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Technical Paper

A Building for Testing European Rovers and Landers under Simulated Surface Conditions: Part 1 - Design and Phasing

2008-06-29
2008-01-2021
Europe has embarked on a new programme of space exploration involving the development of rover, lander and probe missions to visit planets, moons and near Earth objects (NEOs) throughout the Solar System. Rovers and landers will require testing under simulated planetary, and NEO conditions to ensure their ability to land on and traverse the alien surfaces. ESA has begun work on a building project that will provide an enclosed and controlled environment for testing rover and lander functions such as landing, mobility, navigation and soil sampling. The facility will first support the European ExoMars mission due for launch in 2013. This mission will deliver a robotic rover to the Martian surface. This paper, the first of several on the project, gives an overview of its design configuration and construction phasing. Future papers will cover its applications and operations.
Technical Paper

A CFD-Based, Application-Oriented, Integrated Simulation Environment for Rapid Prediction of Aerodynamic Sensitivities of 3-D Configurations

1997-10-01
975606
Within the frame of a series of initiatives aimed at improving effectiveness of its aircraft design and analysis capabilities, the Military Division of Daimler-Benz Aerospace (Dasa) is developing MIDAS, a multidisciplinary integration framework for a suite of numerical codes suitable to quickly and still accurately assess aircraft performance. As MIDAS specifically targets support of configurational studies in a Conceptual and Preliminary Design environment, peculiar requirements such as scope, range of applicability, and robustness of the system components, reliability of results, care-free operability, and fast response times have to be properly addressed.
Technical Paper

A CIRA 3D Ice Accretion Code for Multiple Cloud Conditions Simulations

2023-06-15
2023-01-1461
This work presents the implementation and validation efforts of a 3D ice accretion solver for aeronautical applications, MESS3D, based on the advanced Messinger model. The solver is designed to deal with both liquid phase and ice crystal cloud conditions. In order to extend the Messinger model to 3D applications, an algorithm for the water run-back distribution on the surface was implemented, in place of an air flow stagnation line search algorithm, which is straightforward in 2D applications, but more complicated in 3D. The developed algorithm aims to distribute the run-back water in directions determined by air pressure gradients or shear forces. The data structure chosen for MESS3D allows high flexibility since it can manage the necessary input solutions on surface grids coming from both structured and unstructured solvers, regardless the number of edges per surface cells.
Technical Paper

A Canopy Model for Plant Growth Within a Growth Chamber: Mass and Radiation Balance for the Above Ground Portion

1991-07-01
911494
As humans move into outer space, need for air, clean water and food require that green plants be grown within all planetary colonies. The complexities of ecosystems require a sophisticated understanding of the interactions between the atmosphere, all nutrients, and life forms. While many experiments must be done to find the relationships between mass flows and chemical/energy transformations, it seems necessary to develop generalized models to understand the limitations of plant growth. Therefore, it is critical to have a robust modelling capability to provide insight into potential problems as well as to direct efficient experimentation. Last year we reported on a simple leaf model which focused upon the mass transfer of gases, radiation/heat balances, and the production of photosynthetically produced carbohydrate. That model indicated some of the plant processes which had to be understood in order to obtain parameters specific for each species.
Technical Paper

A Case Study of Stormwater Runoff Containing Deicing / Anti-icing Fluids Treatment at DFW Airport

2003-06-16
2003-01-2123
Airline tenants at Dallas/Fort Worth International Airport (DFW Airport) use deicing/anti-icing chemicals, as may be needed, to maintain wintertime operations. DFW Airport has implemented best management practices for pollution prevention measures relating to deicing/anti-icing activities. However, as the planes leave the deicing pads, deicing/anti-icing fluids can drip from the planes onto the runways, taxiways, and ramp areas. As planes take off, the fluids can also shear off onto Airport property. During winter storm events, these deicing/anti-icing fluids are flushed off the runways, etc., with the stormwater. Stormwater containing deicing/anti-icing fluids can discharge through outfalls into Trigg Lake located in the southwestern part of the DFW Airport property.
Technical Paper

A Comparative Study Between Different Psychological Approaches During an ESA Space Simulation

1994-06-01
941358
The objectives are to compare different psychological methods used to assess the evolution of the interrelations inside the crew and the relationships between the crew and the outside in a sixty days isolation/confinement's simulation. After presenting each method, results are compared. The discussion try to point out if these methods are equivalent or if they are complementary. The specificity of each method is shown and conclusions try to associate some methods with specific scientific goals.
Technical Paper

A Comparative Study of Turbulence Models in Axisymmetric Nozzle Flow

1995-05-01
951440
Two turbulence models have been studied to determine which of the models should be used in further Computational Fluid Dynamics (CFD) research. A zero-equation turbulence model, Baldwin-Lomax (B-L), is easy to use, requires no history of the flow, and requires little in the way of additional computations or additional computer memory space [1]. A two-equation k-ε model, Yang-Shih (Y-S), is more difficult to implement, does require flow history, and requires many more computations and much more computer space; however, it is potentially more accurate than the B-L model [2]. Using both Navier-Stokes (NS) and Parabolized Navier-Stokes (PNS) solvers, the two models and their codes were validated against the testbed of the Wright Laboratory (WL) Mach 12 wind tunnel nozzle.
Technical Paper

