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We present a device for collecting and storing feces in microgravity that is user-friendly yet suitable for spacecraft in which cabin volume and mass are constrained. On Apollo missions, the commode function was served using disposable plastic bags, which proved time-consuming and caused odor problems. On Skylab, the space shuttle, and the International Space Station, toilets have used airflow beneath a seat to control odors and collect feces. We propose to incorporate airflow into a system of self-compacting, self-drying collection and stowage bags, providing the benefits of previous commodes while minimizing mass and volume. Each collection bag consists of an inner layer of hydrophobic membrane that is permeable to air but not liquid or solid waste, an outer layer of impermeable plastic, and a collapsible spacer separating the inner and outer layers. Filled bags are connected to space vacuum, compacting and drying their contents.

This paper considers the design of a life support system for transit to Mars and return to Earth. Because of the extremely high cost of launching mass to Mars, the Mars transit life support system must minimize the amount of oxygen, water, and food transported. The three basic ways to provide life support are to directly supply all oxygen and water, or to recycle them using physicochemical equipment, or to produce them incidentally while growing food using crop plants. Comparing the costs of these three approaches shows that physicochemical recycling of oxygen and water is least costly for a Mars transit mission. The long mission duration also requires that the Mars transit life support system have high reliability and maintainability. Mars transit life support cannot make use of planetary resources or gravity. It should be tested in space on the International Space Station (ISS).

In February 2004 NASA released “The Vision for Space Exploration.” The important goals outlined in this document include extending human presence in the solar system culminating in the exploration of Mars. Unprocessed waste poses a biological hazard to crew health and morale. The waste processing methods currently under consideration include incineration, microbial oxidation, pyrolysis and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this project is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. In the Phase I project, TDA Research, Inc. demonstrated the potential of a low temperature oxidation process using ozone. In the current Phase II project, TDA and NASA Ames Research Center are developing a pilot scale low temperature ozone oxidation system.

How much integrated system level test should be performed on a spacecraft before it is launched? Although sometimes system test is minimized, experience shows that systems level testing should be thorough and complete. Reducing subsystem testing is a less dangerous way to save cost, since it risks finding problems later in system test, while cutting systems test risks finding them even later on orbit. Human-rated spacecraft test planning is informal, subjective, and inconsistent, and its extent is often determined by the decision maker's risk tolerance, decision-making style, and long-term or short-term view. Decisions on what to test should be guided by an overall mission cost-benefit analysis, similar to the risk analysis used to guide development efforts.

Experimental measurements of a 1:20-scale tractor-trailer configuration were obtained in the 48- by 32-Inch Subsonic Wind Tunnel at NASA Ames Research Center. The model included significant details of the underbody geometries of both the tractor and trailer. In addition, the tractor included a flow-through grill and a simplified engine block to provide an approximation of the flow through the engine compartment. The experiment was conducted at a Reynolds Number of 430,000 for yaw angles between ±14 deg. The measurements included forces and moments and static surface pressures for various underbody configurations. Simple fairings on the underbodies of the tractor and trailer both yielded a reduction in the wind-averaged drag coefficient of 0.018 (2.7%) when tested separately. A horizontal plate designed to block vertical flow in the tractor-trailer gap provided marginally higher drag reduction (0.021, or 3.2%).

NASA is currently developing two new human rated launch systems. They are the Crew Exploration Vehicle (CEV) and the Lunar Surface Access Module (LSAM). Both of these spacecraft will require new life support systems to support the crew. These life support systems can also be designed to reduce the mass required to keep humans alive in space. Water accounts for about 80% of the mass required to keep a person alive. As a result recycling water offers a high return on investment. Recycling water can also increase mission safety by providing an emergency supply of drinking water. This paper evaluates the potential benefits of two wastewater treatment technologies that have been designed to reduce the mass of the CEV and LSAM missions. For a 3 day CEV mission to the International Space Station (ISS) this approach could reduce the mass required to provide drinking water by 65% when compared to stored water. For an 18 day Lunar mission a mass savings of 70% is possible.

