Browsing by Author "Spencer, Lashelle"

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Biofilm Resistant Coatings for Space Applications
(48th International Conference on Environmental Systems, 2018-07-08) Li, Wenyan; Hummerick, Mary; Khodadad, Christina; Buhrow, Jerry; Spencer, Lashelle; Coutts, Janelle; Roberson, Luke; Tuteja, Anish; Mehta, Geeta; Boban, Mathew; Barden, Michael
Bacterial biofilms are an important and often problematic aspect of life on earth and in space. Microbial contamination onboard the International Space Station (ISS) continues to pose mission risks, both to crew health and hardware reliability. In order to optimize the design of the future space exploration vehicle for long term missions, new technologies are needed to control the habitat’s microbial environment over multiple years. Among the emerging technologies for combating biofilm, new surface coatings show promise for preventing biofilm formation. This approach aims to interrupt the critical initial step of biofilm formation (cell attachment) through surface modification. When successfully developed, biofilm resistant coatings can eliminate/reduce the need for disinfectants, and avoid the development of “superbugs,” thus offering distinctive advantages for biofilm prevention during long term missions. Initial results at KSC showed that omniphobic coatings are promising candidates as biofilm resistant materials. Parabolic flight experiments also verified their physical properties under microgravity.
Crop Readiness Level (CRL): A Scale to Track Progression of Crop Testing for Space
(49th International Conference on Environmental Systems, 2019-07-07) Romeyn, Matthew; Spencer, Lashelle; Massa, Gioia; Wheeler, Raymond
The development of engineering technologies and hardware for aerospace applications is often tracked on a 1-9 scale of readiness or TRL, with a “1” representing very basic or fundamental principles, and a “9” being flight tested, functional hardware. Preparing to grow crops for supplemental food and eventual life support contributions on space missions faces similar challenges. Nearly 20 years ago, the concept of a “crop readiness level” was suggested at a bioregenerative life support conference held at Kennedy Space Center, but there was little follow up to this. We propose to revive this concept to track the preparation and testing of different crop species for eventual use in the unique environment of space. For the sake of uniformity, we recommend a 1-9 scale, with a “1” being just the identification of a potential crop, followed by some basic horticultural testing, cultivars trials, then testing growth and yield under various controlled environments, progression to more space-like environments and hardware, understanding the nutritional, organoleptic, and food safety aspects of the crop, initial testing in space, and a final stage of growing the crop for food in space (“9”). We attempted to make the scaling logical and progressive, but our main goal is to initiate a dialogue in the space, plant research community to develop a scale for assessing crop readiness.
Design of a Plant Health Monitoring System for Enhancing Food Safety of Space Crop Production Systems
(50th International Conference on Environmental Systems, 2021-07-12) Monje, Oscar; Nugent, Matthew; Finn, Joshua; Spencer, Lashelle; Kim, Moon; Qin, Jianwei; Orourke, Aubrie; Romeyn, Matthew; Fritsche, Ralph
The deployment of fresh crop production systems on spacecraft will require that plant health and food safety is determined without crew intervention. Currently, detecting the occurrence of poor growth in spaceborne plant growth chambers can be accomplished via nondestructive measurements of plant growth rates obtained from photographic analysis of daily increments in leaf area. However, this approach detects changes that may have taken place days earlier before a visible change in leaf area is observed. A prototype hyperspectral and chlorophyll fluorescence imaging system was designed for early symptom detection of plant stress in crop production systems. This prototype imaging system composed of a hyperspectral camera, two LED light banks and a translational arm was designed and constructed. The translational arm moves the camera and the LED light banks over plants growing below. The lighting system uses white LEDs to generate a reflectance signal and UV-A LEDs to induce a chlorophyll fluorescence signal. Plant images obtained with theis prototype plant health monitoring system (PHM) were used to evaluate image processing functions: calculating reflectance images, removing non-plant background pixels, and calculating vegetation indices from hyperspectral reflectance images. Future work will characterize the chlorophyll fluorescence imaging system and identify suitable vegetation indices for detecting common plant stresses (e.g. drought, overwatering, nutrient deficiencies, etc.) encountered in space crop production systems.
