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Of the possible Life Support Systems evaluation criteria, the criterion of "integral reliability" is proposed. This criterion incorporates three main indices: reliability, mass, and quality of life. It is possible to interrelate these indices only if the space mission is considered as a whole. It is shown that there must exist a LSS mass optimum with respect to mission reliability. The specific form of "integral reliability" expression and the number of terms depend on the mission scenario. This work considers different LSS for orbital station, Lunar base, and Mars mission scenarios.

The NASA Office of Exploration (OXEP) was established in June 1987 to provide recommendations and viable alternatives for an early 1990's national decision on a focused program for human exploration of the solar system, particularly of the Moon and Mars. 1 Missions beyond the low earth orbit Space Station Freedom poise new and different challenges for crew life support systems (LSS). Case study missions under consideration will demand careful selection of reliable and efficient LSS technology by the mission planners. This paper describes a study currently underway to develop a Mission Planners LSS Guidebook for providing tabular data, such as weight, volume, and power for comparing various LSS approaches against key drivers derived from mission case studies. These quanitative data facilitate LSS approach selection for any mission of interest bounded by the current OXEP case studies.

Evaluation of Life Support System (LSS) mass has to take into account not only mass of components and stock of expendable substances but also the mass of power supply and heat rejection systems. The productivity of biological regeneration processes grows with power supply but at high level of power supply the efficiency of these processes is decreased. On the other hand increasing of power supply causes growing of energetic and hit rejection system mass. So, optimization problem on optimal intensity of regeneration processes appears. It is shown that the value of power supplied providing minimal total mass of LSS does not depend on the level of closure and mission duration.

Exploration Life Support (ELS) is a technology development project under the National Aeronautics and Space Administration's (NASA) Exploration Technology Development Program. The ELS Project's goal is to develop and mature a suite of Environmental Control and Life Support System (ECLSS) technologies for potential use on human spacecraft under development in support of U.S. Space Exploration Policy. Technology development is directed at three major vehicle projects within NASA's Constellation Program: the Orion Crew Exploration Vehicle (CEV), the Altair Lunar Lander and Lunar Surface Systems, including habitats and pressurized rovers. The ELS Project includes four technical elements: Atmosphere Revitalization Systems, Water Recovery Systems, Waste Management Systems and Habitation Engineering, and two cross cutting elements, Systems Integration, Modeling and Analysis, and Validation and Testing.

In a long term vision of space exploration an orbiting station located at Earth Moon Lagrangian Point 1 (EML1), named ECLIPSE should act as a logistic node supporting traffic between Earth, Moon and the future manned and unmanned missions towards Mars. The paper presents the results of the study performed during the SEEDS III Project Work Phase: focusing on the preliminary concepts of the Habitability and the Environmental Control and Life Support System for the ECLIPSE Medical Center (EMC) and ECLIPSE Quarantine Module (EQM), the Cis Lunar Orbiting Shuttle (CLOS) and the Mobile Pressurized Control Module (MPCM).

This paper presents the requirements and baseline design for a subsurface Life Support System (LSS) to support an underground habitat. The purpose of this effort was to demonstrate/validate the feasibility of building an operational habitat to support survivable and enduring operations of a deeply based ICBM weapon system. Described is an overall life support design for a crew of 100 to 600 persons that encompasses all required life support subsystems, arrangement and construction of Habitat enclosures and protection from the effects of a subsurface environment. Effects of habitat layout, type of power source, environment, rock temperature and moisture content, crew size and mission length were investigated. Regenerative and non-regenerative systems were compared on the basis of life cycle cost. Results of this Life Support System study were much different than those previously conducted for space and submarine application due to the difficulty in rejecting heat.

NASA's Office of Exploration depends on both robotic and human exploration system capabilities to support a rich set of lunar and Mars mission options. Permanent operations on the lunar surface will demand high systems availability and low logistics. Mars human exploration missions require sustainable operations with no logistics except what has been forward deployed on earlier missions. This paper will discuss the top-level mission requirements and the systems engineering issues for life support systems which must be addressed to support viable human exploration missions for lunar and Mars applications.

Engineers designing life support systems for NASA's next Lunar Landers face unique challenges. As with any vehicle that enables human spaceflight, the needs of the crew drive most of the lander requirements. The lander is also a key element of the architecture NASA will implement in the Constellation program. Many requirements, constraints, or optimization goals will be driven by interfaces with other projects, like the Crew Exploration Vehicle, the Lunar Surface Systems, and the Extravehicular Activity project. Other challenges in the life support system will be driven by the unique location of the vehicle in the environments encountered throughout the mission. This paper examines several topics that may be major design drivers for the lunar lander life support system. There are several functional requirements for the lander that may be different from previous vehicles or programs and recent experience.

Applied research and technology development (R&TD) is often characterized by uncertainty, risk, and significant delays before tangible returns are obtained. Given the increased awareness of limitations in resources, effective R&TD today needs a method for up-front assessment of competing technologies to help guide technology investment decisions. Such an assessment approach must account for uncertainties in system performance parameters, mission requirements and architectures, and internal and external events influencing a development program. The methodology known as decision analysis has the potential to address these issues. It was evaluated by performing a case study assessment of alternative carbon dioxide removal technologies for NASA's proposed First Lunar Outpost program. An approach was developed that accounts for the uncertainties in each technology's cost and performance parameters as well as programmatic uncertainties such as mission architecture.