Stored air and water will be sufficient for Crew Exploration Vehicle visits to the International Space Station and for brief missions to the moon, but an air and water recycling system will be needed to reduce cost for a long duration lunar base and for exploration of Mars. The air and water recycling system developed for the International Space Station is substantially adequate but it has not yet been used in operations and it was not designed for the much higher launch costs and reliability requirements of moon and Mars missions. Significant time and development effort, including long duration testing, is needed to provide a flawless air and water recycling system for a long duration lunar base. It would be beneficial to demonstrate air and water recycling as early as the initial lunar surface missions.

CO2 removal, recovery and reduction are essential processes for a closed loop air revitalization system in a crewed spacecraft. Typically, a compressor is required to recover the low pressure CO2 that is being removed from the spacecraft in a swing bed adsorption system. This paper describes integrated tests of a Temperature-Swing Adsorption Compressor (TSAC) with high-fidelity systems for carbon dioxide removal and reduction assemblies (CDRA and Sabatier reactor). It also provides details of the TSAC operation at various CO2 loadings. The TSAC is a solid-state compressor that has the capability to remove CO2 from a low-pressure source, and subsequently store, compress, and deliver it at a higher pressure. TSAC utilizes the principle of temperature-swing adsorption compression and has no rapidly moving parts.

The Vapor Phase Catalytic Ammonia Removal (VPCAR) system is being developed to recycle water for future NASA Exploration Missions. Testing was recently conducted on NASA's C-9B Reduced Gravity Aircraft to determine the microgravity performance of a key component of the VPCAR water recovery system. Six flights were conducted to evaluate the fluid dynamics of the Wiped-Film Rotating Disk (WFRD) distillation component of the VPCAR system in microgravity, focusing on the water delivery method. The experiments utilized a simplified system to study the process of forming a thin film on a disk similar to that in the evaporator section of VPCAR. Fluid issues are present with the current configuration, and the initial alternative configurations were only partial successful in microgravity operation. The underlying causes of these issues are understood, and new alternatives are being designed to rectify the problems.

Pyrolysis processing of solid waste in space will inevitably lead to carbon formation as a primary pyrolysis product. The amount of carbon depends on the composition of the starting materials and the pyrolysis conditions (temperature, heating rate, residence time, pressure). Many paper and plastic materials produce almost no carbon residue upon pyrolysis, while most plant biomass materials or human wastes will yield up to 20-40 weight percent on a dry, as-received basis. In cases where carbon production is significant, it can be stored for later use to produce CO2 for plant growth. Alternatively it can be partly gasified by an oxidizing gas (e.g., CO2, H2O, O2) in order to produce activated carbon. Activated carbons have a unique capability of strongly absorbing a great variety of species, ranging from SO2 and NOx, trace organics, mercury, and other heavy metals.

The 1/8-scale Generic Conventional Model was studied experimentally in two wind tunnels at NASA Ames Research Center. The investigation was conducted at a Mach number of 0.15 over a Reynolds number range from 1 to 6 million. The experimental measurements included total and component forces and moments, surface pressures, and 3-D particle image velocimetry. Two configurations (trailer base flaps and skirts) were compared to a baseline representative of a modern tractor aero package. Details of each configuration provide insight into the complex flow field and the resulting drag reduction was found to be sensitive to Reynolds number.

At 70 miles per hour, overcoming aerodynamic drag represents about 65% of the total energy expenditure for a typical heavy truck vehicle. The goal of this US Department of Energy supported consortium is to establish a clear understanding of the drag producing flow phenomena. This is being accomplished through joint experiments and computations, leading to the intelligent design of drag reducing devices. This paper will describe our objective and approach, provide an overview of our efforts and accomplishments related to drag reduction devices, and offer a brief discussion of our future direction.

NASA is exploring a research activity to identify the technologies that will enable an Extreme Short Take-Off and Landing (ESTOL) aircraft. ESTOL aircraft have the potential to offer a viable solution to airport congestion, delay, capacity, and community noise concerns. This can be achieved by efficiently operating in the underutilized or unused airport ground and airspace infrastructure, while operating simultaneously, but not interfering with, conventional air traffic takeoffs and landings. Concurrently, the Air Force is exploring ESTOL vehicle solutions in the same general performance class as the NASA ESTOL vehicle to meet a number of Advanced Air Mobility missions. The capability goals of both the military and civil vehicles suggests synergistic technology development benefits. This paper presents a summary of the activities being supported by the NASA ESTOL Vehicle Sector.

