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The ORZS flight experiment is designed to measure gas diffusion through plant growth substrates at varying water content levels in microgravity. This information is critical for proper water management and the prevention of root zone hypoxia during plant growth and advanced life support (ALS) biomass production experiments. Microgravity data that suggest enhanced hysteresis in water retention may alter the gas diffusion process, changing the optimum root zone moisture control set point in μg plant growth systems. Small gas diffusion cells are being evaluated as measurement systems for coarse-textured plant growth media at 1g and 0g. Design guidelines aim to minimize gravitational force while maintaining a representative porous medium. Substrate physical properties (e.g., water retention) pose additional complications for diffusion coefficient determination.

It’s a common practice to use different kinds tools to aid in the development and verification of modern safety critical avionics systems. These tools play a key role in avionics engineering and used in all project phases: requirements development, software design, source code development, integration, configuration management, and verification. Tools assist to analyze and improve system safety by automation of some of the activities which if performed manually and are therefore prone to human error. However, incorrect functioning of a tool can have negative impact on the safety and performance of the Safety Critical system. Hence, tools are proposed to be qualified whenever any of the design assurance process(es) described in RTCA/DO-178C or RTCA/DO-254 are eliminated, reduced, or automated using the tool unless the output of the tool is verified manually. Qualification of the tool gives confidence in the tool functionality.

An inventory was made of the quantities and types of wastes to be produced by typical missions proposed by NASA's Office of Space Science and Applications (OSSA) for the initial operational phase (IOC) of the Space Station. Of the 35 missions inventoried, 21 missions involve “payloads” (instrument packages) attached externally to the Space Station, 12 involve payloads that are located on “free-flying” platforms remote from the Station and 2 missions, (Life Sciences and Materials Sciences laboratories) comprise a complex series of experiments to be carried out inside the Station's pressurized volume. The study objective was to acquire the information needed to define preliminary OSSA waste management requirements for the Space Station and the National Space Transportation System. The study revealed that all missions combined will generate approximately 5350 kg (11800 lbs) of waste (solid, liquid and gas) every 90 days.

OV-10A LANDING GEARS - The landing gears of the OV-10A have been designed to meet extremely severe landing and operating conditions. The articulated main gear and semi-articulated nose gear assemblies have proven to be well suited to meeting the requirements for high sink rate landings onto bumps, steps and holes in addition to taxiing and making take-offs over undulating contours. Development data on the landing gear shock struts in laboratory airframe drops and actual flight test landings show good agreement with predicted performance.

Life Cycle Cost (LCC) analysis forms a vital input to the design of cost effective aerospace propulsion systems. By necessity, LCC analysis requires extensive communication between a large range of participants in a given program: customer, aircraft manufacturer, engine producer, equipment suppliers, and across professional disciplines within each of these organisations. This paper presents an overview of ARP 4294, “Data Formats and Practices for Life Cycle Cost Information”, which provides a range of specific data formats and recommended practices to support these communications. ARP4294 is primarily directed at the LCC of military propulsion systems. Consistency and understanding of information exchanged are promoted as are the role and responsibilities of participants at each phase of the program. ARP 4294 supplements the general guidelines of AIR 1939 and complements ARP 4293.

This paper summarizes results from the first NASA Life Support Systems Analysis Workshop sponsored by the Office of Aeronautics and Space Technology on June 24-27, 1991, in Milwaukee, Wisconsin, and provides a brief overview of the second workshop held May 12-14, 1992. The objectives of the workshops were to: 1) encourage communication in life support systems analysis among NASA, the aerospace industry, universities, and the chemical processing industry; 2) provide access and exposure to current NASA life support systems analysis efforts; 3) establish and provide results of the workshop sessions to NASA and the participants regarding future activities and directions for the development of life support systems analysis capabilities. The participants included representatives from NASA Headquarters and field centers, major aerospace companies, aerospace R&D and manufacturing companies, chemical processing companies, and universities.

