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As space flights tend to be more prolonged problems of oxygen generation by physicochemical means assume greater importance. The paper deals with the water, electrolysis process, CO2 concentration and processing organisation schemes. Some operational results of the system for electrolysis of aqueous alkali solution and CO2 removal on Mir space station are presented. Expected characteristics of the complex system for oxygen generation from carbon dioxide are considered.

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.

This paper describes a computational technique for prediction of the flow and thermal environment in the Space Shuttle Solid Rocket Motor field joint cavities. The SRM field joint hardware has been tested with a defect in the insulation. Due to this defect, the O-ring gland cavities are pressurized during the early part of the ignition. A computer model has been developed to predict the flow and thermal environment through the simulated flaw, during the pressurization of the field joint. The transient mass, momentum, and energy conservation equations in the flow passage in conjunction with the thermodynamic equation of state are solved by a fully implicit iterative numerical procedure. Since this is a conjugate flow and heat transfer problem, wall temperatures are calculated by solving the one-dimensional transient heat conduction equation in the solid along with the other governing equations. The pressure and temperature predictions have been compared with the test data.

A concept of developing a regenerative water management system (RWMS) for first lunar base missions is reviewed. The principal feature of the concept proposed is the maximum possible unification of RWMS for long-duration orbiting station and a lunar base with due regard to possible modification of the hardware for lunar gravity conditions. The paper is based on the expertise in research, development, testing and flight operation of RWMS in Russia. An upgraded RWMS of the International Space Station may be used for first lunar missions.

This paper describes a life support and EVA system for an SSTO that will have minimum mass impact on spaceship design while permitting full in-flight functionality, ready EVA, adequate back-up in emergencies and simplified maintenance and checkout. The system premises a single crewmember, continuously suited operations, limited on-orbit stay, an unpressurized cabin and EVA without need for an airlock. Conceptual drawing and mass estimate are provided.

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.

Ames Research Center’s Life Sciences Division has developed and flown an extensive array of spaceflight experiment unique equipment (EUE) during the last decade of the twentieth century. Over this ten year span, the EUE developed at ARC supported a vital gravitational biology flight research program executed on several different platforms, including the Space Shuttle, Spacelab, and Space Station Mir. This paper highlights some of the key EUE elements developed at ARC and flown during the period 1990-1999. Resulting lessons learned will be presented that can be applied to the development of similar equipment for the International Space Station.

The International Space Station Alpha (ISSA) conceptual design has several notable differences from previous Space Station design efforts. One key difference centers around the Intermodule Ventilation (IMV). While previous IMV designs incorporated standalone ducts at each element-to-element interface, the present approach includes several IMV ducts which are configured into the central Temperature and Humidity Control (THC) ducting networks. A simplified analytic technique is presented, which assesses compliance of the overall IMV approach to the established requirement which limits IMV short circuiting to a maximum of 40% at a fan flow rate of 140 cfm. Test results (from the Space Station Freedom IMV Test) and theoretical performance results are input to the analytic technique.

Successful trace chemical contamination control is one of the components necessary for achieving good cabin atmospheric quality. While employing seemingly simple process technologies, sizing the active contamination control equipment must employ a reliable design basis for the trace chemical load in the cabin atmosphere. A simplified design basis that draws on experience gained from the International Space Station program is presented. The trace chemical contamination control design load refines generation source magnitudes and includes key chemical functional groups representing both engineering and toxicology challenges.

Astronaut cooling during extravehicular activity is a critical design issue in developing a portable life support system that meets the requirements of a space station mission. Some of the requirements are that the cooling device be easily regenerable and nonventing during operation. In response to this, a direct-interface, fusible heat sink prototype with freezable quick-disconnects has been developed. A proof-of-concept prototype has been constructed and tested that consists of an elastic container filled with normal tap water and having two quick-disconnects embedded in a wall. These quick-disconnects are designed so that they may be frozen with the ice and yet still be joined to the cooling system, allowing an immediate flow path. The inherent difficulties in a direct-interface heat sink have been overcome, i.e., (1) establishing an initial flow path, (2) avoiding low-flow freeze-up, and (3) achieving adequate heat-transfer rates at the end of the melting process.