The Columbia Accident Investigation Board issued a major recommendation to NASA. Prior to return to flight, NASA should develop and implement a comprehensive inspection plan to determine the structural integrity of all Reinforced Carbon-Carbon (RCC) system components. This inspection plan should take advantage of advanced non-destructive inspection technology. This paper describes a non-intrusive technology with a micro-flying robot to continuously monitor inside a space vehicle for any stress related fissures, cracks and foreign material embedded in walls, tubes etc.

This paper describes the initial results of applying two machine-learning-based unsupervised anomaly detection algorithms, Orca and GritBot, to data from two rocket propulsion testbeds. The first testbed uses historical data from the Space Shuttle Main Engine. The second testbed uses data from an experimental rocket engine test stand located at NASA Stennis Space Center. The paper describes four candidate anomalies detected by the two algorithms.

This paper considers system design and technology selection for the crew air and water recycling systems to be used in long duration human space exploration. The ultimate objective is to identify the air and water technologies likely to be used for the vision for space exploration and to suggest alternate technologies that should be developed. The approach is to conduct a preliminary systems engineering analysis, beginning with the Air and Water System (AWS) requirements and the system mass balance, and then to define the functional architecture, review the current International Space Station (ISS) technologies, and suggest alternate technologies.

Pyrolysis is a very versatile waste processing technology which can be tailored to produce a variety of solid liquid and/or gaseous products. The main disadvantages of pyrolysis processing are: (1) the product stream is more complex than for many of the alternative treatments; (2) the product gases cannot be vented directly into the cabin without further treatment because of the high CO concentrations. One possible solution is to combine a pyrolysis step with catalytic oxidation (combustion) of the effluent gases. This integration takes advantage of the best features of each process, which is insensitivity to product mix, no O2 consumption, and batch processing, in the case of pyrolysis, and simplicity of the product effluent stream in the case of oxidation. In addition, this hybrid process has the potential to result in a significant reduction in Equivalent System Mass (ESM) and system complexity.

One of the major problems associated with solid waste processing technologies is effluent contaminants that are released in gaseous forms from the processes. This is a concern in both biological as well as physicochemical solid waste processing. Carbon dioxide (CO2), the major gas released, does not present a serious problem and there are currently in place a number of flight-qualified technologies for CO2 removal. However, a number of other gases, in particular NOx, SO2, NH3, and various hydrocarbons (e.g. CH4) do present health hazards to the crew members in space habitats. In the present configuration of solid waste processing in the International Space Station (ISS), some of these gases are removed by the Trace Contaminant Control System (TCCS), demands a major resupply. Reduction of the resupply can be effective by using catalyst impregnated carbon nanotubes. For example, NO decomposition to N2 and O2 is thermodynamically favored.

This paper presents the results of a program to develop the next generation Vapor Phase Catalytic Ammonia Removal (VPCAR) system. VPCAR is a spacecraft water recycling system designed by NASA and constructed by Water Reuse Technology Inc. The technology has been identified by NASA to be the next generation water recycling system [1]. It is designed specifically for a Mars transit vehicle mission. This paper provides a description of the process and an evaluation of the performance of the new system. The equivalent system mass (ESM) is calculated and compared to the existing state-of-the art. A description of the contracting mechanism used to construct the new system is also provided.

Pyrolysis is a technology that can be used on future space missions to convert wastes to an inert char, water, and gases. The gases can be easily vented overboard on near term missions. For far term missions the gases could be directed to a combustor or recycled. The conversion to char and gases as well as the absence of a need for resupply materials are advantages of pyrolysis. A major disadvantage of pyrolysis is that it can produce tars that are difficult to handle and can cause plugging of the processing hardware. By controlling the heating rate of primary pyrolysis, the secondary (cracking) bed temperature, and residence time, it is possible that tar formation can be minimized for most biomass materials. This paper describes an experimental evaluation of two versions of pyrolysis reactors that were delivered to the NASA Ames Research Center (ARC) as the end products of a Phase II and a Phase III Small Business Innovation Research (SBIR) project.