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Loping, defined here as skipping without a foot exchange, is a gait uncommonly used by humans on Earth, but favored by Apollo astronauts during lunar surface excursions. Astronauts may have adopted loping due to space suit-imposed mobility restrictions or because of a possible stability advantage conferred by a relatively constant and wide support base. To evaluate whether loping confers metabolic advantages we monitored ten subjects during loping and running, simulating reduced gravity via partial body suspension, and simulating suited conditions using a lower body exoskeleton. In lunar gravity, loping incurred lower metabolic costs than running for every subject; loping, while efficient at low gravity levels, was less efficient than running in Earth gravity.

The On-line Project Information System (OPIS) is a web-based database developed at NASA Ames Research Center (ARC) to improve information transfer and data availability for Exploration Life Support (ELS) projects. The tool enables users to investigate NASA technology development efforts, connect with knowledgeable experts, and to communicate important information. Within OPIS, Principal Investigators (PI's) post technical, administrative, and project participant information for other users to access through browse and search mechanisms. PI's are given technical data reporting requirements in the form of annual report templates, to assure that the information reported satisfies the most critical data needs of various ELS user groups. OPIS fulfills data and functionality needs of key user groups in the ELS Community through data solicitation, centralization, and distribution. The tool also circumvents data loss with ELS participant turnover.

This paper describes work that has begun at Ames Research Center on development of a heat melt compactor that can be used on near term and future missions. The heat melt compactor can handle wastes with a significant plastic composition and minimize crew interaction. The current solid waste management system employed on the International Space Station (ISS) consists of compaction, storage, and disposal. Wastes such as plastic food packaging and trash are compacted manually and wrapped in duct taped “footballs” by the astronauts. Much of the waste is simply loaded into the empty Russian Progress spacecraft that is used to bring supplies to ISS. The progress spacecraft and its contents are intentionally burned up in the earth's atmosphere during reentry. This manual method of trash management on ISS is a wasteful use of crew time and does not transition well to far term missions.

The current CO2 removal technology of NASA is very energy intensive and contains many non-optimized subsystems. This paper discusses the concept of a next-generation, membrane-integrated, adsorption processor for CO2 removal and compression in closed-loop air revitalization systems. The membrane module removes water from the feed, passing it directly into the processor's exhaust stream; it replaces the desiccant beds in the current four-bed molecular sieve system, which must be thermally regenerated. Moreover, in the new processor, CO2 is removed and compressed in a single two-stage unit. This processor will use much less power than NASA's current CO2 removal technology and will be capable of maintaining a lower CO2 concentration in the cabin than that can be achieved by the existing CO2 removal systems.

A generalized computer program for analysis of pressure and composition in multiple volume systems has been under development by the National Aeronautics and Space Administration (NASA) since 1976. This paper describes the most recent developments in the program. These improvements include the expansion of the program to nine volumes, improvements to the model of the International Space Station (ISS) carbon dioxide removal system, and addition of a detailed Sabatier carbon dioxide reduction mode. An evaluation of the feasibility of adding of trace contaminant tracking was also performed. This paper will also present the results of an analysis that compares model predictions with ISS flight data for carbon dioxide (CO2) maintenance.

In an effort to define and advance the new discipline of Space Architecture, the AIAA technical subcommittee on Aerospace Architecture organized a Space Architecture Workshop that took place during the World Space Congress 2002 in Houston, Texas. One of the results of this workshop is a “Mission Statement for Space Architecture” that addresses the following core issues in a concise manner: definition, motivation, utility, required knowledge, and related disciplines. The workshop also addressed the typology and principles of space architecture, as well as basic philosophical guidelines for practitioners of this discipline. The mission statement, which was unanimously adopted by the workshop participants, reads as follows ([1], [2], [3]): “Space Architecture is the theory and practice of designing and building inhabited environments in outer space, responding to the deep human drive to explore and occupy new places.

This paper reports on the Thermal Control System (TCS) of the AMS-02 (Alpha Magnetic Spectrometer). AMS-02 will be installed on the International Space Station (ISS) Starboard segment of the Truss in 2005, where it will acquire data for at least three years. The AMS-02 payload has a mass of about 6700 kg, a power budget of 2kW and consists of 5 different instruments, with their associated electronic equipment. Analytical integration of the AMS-02 thermal mathematical model is described in the paper, together with the main thermal design features. Stringent temperature stability requirements have been satisfied, providing a stable thermal environment that allows for easier calibration of the detectors. The overall thermal design uses a combination of standard and innovative concepts to fit specific instruments needs.