Plants can be grown in space to support human life, providing food, and regenerating water and air. Various groups have demonstrated that plants can support human life on the ground, and that plants can grow in space. One would suppose that plants are also able to support human life in space, though obviously it would be a good idea to demonstrate that ability before committing to a mission requiring bioregeneration. However, plant growth in space requires that we provide the necessary conditions for growth, and this might require not only providing water and fertilizer as we do in terrestrial agriculture, but also a controlled environment and lighting. This would make crops much more costly than we are accustomed to on Earth, where the majority of crops are grown outside and where natural sunlight is generally adequate. On the other hand, providing food, air, and water in space by any other means is also costly.

The paper describes some of the features of a reference manual to be issued by the European Space Agency that will form part of a set of standards covering the subjects of environmental control, life support, habitability and human factors. The Manual contains information on the general requirements of life support and habitability and the missions that will drive its associated technologies. It is formatted as a series of individual data sheets that can be updated regularly and which are designed to accommodate inputs from other organisations and individuals. It also includes details of promising experimental work and theoretical concepts, as well as historical reviews that will help to guide the selection of technologies and the design of new systems. The paper presents examples from the Manual which highlight aspects of a systems approach to life support.

Studies for manned logistic spacecraft have provided much information and preliminary design data. This paper presents the results of an evaluation that led to the selection of environmental control, life support, and auxiliary power subsystems for a winged lifting body spacecraft. The vehicle was designed to be usable for a variety of missions such as space laboratory logistics and resupply, rescue, and reconnaissance-surveillance.

This paper considers the design of safety systems as they might be applied to a manned habitat operating in space. Areas reviewed include the delineation, monitoring and suppression of hazards as well as the design of control systems. Examples of methods that could be used to suppress hazards are presented, including schematics for a shut-down hierarchy and a fire and hazardous gas control system.

In this paper we consider sample size selection for life tests when the product life follows the two parameter Weibull distribution. Two situations are considered: 1) an acceptance test where the purpose is to determine whether the product under test meets specified or historical life objectives and 2) a routine endurance test where the purpose is to determine a parameter’s value within a sufficiently small interval of uncertainty just to add to a growing body of knowledge and serve as an item of information in future as yet unformulated decision making processes.

Given the constraints of the current launchers, manned exploration beyond LEO implies long time missions, a high mass of metabolic consumables and consequently regenerative life support technologies developments. To validate their efficiency, as well as their reliability, these technologies need to be tested in the most analog conditions (i.e. isolation, limited spare part, …). A large number of these conditions are met in the new permanent French-Italian settlement called Concordia, currently being built in the Antarctic continent. Over the last 15 years, ESA developed regenerative life support technologies. Two of these technologies: a Grey Water Treatment Unit and a Black Water Treatment Unit are currently assembled at the size of 15 to 70 persons to fulfill the Concordia crew needs The first technology is a multi step filtration system and will recycle the shower, washing machine, dish washer and cleaning water.

The lead-acid couple is potentially capable of fulfilling the battery requirement for high performance electric delivery vehicles in the one tonne payload category. Development of such a battery, combining high energy density and good cycle life, involves extensive and painstaking testing. During the course of the Lucas development programme test methods and procedures have been evolved to ensure that the battery array with its supporting equipment is capable of fully performing the tasks required of it in such an application. Much of the experience gained is applicable to any electrochemical couple being developed for electric vehicle use.

This paper presents life test data of two controlled pump assemblies continuously running since September 1993. The tests, running on FLUOROCARBON CCIF2 - CCIF2, are still in progress (Current date May 1997). One pump operates at the design point, the other one at 3 different RPM's. Reliability considerations lead to a novel, sensorless, brushless DC motor of very high reliability. Given is an outline of the extensive environmental test compaign and Micro-G tests, with results. Pump performance data taken prior and after the environmental tests, performances after 1 and 3 years of continuous operation are given and compared. Up to now, after 3 years of operation no pump degradation can be detected. A pre-runner of the above pumps, featuring the same bearing design is continuously running since November 1990 with no observable degradation.

One of the key selling criteria of brake linings is their related cost per life time. Individual wear rates must match a required service interval which in most cases is part of the warranty a vehicle is sold with. OEMs, brake manufacturers as well as friction material suppliers are therefore conducting in-depth investigations on the wear behaviour of brake systems and their friction pair. These consider various parameters influencing pad and rotor life expectancy as part of the pre selection process before running final fleet trials for confirmation. Thus, selecting the right test procedures and parameters for the determination of wear rates is key in enabling a confident life time prediction. As of today, a multitude of wear test procedures are used in the automotive industry, each of them related to the specific experience of the respective OEM or BM.

The knowledge of mechanical behaviour of material is vital for durability prediction and attending initial project requirements. Through the experimental evaluations is possible to measure this behaviour and use it as input in numerical simulations. Temperature changes considerably static and dynamic mechanical properties of materials, particularly in elastomers. This study was motivated to predict the durability under several working temperatures of center bearings rubber cushion of driveshafts that needs to achieve prespecified stiffness and durability parameters. Standardized specimens were tested in fatigue for experimental investigation of the rubber compound. Durability tests were performed in the final product sample and compared with tests performed in standardized specimens. It was concluded that this approach produces accurate results for fatigue predictions and provided useful equations for practical design applications and reducing product validation time.

Theoretical estimates are made of life time of Ceramic Turbocharger Rotor (CTR) for suitable mechanical design and suitable material selection. Life time of CTR is predicted taking into account the stress-temperature distribution in CTR, required failure probability, volume effect of strength and material properties. Three fatigue failure modes which are slow crack growth, oxidation, and creep failure are considered. The stress-temperature distribution in CTR in operation is estimated by means of Finite Element Method numerical analysis. The probabilistic design map is proposed as a function of turbine inlet temperature and tip speed.