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Early development of concepts for space structures up to 1000 meters in size was initiated in the early 1960's and carried through the 1970's. The enabling technologies were self-deployables, on-orbit assembly, and on-orbit manufacturing. Because of the lack of interest due to the astronomical cost associated with advancing the on-orbit assembly and manufacturing technologies, only self-deployable concepts were subsequently pursued. However, for over 50 years, potential users of deployable antennas for radar, radiometers, planar arrays, VLBF and others, are still interested and constantly revising the requirements for larger and higher precision structures. This trend persists today. An excellent example of this trend is the current DARPA/SPO ISAT Program that applies self-deployable structures technology to a 300 meter long active planar array radar antenna. This ongoing program has created a rare opportunity for innovative advancement of state-of-the-art concepts.

Plant growth chambers, whether designed for Earth or space applications, should provide the basic means for supporting healthy plant growth of almost any species. These chambers typically satisfy species- and age-specific light, atmosphere composition, water and nutrient requirements. Engineering solutions to satisfy these basic requirements in different plant chambers may vary widely, and each species or each experimental protocol may need individual testing and adaptation of the supporting hardware and science protocols. This paper will summarize the design trades, tests and evaluation experiments conducted to ensure proper hardware functionality and proper hardware / lifeware compatibility for the desired experimental protocols in space.

Aeroponics is the process of growing plants in an air/mist environment without the use of soil or an aggregate media. Aeroponics has contributed to advances in several areas of study including root morphology, nutrient uptake, drought and flood stress, and responses to variations in oxygen and/or carbon dioxide root zone concentrations. The adaptability of the aeroponic process that has benefited researchers makes its application to spaceflight plant growth systems appealing. Greater control of growth parameters permits a greater range of crop performance throttling and the elimination of aggregates or common growth substrates lowers system mass, lessens disease propagation between plants, and can decrease the required crew time for both planting and harvesting.

An event in which electronic insulation consisting of polytetrafluoroethylene undergoes thermodegradation on the Space Station Freedom is considered experimentally and theoretically from the initial chemistry and convective transport through pulmonary deposition in humans. The low-gravity environment impacts various stages of event simulation. Vapor-phase and particulate thermodegradation products were considered as potential spacecraft contaminants. A potential pathway for the production of ultrafine particles was identified. Different approaches to the simulation and prediction of contaminant transport were studied and used to predict the distribution of generic vapor-phase products in a Space Station model.

BioServe Space Technologies has developed and flown a series of miniature habitats to house several different biological specimens and one biochemical experiment. This effort was in support of an educational program, Space Technology and Research Students (STARS), developed by SPACEHAB Inc. The STARS program gives students from around the world a chance to design and conduct their own spaceflight experiments. STARS-Bootes, the payload flown on STS-107, housed a Japanese Medaka fish experiment; a Chinese silkworm experiment; an American Harvester ant experiment; a Carpenter bee experiment from Liechtenstein, an Australian Orb Weaver spider experiment; and a biochemical crystal growth experiment from Israel. Each habitat was custom designed to suit each specimen's individual needs. The habitats provided passive humidity control, lighting, feeding areas, and containment as well as an artificial environment for the specimens to be observed in.

The Autonomous Garden Pod (AG-Pod) is a modular crop production system that can lower the equivalent system mass (ESM) for bioregenerative life support systems. AG-Pod combines existing technologies, many of which are at the technology readiness level (“TRL”) 8 or 9, into a flight-ready system adaptable to many needs from Space Station microgravity plant research to interplanetary transit and planetary surface food production systems. The plant-rated module resides external to the spacecraft pressurized volume and can use natural direct solar illumination. This reduces the ESM of crop production systems by eliminating the use of spacecraft internal pressurized volume and by reducing power and heat rejection resources that would be needed for full artificial lighting. However, lowering of the crop production ESM is also achieved from the use of lightweight structures including composite and inflatable technology.