A Comparison of Numerical Techniques for the Study of Lightning Indirect Effects

2001-09-11
2001-01-2894
A comparison of various numerical tools and techniques was performed for calculating the lightning indirect effects to composite structures and internal systems. This paper is a summary of the initial comparison results. Detailed results of each technique considered are given in additional separate papers presented during this conference. The modeling considered current distributions over and within composite surfaces and the coupling of current and voltages to internal systems such as wire bundle cables and hydraulic and fuel tubes. The models were compared to each other and to measured data from low level swept continuous wave (LLCW) tests performed on two test fixtures. Other features of the codes such as run time, ease of use, computer requirements, availability of documentation and technical support, etc. are compared as well.
Journal Article

A Comparison of the Apollo and Early Orion Environmental Control, Life Support and Active Thermal Control System's Driving Requirements and System Mass

2008-06-29
2008-01-2081
The Orion Crew and Service Modules are often compared to the Apollo Command and Service Modules due to their similarity in basic mission objective: both were dedicated to getting a crew to lunar orbit and safely returning them to Earth. Both spacecraft rely on the environmental control, life support and active thermal control systems (ECLS/ATCS) for the basic functions of providing and maintaining a breathable atmosphere, supplying adequate amount of potable water and maintaining the crew and avionics equipment within certified thermal limits. This assessment will evaluate the driving requirements for both programs and highlight similarities and differences. Further, a short comparison of the two system architectures will be examined including a side by side assessment of some selected system's hardware mass.
Technical Paper

A Comprehensive Numerical Model for Numerical Simulation of Ice Accretion and Electro-Thermal Ice Protection System in Anti-icing and De-icing Mode, with an Ice Shedding Analysis

2023-06-15
2023-01-1463
This work presents a comprehensive numerical model for ice accretion and Ice Protection System (IPS) simulation over a 2D component, such as an airfoil. The model is based on the Myers model for ice accretion and extended to include the possibility of a heated substratum. Six different icing conditions that can occur during in-flight ice accretion with an Electro-Thermal Ice Protection System (ETIPS) activated are identified. Each condition presents one or more layers with a different water phase. Depending on the heat fluxes, there could be only liquid water, ice, or a combination of both on the substratum. The possible layers are the ice layer on the substratum, the running liquid film over ice or substratum, and the static liquid film between ice and substratum caused by ice melting. The last layer, which is always present, is the substratum. The physical model that describes the evolution of these layers is based on the Stefan problem. For each layer, one heat equation is solved.
Technical Paper

A Computer Aided Engineering Tool for ECLS Systems

1987-07-01
871423
This paper presents an overview of the Computer Aided Systems Engineering and Analysis (CASE/A)-ECLSS series which is designed as a generalised ECLSS design and analysis package. This system was developed under NASA MSEC contract NAS8-36407 to meet the Systems Analysis requirements of the Space Station ECLSS. The Space Station represents an order of magnitude increase in complexity over current Spacecraft technologies and will seriously tax current analysis techniques. This program is capable of simulating atmospheric revitalization systems, water recovery and management systems, and single phase active thermal control systems. The program evolved from both the G189A and the SINDA programs and shares the G189A architectural concepts. The designer/ analysis interface is graphics based and allows the designer to build a model by constructing a schematic of the system under consideration.
Technical Paper

A Computer Technique to Evaluate Routing of Fluid System Plumbing for Aircraft Engines

1967-02-01
670584
In the design of fluid systems plumbing for aircraft engines, the designer is continually challenged by the problem of component location and routing. In order to achieve accessibility and maintainability, and to avoid physical interferences, plumbing design is accomplished through extensive graphical projection and mockups. The solution to this problem must also satisfy tubing stress limits, resonant frequencies, bracket or clamping positions available and future space requirements. To facilitate and expedite this design procedure a digital computer technique has been developed which determines the clearances between tubing and other engine components. Though not a substitute for graphical projection, this program provides a means for accurate checking for interference. It also serves a valuable purpose in the storage of previous or alternate plumbing routing arrangements for comparison.
Technical Paper

A Concept for a Manned Artificial Gravity Research Ship

1992-07-01
921192
In the first half of the next century, Mankind will expand its sphere of existence to the Moon and space, and they will stand on Mars and study the other planets. Then, humans will inevitably be required to live for long periods, two years or more, in micro-gravity and/or low gravity environments. However, it is well known that such micro or low gravity environments adversely affect human physiology and psychology. The longer the period the greater such effects are and these can result in serious health problems. To improve living conditions in space by generating artificial gravity will be important to solving these problems.
Technical Paper

