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Water recovery is essential for long-duration space exploration transit and outpost missions. Primary stage wastewater recovery systems partially satisfy this need, and generate concentrated wastewater brines that are unusable without further processing. The Enhanced Brine Dewatering System (EBDS) is being developed to allow nearly complete recovery of water from Lunar Outpost wastewater brines. This paper describes the operation of the EBDS and discusses the development and testing of the major functional materials, components, and subsystems, including the wastewater brine ersatz formulations that are used in subsystem testing. The assembly progress of the EBDS full system prototype is also discussed, as well as plans for testing the prototype hardware.

A modular and scalable Dense Medium Plasma Water Purification Reactor was developed, which uses atmospheric-pressure electrical discharges under water to generate highly reactive species to break down organic contaminants and microorganisms. Key benefits of this novel technology include: (i) extremely high efficiency in both decontamination and disinfection; (ii) operating continuously at ambient temperature and pressure; (iii) reducing demands on the containment vessel; and (iv) requiring no consumables. This plasma based technology was developed to replace the catalytic reactor being used in the planned International Space Station Water Processor Assembly.

A prototype packed bed convective dryer has been studied for use in an energy-efficient closed air-loop heat-pump drying system for astronaut cabin waste. This paper presents a transient continuum model for the heat and mass transfer between the air and wet ersatz trash in the cylindrical drying vessel. The model is based on conservation equations for energy and moisture applied to the air and solid phases and its formulation includes the unique waste characteristic of having both dry and wet solids. It incorporates heat and mass transfer coefficients for the system measured on an ersatz trash in the dryer vessel, and experimentally determined moisture sorption equilibrium relationship for the wet material. The resulting system of differential equations is solved by the finite-volume method as implemented by the commercial software COMSOL. The validated model will be used in the optimization of the entire closed-loop system consisting of dryer, condenser, and heat-recovery modules.

The Biomass Production System (BPS) was flown on the ISS for 73 days as part of the Increment 4 mission. To obtain maximum benefit from the long mission duration, numerous manual crew procedures were incorporated into the BPS experiments. These procedures included gas sampling, root module priming, harvesting, pollination, filter cleaning, water refill, and water sampling. On-orbit crew assessments were filled out for each of these procedures to evaluate the ability of BPS to accommodate them. The assessment asked questions about each phase of an activity and solicited recommendations for improvements. Further analysis of most procedures was provided by detailed video made on-orbit and multiple post-flight crew debriefs. Most assessments indicated no need for improvements, but a number of crew suggestions will be incorporated into hardware and procedure updates.

The Biomass Production System, recently flown on the ISS for 73 days, demonstrated significant advancements in functional performance over previous systems for conducting plant science in microgravity. The Biomass Production System (BPS) was the first flight of a system with multiple, independently controlled, plant growth chambers. Each of four chambers was controlled separately with respect to temperature, humidity, light level, nutrient level, and CO2, and all were housed in a double Middeck locker-sized payload. During the mission, each of the subsystems performed within specification. This paper focuses on how the performance of the BPS hardware allowed successful completion of the preflight objectives.

Based upon the development experience and flight heritage of the Biomass Production System, the Plant Research Unit embodies the next generation in the evolution of on-orbit plant research systems. The design focuses on providing the finest scientific instrument possible, as well as providing a sound platform to support future capabilities and enhancements. Performance advancements, modularity and robustness characterize the design. This new system will provide a field ready, highly reliable research tool.

The longest BPS ground test to-date was the BPS Mission Verification Test done to provide a high fidelity end-to-end system test of BPS hardware and operations. This test took place at Kennedy Space Center from 4/9/01 to 6/21/01. The BPS temperature and humidity control, atmospheric control, lighting, and nutrient delivery systems performed within specifications. Ambient temperature conditions for the test ranged from 22°C to 28°C. Temperature systems performed well over the full range of ambient conditions and temperature setpoints were maintained throughout the test. Humidity setpoints were maintained within specification under nominal conditions; however, drift in humidity was observed during high ambient temperatures with large plant load conditions, and during CO2 drawdowns. CO2 levels in the wheat chambers were within ± 10% of setpoint under nominal conditions. Several automated CO2 drawdowns and CO2 cylinder changeouts were successfully completed.

As space hardware continues to grow in complexity, the demands on crews expected to be able to operate and maintain this equipment continue to grow. In terms of the International Space Station, the demands on the crew have been further increased by the reduction in crew capacity from the originally planned seven members down to three. This situation has prompted the need to find new ways of training that can meet these demands. In particular, just-in-time training techniques promise to enable crew members to correctly execute procedures that they have never performed before on equipment that they are only marginally familiar with or perhaps have never even seen before. To enable crews to work with unfamiliar procedures or equipment, we believe that it is necessary to employ a highly visual approach to convey the complex spatial information that is often involved.

The Plant Research Unit (PRU) is the Space Station Biological Research Program plant growth facility being developed for the International Space Station. The plant habitat is designed for experiments in near-zero gravity or it can be rotated by the ISS Centrifuge for experiments at any gravity level from microgravity to twice Earth's gravity. Plant experimentation will be possible in multiple Plant Research Units at one time, isolating the effect of gravity on the biological specimens. The PRU will provide and control all aspects of a plant's needs in a nearly closed system. In other words, the shoot and root environments will not be open to the astronaut's environment except for experiment maintenance such as planting, harvesting and plant sampling. This also means that all lighting, temperature and humidity control, nutrient delivery, and air filtering and cleaning must be done in a very small volume, with very little mass and power usage and with minimal crew time.

