ability to provide high frequency vibrations makes the dynamic seat attractive to helicopter training applications. Previous studies have found that dynamic seat does enhance the realism of the cockpit and affect pilots' workload. This investigation, conducted under the auspices of the Joint Shipboard Helicopter Integration Process (JSHIP), is using a three degree-of-freedom dynamic seat, i.e., heave, surge, and sway, with limited travels in a research simulator configured as a UH-60 Black Hawk at NASA Ames Research Center. The seat's effectiveness is studied using hover, landing, pirouette, bob-up/bob-down, sidestep, and acceleration/deceleration maneuvers. Seat commands consist of constant vibrations in heave and sway which provide the fundamental vibratory cues. Pilot station accelerations and collective controls provide onset and sustained commands. In addition, transient effects due to translational-lift, collective; and normal acceleration are produced by regulating the magnitude and frequency that depend on the rotor rpm. Results are compared to flight test data and two other ground-based motion systems configurations, i.e., a motion condition with very large motion travels and a motion condition that is comparable with commercial simulator travels. Both subjective and objective data will be analyzed to determine the significance of the motion cueing effect in each system for selected maneuvers.

Chung, William W. Y.↗

Fine Particulate Matter Predictions Using High Resolution Aerosol Optical Depth (AOD) Retrievals

To date, spatial-temporal patterns of particulate matter (PM) within urban areas have primarily been examined using models. On the other hand, satellites extend spatial coverage but their spatial resolution is too coarse. In order to address this issue, here we report on spatial variability in PM levels derived from high 1 km resolution AOD product of Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm developed for MODIS satellite. We apply day-specific calibrations of AOD data to predict PM(sub 2.5) concentrations within the New England area of the United States. To improve the accuracy of our model, land use and meteorological variables were incorporated. We used inverse probability weighting (IPW) to account for nonrandom missingness of AOD and nested regions within days to capture spatial variation. With this approach we can control for the inherent day-to-day variability in the AOD-PM(sub 2.5) relationship, which depends on time-varying parameters such as particle optical properties, vertical and diurnal concentration profiles and ground surface reflectance among others. Out-of-sample "ten-fold" cross-validation was used to quantify the accuracy of model predictions. Our results show that the model-predicted PM(sub 2.5) mass concentrations are highly correlated with the actual observations, with out-of- sample R(sub 2) of 0.89. Furthermore, our study shows that the model captures the pollution levels along highways and many urban locations thereby extending our ability to investigate the spatial patterns of urban air quality, such as examining exposures in areas with high traffic. Our results also show high accuracy within the cities of Boston and New Haven thereby indicating that MAIAC data can be used to examine intra-urban exposure contrasts in PM(sub 2.5) levels.

aerosol optical depth↗

Full-Scale Crash Tests and Analyses of Three High-Wing Single

The NASA Emergency Locator Transmitter Survivability and Reliability (ELTSAR) project was initiated in 2014 to assess the crash performance standards for the next generation of ELT systems. Three Cessna 172 aircraft have been acquired to conduct crash testing at NASA Langley Research Center's Landing and Impact Research Facility. Testing is scheduled for the summer of 2015 and will simulate three crash conditions; a flare to stall while emergency landing, and two controlled flight into terrain scenarios. Instrumentation and video coverage, both onboard and external, will also provide valuable data of airframe response. Full-scale finite element analyses will be performed using two separate commercial explicit solvers. Calibration and validation of the models will be based on the airframe response under these varying crash conditions.

Annett, Martin S.↗