Dwarf Tomato and Pepper Cultivars for Space Crops
(49th International Conference on Environmental Systems, 2019-07-07) Spencer, Lashelle; Hummerick, Mary; Stutte, Gary; Sirmons, Takiya; Graham, Thomas; Massa, Gioia; Wheeler, Raymond
Crops for space life support systems and in particular, early supplemental food production systems must be able to fit into the confined volume of space craft or space habitats. For example, spaceflight plant chambers such as Svet, Lada, Astroculture, BPS, and Veggie provided approximately 15-40 cm of growing height for plant shoots. Six cultivars each of tomato and pepper were selected for initial study based on their advertised dwarf growth and high yields. Plants were grown in 10-cm pots with solid potting medium and controlled-release fertilizer to simulate the rooting constraints that might be faced in space environments. Lighting was provided by fluorescent lamps (~300 umol m-2 s-1) and a 16 h light / 8 h dark photoperiod. Cultivars were then down selected to three each for pepper (cvs. Red Skin, Pompeii, and Fruit Basket) and tomato (cvs. Red Robin, Mohamed, and Sweet n’ Neat). In all cases (pepper and tomato), the plants grew to an approximate height of 20 cm and produced between 200 and 300 g fruit fresh mass per plant. In previous hydroponic studies with unrestricted root growth, Fruit Basket pepper and Red Robin tomato produced much larger plants with taller shoots. The findings suggest that high value, nutritious crops like tomato and pepper could be grown within small volumes of space habitats, but horticultural issues, such as rooting volume could be important in controlling plant size.
Effects of Supplemental Far-Red Light on Leafy Green Crops for Space
(2020 International Conference on Environmental Systems, 2020-07-31) Spencer, Lashelle; Wheeler, Raymond; Romeyn, Matthew; Massa, Gioia; Mickens, Matthew
The use of plants to provide food and eventual bioregenerative life support has been studied for nearly 50 years. A logical starting point for early missions like the International Space Station (ISS) is to grow leafy greens to supplement the crew’s diet of packaged foods. In an attempt to expand the list of potential crops, NASA conducted ground studies with eight leafy greens: ‘Dragoon’ lettuce, ‘Extra Dwarf’ pak choi, shungiku, ‘Barese’ Swiss chard, ‘Red Russian’ kale, ‘Toscano’ kale, ‘Amara’ mustard, and ‘Outredgeous’ lettuce, which has been used in prior ground and flight tests with the Veggie Plant Chamber. Plants were grown for 28 days under 320 µmol m-2 s-1 PPFD from LED lights, 3000 ppm CO2, and 23C to simulate an environment similar to the Veggie Plant Chamber aboard ISS. Half of the plants were given ~7 µmol m-2 s-1 and the other half, ~23 µmol m-2 s-1 of supplemental far-red (735 nm). Supplemental far-red light resulted in increased fresh mass yields for some species but not all. This could be due to the relative small amount of far-red photons even in the supplemental treatment. ‘Extra Dwarf’ pak choi and ‘Dragoon’ lettuce produced the highest yields (70-80 g FM/plant) under both lighting regimes. A more consistent response to supplemental far-red light was increased plant canopy cover and increased shoot heights, which may be a consideration for volume constrained systems in space.
Evaluation of Low-Pressure Cold Plasma for Disinfection of ISS Grown Produce and Metallic Instrumentation
(47th International Conference on Environmental Systems, 2017-07-16) Hintze, Paul; Franco, Carolina; Hummerick, Mary; Maloney, Phillip; Spencer, Lashelle
Cold plasma (CP) cleaning is a dry, non-thermal process, which can provide broad-spectrum antimicrobial activity yet reportedly causes little to no damage to the object being sanitized. Since cold plasma uses no liquids, it has the distinct advantage when used in microgravity of not having to separate liquids from the item being cleaned. This paper will present results on an effort to use low pressure CP to disinfect or sterilize materials for in space applications. Exposure times from 0 to 60 minutes and pressures ranging from 0.10 to 1.0 mbar were used to optimize plasma parameters. Tests were done on produce and metal coupons to simulate medical equipment. Escherichia coli was used as the challenge organism on produce and Bacillus pumilus SAFR-32 was used on metal surfaces. Produce testing was not successful, with unacceptable kill rates and the produce being negatively impacted by exposure to the plasma. The plasma caused a 5 log reduction in the number of viable bacteria on metal coupon tests, which placed the number of viable bacteria below the detection limit. This is a very promising result showing that sterilization of medical equipment with cold plasma is feasible. Scanning Electron Microscope images were taken before and after exposure. The images after plasma exposure show that the bacteria spores have been physically affected, as their size has gotten smaller and their appearance has changed.