PGBA, a plant growth facility developed for commercial space biotechnology research, successfully grew a total of 50 plants (6 species) during 10 days aboard the Space Shuttle Endeavor (STS-77), and has reflown aboard the Space Shuttle Columbia (STS-83 for 4 days and STS-94 for 16 days) with 55 plants and 10 species. The PGBA life support system provides atmospheric, thermal, and humidity control as well as lighting and nutrient supply in a 33 liter microgravity plant growth chamber. The atmosphere treatment system removes ethylene and other hydrocarbons, actively controls CO2 replenishment, and provides passive O2 control. Temperature and humidity are actively controlled.

In order to assess the robustness of a Spacecraft Life Support System (LSS) design based on average performance values, criteria such as stability and controllability must be considered under variable and peak system loads. The Exploration Group at the Technische Universität München (TUM) is developing the “Virtual Habitat” computational tool (V-HAB) for exactly this type of investigation. In order to characterize the relative level of confidence for a complex model such as this, a generalized metric was defined which is able to indicate an incremental Model Confidence Level (MCL) throughout the model development process. This paper describes a proposed metric for systematically rating and describing the level of model development, created for and based on the V-HAB simulation.

Accurate root zone moisture control in microgravity plant growth systems is problematic. With gravity, excess water drains along a vertical gradient, and water recovery is easily accomplished. In microgravity, the distribution of water is less predictable and can easily lead to flooding, as well as anoxia. Microgravity water delivery systems range from solidified agar, water-saturated foams, soils and hydroponics soil surrogates including matrix-free porous tube delivery systems. Surface tension and wetting along the root substrate provides the means for adequate and uniform water distribution. Reliable active soil moisture sensors for an automated microgravity water delivery system currently do not exist. Surrogate parameters such as water delivery pressure have been less successful.

The Plant Generic BioProcessing Apparatus (PGBA), a plant growth facility developed for commercial space biotechnology research, has flown successfully on 3 spaceflight missions for 4, 10 and 16 days. The environmental control systems of this plant growth chamber (28 liter/0.075 m2) provide atmospheric, thermal, and humidity control, as well as lighting and nutrient supply. Typical performance profiles of water transpiration and dehumidification, carbon dioxide absorption (photosynthesis) and respiration rates in the PGBA unit (on orbit and ground) are presented. Data were collected on single and mixed crops. Design options and considerations for the different sub-systems are compared with those of similar hardware.

Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies to each of four key functions of the PLSS -- oxygen supply, waste removal, thermal control, and power. The PLSS concepts were evaluated using the ExtraVehicular Activity System Sizing Analysis Tool, software created by NASA to analyze integrated system mass, volume, power and thermal loads.

Until now, NASA's space water reuse research program has not considered the transport of water borne infectious enteric viruses; however, viral diseases probably are a significant concern in long duration space missions. To simplify monitoring and prediction of pathogen distribution, model indicator strains historically have been used. In this research, the male specific RNA coliphage MS-2 is used as a model of enteric viruses due to their similar size and biochemical composition. Inactivation of some water borne enteric viruses by iodine has previously been characterized. In this paper, iodine inactivation of the model coliphage MS-2 in buffered water is compared with earlier bench-scale disinfection survival data and with survival in iodinated simulated shower water used in a test water recycling system.

BioServe Space Technologies is developing a set of habitats which will support various biological specimens and one biochemical experiment. The habitats are being developed to support a spaceflight educational payload called Space Technology and Research Students (STARS). The STARS program entrusts high school students with the development and design of their own spaceflight experiments. Experiments are solicited from various countries and primarily focus on the life sciences. Once selected, all experiments must be accommodated within one middeck locker sized payload, the Commercial Generic Bioprocessing Apparatus.