A Configurable Solid State Power Management and Distribution System

2002-10-29
2002-01-3210
Future vehicle power systems must achieve greater flexibility and reliability than those used in previous generations. New functions that enhance safety, such as arc detection and wiring integrity verification, are essential for new systems. Embedded autonomous control, and fault correction can be built into Fault Tolerant Processors that integrate into a vehicle Open System Architecture. This approach will provide status and fault detection information to maintenance interfaces and provide fault correction. Safety is enhanced by the prevention of dangerous restarts from crew and personnel. The embedded features allow for pre-flight mission configuration to setup systems before takeoff and on-board and off-board maintenance control. This enables operators to evaluate power system health and history to help reduce turn around time.
Journal Article

A Continuing Investigation of Diurnal and Location Trends in an Ice Crystal Icing Engine Event Database

2019-06-10
2019-01-1964
Due to ongoing efforts by the aviation industry, much has been learned over the last several years regarding jet engine power loss and compressor damage events caused by the ingestion of high concentrations of ice crystal particles into the core flow path. Boeing has created and maintained a database of such ice crystal icing (ICI) events to aid in analysis and further study of this phenomenon. This article provides a general update on statistics derived from the Boeing event database, and provides more details on specific event clusters of interest. A series of three flight campaigns have, over the past five years, collected in-situ data in deep convective clouds that will be used for the assessment of the new FAA CFR Part 33 ice crystal environmental envelope Appendix D, and the equivalent EASA CS-25 Appendix P.
Technical Paper

A Cooperative Launch Optimization Technique Using the Flight Design System

1986-10-01
861650
An optimization technique has been developed on the Flight Design System (FDS) which examines available target and instrument constraints to determine an optimal target launch time for maximum instrument viewing in a cooperative launch scenario. By definition, a cooperative launch is a coordinated mission between an orbiting viewing instrument and a target which is launched from the ground at a time specified by instrument viewing requirements. The technique is designed to evaluate instrument constraints such as range and slewing rate limitations and analyze them parametrically with the relative target launch time to determine the effect on the instrument viewing period. Using the FDS, this technique can be utilized in a real-time situation by updating the instrument's position and re-evaluating applicable parameters to obtain an updated target launch time.
Technical Paper

A Crawling Portable Robot for Drilling Operations in Large Air Frame Components

2005-01-03
2005-01-3337
The system that will be presented consists of a Crawling Portable Robot (CPR) for drilling large air frame components as a part of the whole assembly process of fuselage or wing type sub-structures. Currently, the drilling of such components is massively fulfilled manually in a very labour intensive and “craft-based” manner. The operations are conducted in cramped, dangerous conditions and often involve unhealthy postures. The alternative to this situation consists in the use of large fixed-base multi-axis machines mounted upon a foundation on the shop floor. These machines are quite expensive, and also have a number of operational limitations. Because of their large working envelope, it is difficult for these machines to hold close tolerances over the entire range of all movement axes of the machine. Hence, there is a need to probe and calibrate the machine to the workpiece one or more times during work operations with the consequent negative impact in productivity.
Technical Paper

A Database Containing Operational Experience in Spaceflight

1991-07-01
911499
Throughout the manned-space programs of the National Aeronautics and Space Administration (NASA), significant data has been gathered regarding how humans live and work in the environment encountered in space. Recording operational experience helps avoid duplication of errors, can improve the design of equipment and procedures, and can provide valuable insight into human-machine and human-environment interfaces. Several sources contain valuable information about living and working in space, but are in an uncoordinated paper format. A relational database, called the Operational Experience Database, has been constructed to electronically store and organize human factors information from the Skylab and Space Shuttle missions. The taxonomy used to organize this database builds on the one used for the Skylab human-machine experiments. This information can be used by NASA engineers and operations personnel to remedy design problems, or expand on design successes.
Technical Paper

A Description and Comparison of U.S. and Russian Urine Processing Hardware for the International Space Station

1994-06-01
941251
The Russian space program has maintained crews on long duration space flights nearly continuously over the past two decades. As a result, a strong emphasis has been placed on the development of regenerative life support systems. One of these systems is a urine processor which has been operating on-orbit since 1990. The U. S has also been developing urine processing systems to reclaim water from urine over the past twenty years. This paper will describe the two different technologies used for urine processing for long-term human presence in space and will compare the operating characteristics of the two systems.
Technical Paper

A Discussion and Demonstration of Some Characteristics of an Advanced HLA/RTI Environment for Aerospace Applications

2016-10-25
2016-36-0282
Modeling and Simulation - M&S is recently gaining more importance and emphasis as an essential method for developing engineering systems especially for aerospace and automotive systems, due to their complexity, integration and even human involvement. The main reasons for M&S having that important role nowadays are: 1) M&S can predict system behavior and possible problems. Therefore, it can reduce time and cost for developing systems, it can avoid future corrections into systems, as well. 2) M&S can be used for conception, training, maintenance, etc., requiring less expensive tools and previously preparing people to the real scenario. 3) When it comes to situations that involve aerospace or other products, where high costs are involved, mistakes can be avoided or at least minimized. Summarizing, M&S can reduce project cost and schedule, and improve quality.
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