Hollow Fiber Membrane Bioreactor Systems for Wastewater Processing: Effects of Environmental Stresses Including Dormancy Cycling and Antibiotic Dosing
(46th International Conference on Environmental Systems, 2016-07-10) Coutts, Janelle; Hummerick, Mary; Lunn, Griffin M.; Larson, Brian; Spencer, Lashelle; Kosiba, Michael; Khodadad, Christina; Catechis, John
Hollow fiber membrane bioreactors (HFMBs) have been studied for a number of years as an alternate approach for treating wastewater streams during space exploration. While the technology provides a promising pre-treatment for lowering organic carbon and nitrogen content without the need for harsh stabilization chemicals, several challenges must be addressed before adoption of the technology in future missions. One challenge is the transportation of bioreactors containing intact, active biofilms as a means for rapid start-up on the International Space Station or beyond. Similarly, there could be a need for placing these biological systems into a dormant state for extended periods when the system is not in use, along with the ability for rapid restart. Previous studies indicated that there was little influence of storage condition (4 or 25ºC, with or without bulk fluid) on recovery of bioreactors with immature biofilms (48 days old), but that an extensive recovery time was required (20+ days). Bioreactors with fully established biofilms (13 months) were able to recover from a 7-month dormancy within 4 days (~1 residence). Further dormancy and recovery testing is presented here that examines the role of biofilm age on recovery requirements, repeated dormancy cycle capabilities, and effects of long-duration dormancy cycles (8-9 months) on HFMB systems. Another challenge that must be addressed is the possibility of antibiotics entering the wastewater stream. Currently, for most laboratory tests of biological water processors, donors providing urine may not contribute to the study when taking antibiotics because the effects on the system are yet uncharacterized. A simulated urinary tract infection event, where an opportunistic, pathogenic organism, E. coli, was introduced to the HFMBs followed by dosing with an antibiotic, ciprofloxacin, was completed to study the effect of the antibiotic on reactor performance and to also examine the development of antibiotic-resistant communities within the system.
Legume Crop Testing for Space
(2023 International Conference on Environmental Systems, 2023-07-16) Spencer, Lashelle; Gooden, Jennifer; Curry, Aaron; Sirmons, Takiyah; Romeyn, Matthew; Wheeler, Raymond
Long-duration missions beyond low-Earth orbit will encounter challenges in maintaining adequate nutrition and acceptability in the food system. In situ production of fresh produce can supplement nutrient deficiencies in the prepackaged diet. Currently there is a relatively small number of crops that can be reliably grown in space for space crop production efforts. Recent challenges with Veggie plant growth technical demonstrations, such as interveinal chlorosis and necrosis of Tokyo Bekana Chinese cabbage when grown under elevated CO2 (~3000 ppm) and narrow-band LED lighting, have highlighted the necessity to conduct rigorous ISS-relevant crop screening on the ground. Additionally, crops should be selected to address specific nutritional deficits as identified by the Human Research Program, with an emphasis on having a diversity of crops to meet nutritional requirements and crew acceptability. To achieve this, the concept of Crop Readiness Level (CRL) has been developed to gauge readiness of crops for spaceflight applications. This includes assessing environmental compatibility, food safety considerations, relevant nutritional analysis, and sensory analysis. Recent testing at Kennedy Space Center has focused on the advancement of a variety of legumes along the CRL. Five varieties of peas (Pisum sativum) ‘Tom Thumb’, ‘Royal Snap’, ‘Yellow Snap’, ‘ES Thick Pod 404-51-2’ and ‘ES Thick Pod 404-52-2-1’ and three varieties of bean (Phaseolus vulgaris); ‘Antigua’, ‘4921 snap’, and ‘Velour Purple’ were grown under 300 µmol m-1 s-1 PPFD from LED lights, 3000 ppm CO2, and 23°C to simulate an ISS environment. Crops will be harvested and yield, baseline nutritional analysis (Vitamins B1, C, K; elemental analysis; proximate analysis) and sensory evaluation will be performed. These baseline data are essential to selecting candidate crops for future missions in addition to assessing crop production hardware and changes in environmental conditions on future crop performance and nutritional quality.