This paper reports on the approach and progress to refine the estimates of the Mars surface photosynthetically active radiation (PAR) on a global scale that is averaged over a longer time period. While the PAR on Mars has been evaluated previously, the results have been limited in scope either temporally or spatially, such as only at a particular landing site or only over the time span of a few months. Understanding the availability of PAR is important in evaluating the practicality of using greenhouses and/or solar irradiance collectors for growing crops during manned missions to the Martian surface. Until surface investigations can be performed, computational modeling of the surface PAR can help to refine site selection and evaluation of engineering approaches and indicate the most favorable location at which to operate a greenhouse. The proposed approach is to combine multispectral irradiance models with global atmospheric opacity models developed from multiyear observations.

Iodine is being considered for disinfection of recycled hygiene and potable water in Space Station Freedom. Like chlorine, the halogen iodine can form disinfection by-products (DBPs) when used as a disinfectant in waters with dissolved or colloidal organic compounds. Recycled shower and laundry wastewater, urine and condensate from the space cabin atmosphere all have large amounts of dissolved and colloidal organic compounds and may generate iodinated DBP's which can be toxic to humans. We have investigated the formation of iodinated DBP's (IDP's) in model compounds typical of shower wastewater and condensate. The selection of these model compounds and flask experiments to test for IDP formation have been described. Methods for reaction, extraction and analysis for IDP's also have been developed. We have tentatively identified likely organic precursors from recycled water and several iodinated organic compounds formed during the reaction with iodine.

The products of thermodegradation of fluorocarbon polymers (found in electrical insulation) will be toxic to space habitat crews, and the monitoring and detection of such contaminants are important to space environmental health. Experiments are therefore being performed on the thermodegradation of a liquid perfluoroalkane mixture (consisting of perfluorohexanes, C6F14, and −5% perfluoropentane, C5F12), similar in structure to polytetrafluoroethylene (PTFE - Teflon), in atmospheres of varying oxygen concentration. PTFE is a common material used on space vehicles for insulation of wires. When PTFE is thermally degraded, such as from the overheating of a wire and subsequent smoldering of the insulation, it may produce toxic compounds ranging from carbonyl fluoride and hydrogen fluoride through perfluorinated aromatic compounds to ultrafine particles.

In this paper we report on the development of the air quality monitoring and early detection system for an enclosed environment with specific emphasis on manned spacecraft. The proposed monitoring approach is based on the distributed parameter model of contaminant dispersion and real-time contaminant concentration measurements. The Implicit Kalman Filtering (IKF) algorithm is used to generate on-line estimations of the spatial contamination profile, which are used for the air quality monitoring and early detection of an air contamination event. We also solve the problem of the pointwise source identification of the convection-diffusion transport processes. This is done by converting the identification problem into an optimization problem of finding a spatial location and the capacity of a point source which results in the best match of the model-predicted measurements to the observed measurements.

The efficiency and robustness of pilot-automation interaction is a function of the volume of memorized action sequences required to use the automation to perform mission tasks. This paper describes a model of pilot cognition for the evaluation of the cognitive usability of cockpit automation. Five common cockpit automation design errors are discussed with examples.

The increased demand in the area of space life sciences necessitates the need for more experimentation hardware with increased capabilities. Due to the high cost of hardware development for space based research, new hardware should be modular in design and suited to handle a variety of different experiments. The fluid handling systems found in experimentation hardware will often share many of the same requirements for different experiments. A design process that can be used for biological fluid handling systems that cover a wide range of experimentation requirements is proposed. Important parameters to be considered when making a trade study for selection of system components will be discussed. This paper will address topics of current research in space life sciences and describe state of the art hardware that is available or under development for use.

Porous plate dehumidifiers (PPD) and porous tube nutrient delivery systems (PTNDS) are designed to provide a means for accurate environmental control, and also allow for two-phase flow separation in microgravity through surface tension. The technological challenges associated with these systems arise from the requirement to accurately measure and control the very small pressures that typically occur within and across the porous media. On-orbit automated priming or filling of the system in the absence of gravity may be necessary. Several porous plate dehumidifiers and porous tube nutrient delivery systems have been tested and evaluated, and experimental results for engineering design are presented.