Environmental Control and Life Support (ECLS) functionality aboard the International Space Station (ISS) includes responses to emergency conditions. The ISS requirements define three types of emergencies: fire, rapid depressurization, and hazardous or toxic atmosphere. The ISS has automatic integrated vehicle responses to each of these emergencies. These automated responses are designed to aid the crew in their response actions during the emergencies. This paper focuses on the ISS response to fire emergencies. It includes the integrated ISS automatic vehicle response and crew actions for fire. Philosophies covered include fire detection, fire response, and post-fire atmosphere recovery. Current responses and crew actions are discussed for the existing vehicle configuration on-orbit. This includes modules in the assembly sequence up to and including the Docking Compartment (DC1). Possible future improvements to the fire emergency responses are also described.

A closed-loop air revitalization system requires continuous removal of CO2 from the breathing air and an oxygen recovery system to recover oxygen from the waste CO2. Production of oxygen from CO2 is typically achieved by reacting CO2 with hydrogen in a reduction unit such as a Sabatier reactor. The air revitalization system of International Space Station (ISS) currently operates on an open loop mode where CO2 is being vented into the space vacuum due to lack of a Sabatier Reactor. A compressor and a storage device are required to interface the Carbon Dioxide Removal Assembly (CDRA) and the Sabatier reactor. This compressor must acquire the low-pressure CO2 from CDRA and provide it at a high enough pressure to the Sabatier reactor. The compressor should ensure independent operations of CDRA and Sabatier reactor at all times, even when their operating schedules are not synchronized.

The Advanced Life Support Research and Technology Development Metric, or Metric, for Government Fiscal Year 2002 provides a measure of the equivalent system mass for a life support system using the “best” available advanced technologies compared to the equivalent system mass for a life support system using technologies from International Space Station. The present paper details the assumed life support system configurations and algorithm used to compute the Metric. Additionally, various peripheral issues of importance are mentioned.

Of the many competing technologies for resource recovery from solid wastes for long duration manned missions such as a lunar or Mars base, incineration technology is one of the most promising and certainly the most well developed in a terrestrial sense. Various factors are involved in the design of an optimum fluidized bed incinerator for inedible biomass. The factors include variability of moisture in the biomass, the ash content, and the amount of fuel nitrogen in the biomass. The crop mixture in the waste will vary; consequently the nature of the waste, the nitrogen content, and the biomass heating values will vary as well. Variation in feed will result in variation in the amount of contaminants such as nitrogen oxides that are produced in the combustion part of the incinerator. The incinerator must be robust enough to handle this variability. Research at NASA Ames Research Center using the fluidized bed incinerator has yielded valuable data on system parameters and variables.

Engineers at the Johnson Space Center (JSC) are using innovative strategies to design the TCS for the Bio-regenerative Planetary Life Support Systems Test Complex (BIO-Plex), a regenerative advanced life support system ground test bed. This paper provides a current description of the BIO-Plex TCS design, testing objectives, analyses, descriptions of the TCS test articles expected to be tested in the BIO-Plex, and forward work regarding TCS. The TCS has been divided into some subsystems identified as permanent “infrastructure” for the BIO-Plex and others that are “test articles” that may change from one test to the next. The infrastructure subsystems are the Heating, Ventilation and Air-Conditioning (HVAC), the Crew Chambers Internal Thermal Control Subsystem (CC ITCS), the Biomass Production Chamber Internal Thermal Control Subsystem (BPC ITCS), the Waste Heat Distribution Subsystem (WHDS) and the External Thermal Control Subsystem (ETCS).

The Biomass Production Chamber (BPC) Sizing Model has been designed to incorporate plant growth chamber options into NASA’s Advanced Life Support Sizing Analysis Tool. The concept addressed by the model is that the gas exchange from a biomass production chamber, in conjunction with human metabolic data and food consumption rates, can be used to estimate the chamber size necessary for the gas exchange and food production rate required for a specific crew size. NASA’s baseline design utilizes a 78m2 (840 ft2) plant growth area and a 9.45m (31 ft) center shelf length. Using an iterative comparison method, the center shelf is incremented by 1.5m (5 ft) sections until necessary food production requirements and gas exchange rates are satisfied.