LIQUID-OXYGEN injection, especially in combination with water injection, has proved to be a practicable means of improving power output of aircraft engines at altitude. Its use for limited periods in nonservice installations has increased speed, rate of climb, and operational ceiling without increasing the tendency toward knocking. The injection system can be readily applied to existing aircraft. It is remarkably light in weight - a system weighing 180 lb, including about 100 lb of oxygen, will increase the power of an R-2800 by 300 hp for 16 min. Maximum permissible boost is limited by engine cooling.

A reference architecture model of a typical fire control system has been established with the Real-time Object-Oriented Modeling (ROOM) environment, ObjecTime. An external graphics user interface (GUI) has also been developed to communicate with the reference architecture, thus making the reference architecture an ideal tool to test a specific design based on the architecture implementation. The GUI also communicates with an independent ballistics calculation program to send the target parameters and receive the ballistics calculation results. The ObjecTime model, the GUI, and the external ballistics calculation program constitute a demonstration system for the fire control reference architecture.

This paper describes a high frame rate focal-plane-array range camera module, based on optical time-of-flight measurement, along with machine vision algorithms that take advantage of the real-time 3D information. The utility of such technology is demonstrated in an advanced backup safety system. This system detects obstacles lying on the ground as well as tracks moving objects. Using dual detection criteria, the system outperforms existing backup proximity sensors. Based on 3D imagery collected from a rear-viewing camera configuration, we evaluate the detection and tracking accuracy for varying object sizes and ranges. Operational experience shows that our time-of-flight range camera can be a cost-effective and reliable component of intelligent automotive safety and driver assist systems.

This work reports a conception phase of a piston engine global model. The model objective is forecast the motor performance (power, torque and specific consumption as a function of rotation and environmental conditions). Global model or Zero-dimensional is based on flux balance through each engine component. The resulting differential equations represents a compressive unsteady flow, in which, all dimensional variables are areas or volumes. A review is presented first. The ordinary differential equation system is presented and a Runge-Kutta method is proposed to solve it numerically. The model includes the momentum conservation equation to link the gas dynamics with the engine moving parts rigid body mechanics. As an oriented to objects model the documentation follows the UML standard. A discussion about the class diagrams is presented, relating the classes with physical model related. The OOP approach allows evolution from simple models to most complex ones without total code rewrite.

This paper describes the NASA/JSC Research Technology Opportunity Program (RTOP) activity to assess the supportability of space systems throughout their life cycles. Supportability analyses for space systems present unique attributes and problems. The OSMOSSYS (Object oriented Simulation of Maintenance and Operations for Space Systems) was developed using object-oriented design concepts to provide NASA an analysis tool which addresses the question “Will a proposed space facility be able to successfully perform the missions for which it is designed?” This model integrates the complete configuration of the system including the reliability and maintainability characteristics of each component, the logistics support, and the mission operations of the facility to assess the success rate of the planned mission(s). Two parallel design processes are being utilized; developing core modules utilizing C + +, and incorporating as much code and ideas as possible from existing NASA models.

As ALS goals branch out to extended missions to the moon and Mars, concurrent science and engineering projects take center stage in the development of new ALS technology. It is necessary to optimize the interdisciplinary research activities in order to ensure ALS research goals are met in a timely manner, and to guarantee the reliability of future long term missions. The SSM team of the NJ-NSCORT has developed an internet software platform capable of performing a systems level analysis of the ALS research activity. The information produced by the analysis can assist ALS researchers in the streamlining of research activity.

In the last decade, significant aerodynamic and manufacturing progress has been made in the area of achieving natural laminar flow over practical swept and unswept lifting surfaces. Further significant reduction in total aircraft drag is predicted by achieving significant amounts of additional natural laminar flow also over fuselages and other nonlifting airframe components. To date, only limited experimental results are available that examine the applicability of laminar flow over nonaxisymmetric fuselage shapes. The paper presents details of a cooperative NASA/Cessna flight experiment using a light twin-engine propeller-driven aircraft, to investigate transition location and transition mode over the nonaxisymmetric fuselage forebody. A discussion is given of the transition-instrumentation layout and the planned flight-test matrix.