This paper describes a dishwasher ground test unit which has been designed to wash eating utensils in the microgravity environment of the Space Station. The basic wash process is described as well as the methods used for controlling the wash and rinse water. The required interfaces to the Space Station are discussed and the amount of resources consumed during a complete wash cycle are presented. The paper is concluded with a discussion of several growth versions of the dishwasher which will accommodate increases in the number of crew persons on board the Space Station.

This paper features a distributed environment and the steps taken to incorporate the Virtual Range model into the Virtual Test Bed (VTB) infrastructure. The VTB is a prototype of a virtual engineering environment to study operations of current and future space vehicles, spaceports, and ranges. The High-Level Architecture (HLA) is the main environment. The VTB/HLA implementation described here represents different systems that interact in the simulation of a Space Shuttle liftoff. An example implementation displays the collaboration of a simplified version of the Space Shuttle Simulation Model and a simulation of the Launch Scrub Evaluation Model.

This is followed by an outline of a fire safety analysis of the spacecraft including an outline of a probabilistic risk analysis (PRA). The particular emphasis of this analysis is the change in risk as the vehicle moves to lower pressure, higher operating voltage and increased oxygen mole fraction.

The effects on humans and spacecraft systems are also discussed in detail.

The paper gives an update on an advanced development effort carried out under NASA Johnson Space Center (NASA/JSC) NAS 9-17775 by Ergenics Power Systems, Inc. (EPSI). The work was initiated in April 1987 to design and build a Fuel Cell Energy Storage System (FCESS) bench-test unit for the Space Station Freedom Extravehicular Mobility Unit (EMU). Fueled by oxygen and hydride stored hydrogen, the FCESS is being considered as an alternative to the EMU zinc-silver oxide battery. Superior cycle life and quick recharge are its main attributes. Design and performance of a non-venting 28V, 34 Ahr system with 7 amp rating are discussed. The FCESS is comprised of a 32-cell proton exchange membrane (PEM) stack, a metal hydride storage vessel and a control subsystem. The stack design incorporates passive product-water removal and thermal integration with the hydride vessel. The hydride vessel stores enough fuel for 5 hours.

A greater number of manned extravehicular activities (EVAs) are anticipated for the United States Space Station compared to the few experienced on Space Shuttle missions. This requires the design of a new generation extravehicular mobility unit (EMU). Limitations inherent in the current EMU power supply--zinc silver-oxide batteries--include dry shelf-life, active wet-life, cycle-life, and recharge time, thus making its usage impractical for the Space Station. An alternative solution, a fuel cell energy storage system (FCESS), is being explored by Ergenics Power Systems, Inc. (EPSI), Wyckoff, N.J., with funding from NASA/Johnson Space Center. The ion-exchange membrane (IEM) fuel cell under consideration utilizes hydrogen stored as a metal hydride. EPSI has demonstrated experimentally that the fuel cell/hydride technology pair should be a primary candidate EMU power supply for its high volumetric/energy density and cycle life, quick recharge, durability, EMU integration, and safety.

The man-made ecosystem of any spacecraft is distinguished from the natural ecosystem as follows: (a) Man is the decisive part of the system defining the main requirements to its properties, functions and developing laws; (b) the processes of controlled substance turnover are accomplished in the limited number of technical units at rates substantially exceeding those of slow natural processes.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: (a) Functional considerations. (b) Weight considerations. (c) Environmental performance factors. (d) End fitting types. (e) Additional considerations.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: (a) Functional considerations. (b) Weight considerations. (c) Environmental performance factors. (d) End fitting types. (e) Additional considerations.

The factors involved in the selection of a quick-disconnect are grouped into the following classifications for the purpose of discussion: (a) Functional considerations. (b) Weight considerations. (c) Environmental performance factors. (d) End fitting types. (e) Additional considerations.