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The Deployable Vegetable Production System (VEGGIE) was originally developed as a way to produce fresh vegetables on the ISS with minimal resources. We are reassessing this system for use in lunar habitats to produce palatable, nutritious, and safe fresh food, provide a recreational tool, and provide a platform to support biological life support development by allowing in situ study of crop productivity and air and water revitalization. The VEGGIE system consists of plant growth chambers that can be stowed in a volume less than 10% of their deployed volume, while still providing the light output and root zone capabilities necessary to support high plant productivity rates. The system has significantly reduced logistical and operational requirements compared to other plant growth systems, and is of a modular design to allow logistical flexibility in terms of transport options and placement in a habitat structure.

The ECLSS (Environmentally Controlled Life Support System) project goals are to identify key requirements and guidelines for a Life Support System (LSS) for surface missions based on the Exploration Spirals, to review the various technology options and candidates to fulfill the life support functionality, and to conduct initial trades and assessments at a high level. With the completion of the first six month phase of the project, ORBITEC has generated and shown that for each Exploration Spiral, different LSS architectures are optimal, but when an entire mission model is considered, hybrid systems become more attractive. Also, we can easily show that future spiral requirements should and will influence the technologies and level of closure for earlier spiral developments to reduce overall development and implementation costs, and to increase commonality across the Constellation systems.

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.

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 PESTO (Photosynthetic Experiment System Testing and Operation) experiment flew in the Biomass Production System (BPS) to International Space Station (ISS) on STS-110 (Atlantis) April 8, 2002, and returned on STS-111 (Endeavour) June 19, 2002, after 73 days in space. The ground control was conducted on a two-week delay at Kennedy Space Center in a BPS unit under environmental conditions comparable to ISS. Wheat (Triticum aestivum cv Apogee) and Brassica rapa cv Astroplant were independently grown in root modules for multiple grow-outs. On-orbit harvests, root modules exchanges and primings, seeds imbibitions, and gas and water samplings occurred at periodic intervals; all were replicated in ground controls. Many operations required crew handling and open access to individual chambers, allowing the exchange of microorganisms between the crew environment and the BPS modules.

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 Biomass Production System (BPS) is a double middeck locker payload designed to fly on the Orbiter or Space Station. The BPS contains four plant growth chambers (PGCs) with independent control of temperature, humidity, lighting, CO2, and nutrient solution delivery, allowing for multiple experimental treatments. The BPS provides several features to support on-orbit science activities including the ability to downlink system and science data, video cameras with framegrab capability to collect images for recording plant development, access to plants to perform activities such as pollination or tissue sampling, and gas and fluid sampling ports for sampling of the plant environment. Other capabilities include the ability to conduct CO2 drawdowns, allowing photosynthetic measurements, and the ability to meter plant CO2 and water use. Several technology developments have been evaluated for possible implementation during future upgrades to enhance science capabilities.

The Plant Research Unit development effort will provide a high-performance and highly versatile, controlled environment plant growth chamber for space-based variable gravity science and biotechnology investigations on the International Space Station. Temperature, humidity, atmospheric composition, lighting, and nutrient delivery are the critical parameters to control in an automated and reliable way. Access to plant material on-orbit and maintenance of the unit with minimal crew effort are other major requirements, as is a modular design allowing easy subsystem/technology change-outs so that science capability and maintainability are maximized. The Plant Research Unit (PRU) development program is based on the results of the Biomass Production System (BPS) and many other technical developments, and uses the BPS as a risk mitigation prototype for the PRU.

The objective of the Fluid Handling and Maintenance Experiment (FHAME) is to research, test, and demonstrate liquid/gas phase control in fluid handling subsystems in microgravity. FHAME is currently being developed as a risk mitigation experiment for the upcoming verification and science investigations in plant growth systems, especially the Biomass Production System (BPS) and the Plant Research Unit (PRU). Because FHAME contains controlled fluid handling systems, a large suite of sensors, data acquisition, and visual observation capability, it is well suited for empirical research and testing of movement and to assessing the liquid/gas characteristics for a wide variety of applications. Its first application is to assess fluid priming and gas/liquid characteristics in a particulate bed. FHAME can play a major role in the development of future new nutrient delivery systems for plant growth application in addition to many fluid and gas/liquid empirical research investigations.

The Biomass Production System (BPS) was developed to meet science, biotechnology and commercial plant growth needs in Space. The BPS is a double middeck locker equivalent payload with four internal plant chambers. The chambers can be removed to allow manipulation or sampling of specimens, and are sealed to allow CO2 and water vapor exchange measurements. Each of the growth chambers has independent control of temperature, humidity, lighting, and carbon dioxide levels. Preliminary acceptance and performance testing has demonstrated temperature control within ±1.0°C (between 20°C and 30°C) and humidity control within ±5% (between 60% and 90% RH, depending on ambient temperature and plant load). The fluorescent lighting system provides light levels between 60 and 350 μmol m−2s−1. The CO2 control system controls to the greater of ±50 ppm or ±5% (with plants, as a scrubber is not currently available).

The ASTROCULTURE™ (ASC) middeck flight experiment series was developed to test subsystems required to grow plants in reduced gravity, with the goal of developing a plant growth unit suitable for conducting quality biological research in microgravity. Previous Space Shuttle flights (STS-50 and STS-57) have successfully demonstrated the ability to control water movement through a particulate rooting matrix in microgravity and the ability of LED lighting systems to provide high levels of irradiance without excessive heat build-up in microgravity. The humidity and temperature control system used in the middeck flight unit is described in this paper. The system controls air flow and provides dehumidification, humidification, and condensate recovery for a plant growth chamber volume of 1450 cm3.