New Frontiers in Food Production Beyond LEG
(49th International Conference on Environmental Systems, 2019-07-07) Monje, Oscar; Dreschel, Tom; Nugent, Matthew; Hummerick, Mary; Spencer, Lashelle; Romeyn, Matthew; Massa, Gioia; Wheeler, Raymond; Fritsche, Ralph
New technologies will be needed as mankind moves towards exploration of cislunar space, the Moon and Mars. Although many advances in our understanding of the effects of spaceflight on plant growth have been achieved in the last 40 years, spaceflight plant growth systems have been primarily designed to support space biology experiments where the mission ended after the completion of a series of experiments. Recently, the need for a sustainable and robust food system for future missions beyond LEO has identified gaps in current technologies for food production. The goal is to develop safe and sustainable food production systems with reduced resupply mass and crew time than current systems. New soilless water and nutrient delivery systems are needed to avoid constant resupply of bulky single-use porous media. Autonomous plant health and food safety monitoring systems are needed for to ensure that the food produced is suitable for supplementing crew diets with fresh and nutritious salad crops. New plant species and cultivars with improved contents of antioxidants, vitamins, and minerals when grown elevated CO2 concentrations found in spacecraft. These improvements in food production technologies will enable the design of more robust and sustainable life support systems for manned exploration missions beyond Low Earth Orbit.
Novel Microgreen Crop Testing for Space
(2023 International Conference on Environmental Systems, 2023-07-16) Spencer, Lashelle; Spencer, Lashelle; Gooden, Jennifer; Curry, Aaron; Romeyn, Matthew; Wheeler, Raymond; Sirmons, Takiyah
Long-duration missions beyond low-Earth orbit will encounter challenges in maintaining adequate nutrition and acceptability in the food system. In situ production of fresh produce can supplement nutrient deficiencies in the prepackaged diet. Currently there is a relatively small number of crops that can be reliably grown in space for space crop production efforts. An intriguing area of new investigation is into novel types of microgreens that have the potential to be sources of calories, fat, carbohydrates, and protein. These sources of nutrition are not obtainable in significant quantities with current pick and eat crops. Many microgreen cultivars are also sources of nutrients of interest, such as Vitamins B1, C, K and elements such as potassium. Microgreens should be selected to address specific nutritional deficits as identified by the Human Research Program, with an emphasis on having a diversity of crops to meet nutritional requirements and crew acceptability. To achieve this, the concept of Crop Readiness Level (CRL) has been developed to gauge readiness of crops for spaceflight applications. This includes assessing environmental compatibility, food safety considerations, relevant nutritional analysis, and sensory analysis. Recent testing at Kennedy Space Center has focused on the advancement of a variety novel microgreens along the CRL. These varieties were grown under 150 µmol m-1 s-1 PPFD from LED lights, 3000 ppm CO2, and 23°C to simulate an ISS environment. Crops will be harvested and yield, baseline microbiological, nutritional analysis (Vitamins B1, C, K; elemental analysis; proximate analysis) and sensory evaluation will be performed. These baseline data are essential to selecting candidate crops for future missions in addition to assessing crop production hardware and changes in environmental conditions on future crop performance and nutritional quality.
Production, Nutritional and Organoleptic Analysis of Solanaceous Crops for Space
(50th International Conference on Environmental Systems, 2021-07-12) Spencer, Lashelle; Sirmons, Takiyah; Romeyn, Matthew; Wheeler, Raymond
Missions beyond low-Earth orbit will encounter challenges in maintaining adequate nutrition and acceptability in the food system. In situ production of fresh produce can supplement nutrient deficiencies in the prepackaged diet. Several tomato and pepper varieties were evaluated with the goal of determining those with the best growth, nutrition, and organoleptic potential for use in a pick and eat salad crop production system. Cultivars of tomato (Solanum lycopersicum); �Red Robin�, �Sweet N Neat�, �Golden Heirloom�, �Ground Dew�, �Ground Jewel�, �Tomato 851� and cultivars of pepper (Capsicum annuum); �Numex Espa�ola Improved�, �Pompeii�, �Mohawk�, �Baby Bell�, �Big Jim Heritage� and �Bulgarian Carrot� were grown under 300 �mol m-1 s-1 PPFD from LED lights, 3000 ppm CO2, and 23�C to simulate an ISS environment. Nutritional analysis of all crops and sensory evaluation of tomato was conducted. �Bulgarian Carrot� was the hottest pepper at 8217 Scoville Heat Units, containing the highest amount of magnesium (0.042%), phosphorus (0.087%), potassium (0.619%), protein (3.94%) and Vitamin K1 (0.24�g/g). �Pompeii� had the highest Vitamin B1; 0.230 mg/100g. �Sweet N Neat� tomato had twice as much lycopene (92.5�g/g) than the all other red tomatoes and the highest amount of potassium (0.305%). �Ground Jewel� tomato had the highest Vitamin C content (25.6 mg/100g), however, several pepper varieties had significantly more; �Mohawk�, �Pompeii� and �Bulgarian Carrot contained 63.7, 46.2 and 41.9 mg/100g Vit. C, respectively. All six tomato cultivars received �passing� overall acceptability organoleptic scores with �Red Robin� tomato achieving the highest score (8.04). Several pepper varieties suffered from severe intumescence injury, therefore fruit production under these environmental conditions was limited, and insufficient for organoleptic testing. These baseline data are essential to selecting crops for future missions and assessing the impacts of new crop production hardware and changes in environmental conditions on future crop performance and nutritional quality.