The Advanced Animal Habitat (AAH) represents the next generation of Space Station based animal research facilities. Building upon previously developed flight hardware and experience, the AAH offers greatly enhanced system capabilities and performance. The design focuses upon the creation of a robust and flexible platform capable of supporting present and future experimental needs. A modular packaging and distributed control architecture leads to increased system adaptability and expandability. The baseline configuration includes group housing capability for up to six rats with automated food and water delivery as well as waste collection. Animals are continuously monitored with three cameras during both day and night cycles. The animals can be accessed while on-orbit through the Life Sciences Glovebox to perform a wide variety of experimental protocols.

The Advanced Animal Habitat (AAH) and Plant Research Unit (PRU) are two major components of the Space Station Biological Research Project (SSBRP). These two habitats are currently under development by Orbital Technologies Corporation (ORBITEC). Science Evaluation Units (SEUs) have been developed for each of these habitats to allow investigators to plan and test flight experiments on the ground using hardware that is functionally similar to the flight versions of the AAH and PRU. The SEUs also contain key functionality that makes them excellent science tools for general laboratory experiments that are not related to flight experiments.

The Advanced Animal Habitat (AAH) represents the next generation of Space Station based animal research facilities. Care has been taken to protect the ISS crew from exposure to the hazardous biological materials contained within the AAH. These materials include rat feces, urine, dander, and odor. The approach to containing biological materials relies on collecting the solid and liquid waste, providing physical barriers between the waste and the crew environment, maintaining negative pressure within the specimen environment with respect to the crew environment, and providing odor filtration of air exchanged between the specimen and crew environments. These protections will be in place during all modes of AAH operation.

In-situ resource utilization (ISRU) is an important part of current mission architectures for both a return to the Moon and the eventual human exploration of Mars. ORBITEC has developed and demonstrated an innovative direct energy processing approach for carbon-reduction of lunar and Martian regolith that can operate in a nearly closed-loop manner. Carbon-reduction of regolith produces oxygen and a variety of other useful products, including silicon, iron and glass ceramic materials. In addition, various ISRU propulsion technologies that utilize lunar and Martian resources have been developed and demonstrated. Work is also being conducted with the USDA on techniques to use biomass and waste materials to manufacture items such as shelters, furniture, filters and paper. Atmospheric carbon dioxide on Mars would be used to support the production of biomass in excess of life support needs to be used as the raw material to manufacture useful products on-site.

A common question for students to ask educators is “When am I ever going to use this?” An excellent way to answer that question is to demonstrate how interrelated many subjects are. At ORBITEC in Madison, WI, we are developing systems to help teachers demonstrate the exciting interrelationships of science, math and technology using activities related to growing plants in space. We are developing two portable plant growth systems that integrate multiple disciplines, enriching students’ classroom experiences. Each portable growth unit is based on similar principles. The Space Garden and Biomass Production Education System (BPES) are growth units for indoor use that utilize a bellows technology to create a greenhouse-like environment. The Space Garden is a personal growth unit that a student can use individually while the BPES will be 0.25 m2, allowing larger-scale experimentation. The Space Garden will be best used in classrooms of grades four through seven.

The design of reliable systems is especially important when they are intended for use on the International Space Station (ISS). Limits on crew time and the sensitive nature of experiments being performed require that the systems used to support those experiments have a very low probability of failure. The Plant Research Unit (PRU) has very strict reliability requirements and thus provides a good example of how the challenge of designing reliable systems can be met.

High reliability and system flexibility are driving factors in the Plant Research Unit development. Proper selection of the unit electrical and software control architecture is fundamental to achieving these goals. Key features of the PRU control design include the use of a real time operating system for main process control, dynamic power management, a distributed control architecture and subsystem modularity. The chosen approach will allow future modifications and improvements to be incorporated at the subsystem level with minimal impact to the unit overall. Hardware fault tolerance and redundancy enhance system reliability.

The International Space Station (ISS) presents unique challenges in the field of maintainability engineering. Due to limited training time on earth and crew time in space, systems must be designed for ease of operation and maintenance. The Plant Research Unit (PRU), an advanced plant growth facility, is required to operate on orbit with minimal crew interaction for maintenance. The PRU has been allotted one hour per increment for corrective maintenance, which consists of replacing Orbital Replacement Units (ORU) or incorporating workarounds. Designing highly maintainable systems is not possible without incorporating the principles of human factors engineering. The PRU has met the strict crew time requirements by combining those principles with maintainability engineering analysis techniques and then integrating them in the design process.

As spaceflight hardware becomes increasingly complex, ever greater demands are placed on astronauts’ training capacity. In addition, astronauts are being asked to conduct unplanned operations with minimal or no training, and long duration operations preclude the ability to thoroughly train before flight on many operations. This trend will be more pronounced as we approach remote operations on the moon and Mars in the Exploration era. In response, Orbital Technologies Corporation has developed an interactive and collaborative 3D simulation training solution for payloads and International Space Station systems. This portable web-based training system provides flexible, efficient and effective pre-flight, real-time and operational training support. Unlike virtual reality systems, this next generation simulation can also be used for remote or just-in-time procedural training between ground-based experts and astronauts in space due to its low file size and collaboration capability.

As part of the PRU project a new plant lighting system has been developed. System design focused on light source development, chamber optical performance improvements and electronics optimization. Central to the lighting system performance is a high density LED Light Engine, enabling increased spectral diversity, higher irradiance levels, enhanced uniformity and improved efficiency. Chamber wall surface materials were tested to minimize the vertical irradiance gradient and improve planar uniformity. Total lighting system efficiency was improved through the use of switching converter LED drive circuitry. As an alternative to the LED light source, an advanced planar fluorescent lighting source has also been developed.