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The first spaceflight opportunities for Advanced Life Support (ALS) Project testing with plants will likely occur with missions on vehicles in Low Earth Orbit, such as the International Space Station (ISS). In these settings, plant production systems would likely be small chambers with limited electrical power. Such systems are adequate for salad-type crops that provide moderate quantities of fresh, flavorful foods to supplement the crew diet. Successful operation of salad crop systems in the space environment requires extensive ground-based testing with horticultural methodologies that meet expected mission constraints. At Kennedy Space Center, cultivars of radish, onion, and lettuce are being compared for performance under these “flight-like” conditions.

A reliable nutrient delivery system is essential for long-term cultivation of plants in space. At the Kennedy Space Center, a series of ground-based tests are being conducted to compare candidate plant nutrient delivery systems for space. To date, our major focus has concentrated on the Porous Tube Plant Nutrient Delivery System, the ASTROCULTURE™ System, and a zeoponic plant growth substrate. The merits of each system are based upon the performance of wheat supported over complete growth cycles. To varying degrees, each system supported wheat biomass production and showed distinct patterns for plant nutrient uptake and water use.

Under certain nutrient solution management practices in hydroponic systems, sweetpotato [Ipomoea batatas (L.) Lam.] plants can exhibit excessive shoot growth and reduced storage root yield. An experiment was conducted which compared sweetpotato production in nutrient film technique (NFT) systems either with daily nutrient solution replenishment + real-time pH control or with nutrient solution replenishment 3-times per week + periodic pH adjustment. Results showed that replenishment of nutrient solution on a daily basis produced excessive foliage growth with very little storage root production. Nutrient solution replenishment 3-times per week produced manageable vine growth and respectable storage root yields.

A BRIC (Biological Research In a Canister) experiment to investigate the effects of reduced gravity at the molecular level using Arabidopsis has been initiated. To ensure an efficient BRIC experiment, a series of ground-based studies have been conducted. These studies were designed to determine: 1) the ideal seed density to obtain enough plant tissue from a single canister; 2) optimum germination surface for tissue recovery after freezing in liquid nitrogen; 3) yield and quality of mRNA from small amounts of tissue; 4) time point to freeze the seedlings; and 5) changes in gene expression that may be caused by stresses during launch.

A long-duration lunar outpost will rely entirely upon imported or preserved foods to sustain the crew during early Lunar missions. Fresh, perishable foods (e.g. salad crops) would be consumed by the crew soon after delivery by the re-supply missions, and can provide a supplement to the diet rich in antioxidants (bioprotectants) that would serve as a countermeasure to radiation exposure. Although controlled environment research has been carried out on the growth of salad crops under a range of environmental conditions, there has been no demonstration of sustainable production in a flight-like system under conditions that might be encountered in space. Several fundamental challenges that must be overcome in order to achieve sustained salad crop production under the power, volume and mass constraints of early Lunar outposts include; growing multiple species, sustaining productivity through multiple plantings, and minimizing time for crew operations.