A SINDA/FLUINT model was developed for performing the thermal analysis of the compressible gaseous nitrogen (GN2) flow of X-38 pressure control system (PCS). The purpose of this analysis is to predict the thermal performance of X-38 PCS for the first mission phase, and to ensure that the GN2 pressure in tank stays above 1000 psi and the GN2 temperature in tank stays above −65°F during a real mission phase. The model simulations of the X-38 PCS have been conducted with the flowrates of the first mission phase for different ambient and GN2 temperatures with/without heating the GN2 tank wall. The predicted results show that the GN2 pressures and temperatures fulfill the requirements and limitations of the X-38 pressure control system without heating the GN2 tank wall. The electrical heaters on the GN2 tank exterior may be eliminated.

A key component of an Advanced Life Support (ALS) system is the solid waste handling system. One of the most important data sets for determining what solid waste handling technologies are needed is a solid waste model. A preliminary solid waste model based on a six-person crew was developed prior to the 2000 Solid Waste Processing and Resource Recovery (SWPRR) workshop. After the workshop, comments from the ALS community helped refine the model. Refinements included better estimates of both inedible plant biomass and packaging materials. Estimates for Extravehicular Mobility Unit (EMU) waste, water processor brine solution, as well as the water contents for various solid wastes were included in the model refinement efforts. The wastes were re-categorized and the dry wastes were separated from wet wastes. This paper details the revised model as of the end of 2001. The packaging materials, as well as the biomass wastes, vary significantly between different proposed Mars missions.

To effectively develop advanced life support technologies to support humans on future missions into space, the requirements for these missions must first be defined. How many people will go? Where will they go? What risks must be protected against? Since NASA does not officially establish new exploration programs until authorized by Congress, there are no program requirements documents or list of “planned missions” to refer to. Therefore, technology developers must look elsewhere for information on how and where their development efforts and concepts may be used. This paper summarizes the development of several sources designed to help Advanced Life Support researchers working to extend a human presence in space.

In July 2001, during Space Shuttle Flight 7A, the Joint Airlock was added to the International Space Station (ISS) and utilized in performing the first extravehicular activity (EVA) from the ISS. Unlike previous airlock designs built by the United States or Russia, the Joint Airlock provides the ISS with the unique capability for performing EVAs utilizing either U.S. or Russian spacesuits. This EVA capability is made possible by the use of U.S.- and Russian- manufactured hardware items referred to as Servicing and Performance Checkout Equipment (SPCE) located in both the Joint Airlock's Equipment and Crew Locks. This paper provides a description for each SPCE item along with a summary of the requirements and capabilities provided in support of EVA events from the ISS Joint Airlock.

This paper provides an overview of the IMMWPS Integrated Ground Test Program, completed at the NASA Johnson Space Center (JSC) during October and November 2001. The JSC Crew and Thermal Systems Division (CTSD) has developed the IMMWPS orbital flight experiment to test the feasibility of a microbe-based water purifier for use in zero-gravity conditions. The IMMWPS design utilizes a Microbial Processor Assembly (MPA) inoculated with facultative anaerobes to convert organic contaminants in wastewater to carbon dioxide and biomass. The primary purpose of the ground test program was to verify functional operations and procedures. A secondary objective was to provide initial ground data for later comparison to on-orbit performance. This paper provides a description of the overall test program, including the test article hardware and the test sequence performed to simulate the anticipated space flight test program. In addition, a summary of significant results from the testing is provided.

There have been many software programs that have provided simulations for the performance and operation of the Environmental Control and Life Support Subsystems (ECLSS) in the International Space Station (ISS) and in the Space Shuttle. These programs have been applied for purposes in system analysis, flight analysis, and ECLSS studies. Flight and system analysis tasks are deemed important. Therefore, more manpower and resources added for such work is considered beneficial. System analysis covers design and trouble-shooting, the validation of Flight Rules, and the contingency analysis. During the engineering design phase, ECLSS modelers predict the performance and interaction of units in a process train. Simulation results can be useful in estimating equipment sizes and costs. This article has also used two examples to illustrate that many Flight Rules need to be validated using properly selected integrated programs.

A thermal analysis of the compressible carbon dioxide (CO2) flow for the Portable Fire Extinguisher (PFE) system has been performed. A SINDA/FLUINT model has been developed for this analysis. The model includes the PFE tank and the Temporary Sleep Station (TeSS) nozzle, and both have an initial temperature of 72 °F. In order to investigate the thermal effect on the nozzle due to discharging CO2, the PFE TeSS nozzle pipe has been divided into three segments. This model also includes heat transfer predictions for PFE tank inner and outer wall surfaces. The simulation results show that the CO2 discharge rates and component wall temperatures fall within the requirements for the PFE system. The simulation results also indicate that after 50 seconds, the remaining CO2 in the tank may be near the triple point (gas, liquid and solid) state and, therefore, restricts the flow.