Recovery of Nutrients from Inedible Biomass of Tomato and Pepper to Recycle Fertilizer
(47th International Conference on Environmental Systems, 2017-07-16) Lunn, Griffin; Stutte, Gary; Spencer, Lashelle; Hummerick, Mary; Wong, Les; Wheeler, Raymond
Plants can be used as a source food, oxygen, and help remove carbon dioxide for human life support in space. But to grow these plants will require sufficient nutrients (fertilizer). This fertilizer can be stowed and resupplied, but this imposes a mass cost to the mission. Depending on the crop, a large portion of the biomass will be inedible. This inedible biomass contains various nutrients that can be recycled for subsequent crops, hence reducing the need for imported fertilizer. Previous studies demonstrated that continuously stirred tank bioreactors and composters can be used to retrieve many of these nutrients. This can provide a liquid effluent that is easily used in hydroponic systems. We explored various approaches to achieve more complete recovery of nutrients from inedible biomass, and focused our testing on pepper and tomato leaves and stems. Approaches included water leaching, acid treatment, microbial degradation, photocatalytic oxidation, thermal methods, and various combinations of these. Acid (0.1 M or 1.0 M HCl) pretreatment with contact times as low as 10 minutes proved effective in combination with many approaches. To date, these treatments have not been able to recover more than 70% of some macronutrients regardless of combination of treatments. This recalcitrant inorganic fraction needs additional study to explore cost effective approaches for closing the mass loop for crop growth systems.
The Microbiology of Microgreens Grown in Controlled Environment Chambers under ISS Conditions
(51st International Conference on Environmental Systems, 2022-07-10) Hummerick, Mary; Curry, Aaron; Gooden, Jennifer; Spern, Cory; Spencer, Lashelle; Romeyn, Matthew; Fischer, Jason
Microgreens have been identified as a new type of pick-and-eat salad crop that can be utilized in space crop production systems. The majority of traditionally grown leafy green crops can be grown as microgreens, in addition to crops such as legumes, sunflower, buckwheat, most herbs, and corn, presenting hundreds of microgreen crop options. Notably, microgreens are nutrient dense, high in beneficial compounds like antioxidants, Vitamins C and K, and exhibit a variety of desirable flavors and textures. The short growth cycles (7-14 days), low water requirements and volume optimization potential make them a viable option for sustainable production of nutritious and flavorful crops in space. The crop production team at Kennedy Space Center is investigating the food safety aspects of microgreens grown under spaceflight relevant conditions for crew consumption. Microbiological analysis and screening for potential foodborne pathogens was performed on over 20 varieties of microgreens that have demonstrated positive horticultural attributes. Additionally, a comparison of microgreens grown hydroponically under ISS environmental conditions and similar varieties from local markets was completed to collect baseline data on the microbial load on microgreens. In an effort to improve microgreen quality, strategies to reduce the microbial load were tested, including bulk seed sanitization, harvest age, exposure to high blue light, and post-harvest chemical disinfection. The efficacy of a citric acid-based produce wash currently used for ISS grown produce and 1% H2O2 were investigated at different exposure times for reduction in bacterial and fungal counts on a variety of microgreens. Limited log reduction was achieved depending on exposure time. Our testing also demonstrated that seed sanitization impacted microbial load on microgreens and systems.