Engineering Papers⌕ Search

Engineering topics

Raymond M Wheeler

Publications and source records attributed to Raymond M Wheeler.

48 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Evaluating Microgreens Crop Readiness for Space Production

Microgreens are small-size, nutrient-rich, and fast-grown crops, which are considered as candidates for future space exploration missions. In particular, the ISS, the Lunar Gateway, and Mars and Lunar missions could benefit from growing microgreens to supplement astronaut diets in the near future. Research at NASA’s Kennedy Space Center has focused on (1) the selection of microgreens compatible species, (2) the evaluation of microgreens food safety, (3) the use of passive wicking, on-demand watering, and hydroponics cultivation, (4) simulated microgravity growth, (5) microgreen canopy gas exchange, and (6) harvesting techniques in microgravity. This interactive presentation summarizes this research. Microgreen species will be evaluated for their yield in relationship to the quantity of inputs – water, seeds, substrate, light intensity, photoperiod, crew time – required for their growth; for their organoleptic and sensory factors in order to down select species that are highly acceptable for humans; and for their microbial loads as detected in their growth environment and the food safety metrics of their edible tissue. Passive wicking, on-demand watering, and hydroponic systems are being studied as an efficient way to deliver essential nutrients and water to microgreens, included in a microgravity environment. Growth studies in simulated microgravity (using 3-dimensional clinostats) will assess microgreens growth relative to that in 1g. Gas exchange studies on microgreens canopies in various airflows will assess their photosynthesis and transpiration. Finally, a series of parabolic flights has enabled the evaluation of different harvesting and bagging techniques in microgravity. Indeed, traditional plant harvesting methods (scissors) in microgravity could generate significant microgreen debris in the space station cabin. Two innovative techniques, coupled to a dedicated bagging method, were designed and evaluated against the control, traditional, harvesting technique. This research was supported by grants from NASA KSC’s Independent Research and Technology Development Program, NASA’s Flight Opportunity Program, NASA Postdoctoral Program Fellowships (L.P. & C.J.) supported by NASA’s Space Biology program, and support from NASA’s Human Research Program.

Space Crop Production↗
NASA NTRSDate not supplied

Evaluating Plant Suberin Mutants for Enhanced Water and Nutrient Uptake to Increase Biomass Production Under Elevated CO2 Concentrations

Spaceflight cabin environments such as the International Space Station (ISS) typically have elevated CO2(1500-7000 μmol mol-1), which can affect plant growth and development. On earth, findings from FACE (Free-Air CO2Enrichment) and climate change studies have shown that plants grown at elevated (~ 700 μmol mol-1) CO2contain reduced levels of essential elements such as nitrogen, zinc, and iron. We hypothesized that spacecraft environments with elevated CO2 might likewise result in less nutritious crops for human consumption. Literature showed that quantitative differences in root suberin content could determine the permeability of the internal plant tissues to both water and solutes. To evaluate if there was a correlation between growth under elevated CO2and root suberin content we grew Arabidopsis thaliana, wild type (WT)(col-0), esb1(Enhanced Suberin 1) and horst1(Hydroxylase of Root Suberized Tissue)under ambient (~ 420± 25μmol mol-1) and elevated (800 ± 25, 1600 ± 25, 4000 ± 25 μmol mol-1) CO2concentrations. Comparing the growth of esb1and horst1plants to WT under ambient and elevated CO2concentrations, esb1showed significantly (P-value < 0.05) lower total fresh biomass whereas the horst1exhibited no significant difference. RNA sequencing revealed genes related to water uptake or nutrient availability stress upregulated due to the exposure to 800 and 1600 μmol mol-1CO2.Comparing the elemental composition of leaf tissue between WT and horst1plants grown under elevated CO2,we found an overall decrease in elemental composition for WT, whereas horst1showed an average increase of 30-60 % in the elemental contentsat1600 μmol mol-1compared to plants grown at ambient CO2. In conclusion, our results showed that horst1like modification to edible crops could improve the nutritional (elemental) content to supplement astronaut’s diet.

Anirudha R Dixit↗
NASA NTRSDate not supplied

Microbial Characterization of Heat Melt Compaction for Treatment of Space Generated Solid Wastes

One treatment process in development for solid waste management in space has been the Trash Compaction Processing System (TCPS). Human space mission wastes typically contain large percentages of contaminated wet solid waste. The Heat Melt Compactor (HMC) is being developed to be a multi-function means of water recovery, volume reduction, and the making safe of contaminant-rich trash with the potential for waste stabilization and/or sterilization. To determine the efficacy of the HMC treatment to kill microorganisms in solid waste and remain biologically stable, testing was conducted on three tiles produced by HMC-Gen 2 at Ames Research Center. Samples were shipped to Kennedy Space Center to test for microbial viability after compaction, determine the bio-stability of the HMC disks during storage (43 days), and assess potential airborne contaminate microbial growth on surfaces at low and high humidity conditions. In addition to the products of solid waste processing technologies, there is a concern that the crew might come into contact with hardware surfaces that have been contaminated by microorganisms during waste processing. The extent of microbial surface contamination of waste processing hardware was determined by surface sample swabbing and analysis for total bacterial and yeast counts and cultivable counts of aerobic and anaerobic bacteria, spore-forming bacteria, and fungi. Results indicate that trash processing increased bacterial counts on the surfaces of the compacter. All but one biological indicator spore strip imbedded in the HMC produced tiles were negative for growth after incubation for five days indicating effective sterilization through the heat melt compaction process. Analysis of core samples as well as surface growth of tiles inoculated with Aspergillus niger fungal spores incubated at three levels of humidity indicate that HMC created tiles did not support the proliferation of bacterial and fungal growth.

Mary E Hummerick↗
NASA NTRSDate not supplied

Verification Testing and Veg-05 Tomato Crop Production on the International Space Station

VEG-05 is an experiment to better define best practices for crop production and handling in space. Light can impact the growth habit, yield, nutritional composition, microbial levels, and flavor within crops and VEG-05 used the Veggie facilities on the International Space Station to grow ‘Red Robin’ dwarf tomatoes under different spectral compositions to assess these characteristics. Prior to launch, both a science verification test (SVT), and an experiment verification test (EVT) were conducted. SVT, and a previous fertilizer test, grew plants in both plant pillows and PONDS units and tested different fertilizer treatments, with each test under one of the light conditions. EVT used only plant pillows with the highest fertilizer composition tested, and two Veggie units were utilized. One Veggie had light settings consisting of equal levels of red: blue light while the second Veggie had a 90:10 ratio of red: blue light, both with the addition of ~10% green. For SVT, under the equal red: blue light treatment, fruit ripening in plant pillows was delayed. For EVT we saw fruit ripening earlier, especially in the red-rich treatment. In SVT we had mostly daily watering, and this led to excess water in plant pillows which leaked and caused fungus to grow. We reduced this excess in EVT, however, wilting events occurred. Regardless, more than 10 fruit were produced from each plant on average, with the high red treatment producing slightly heavier fruit. Microbial testing from fruit indicated that fruit were safe for consumption. VEG-05 flight operations ran December 2022 and March 2023, with considerable challenges in watering and unexpectedly low humidity on ISS during critical periods. Only 12 ripe fruit formed, and all were returned. Fruit and other samples are currently being analyzed. This research was co-funded by NASA’s Human Research Program and Space Biology.

Gioia Donna Massa↗
NASA NTRSDate not supplied

Understanding Plant Nitrogen Form Preference Responses to Elevated CO2 Earth and Space Environments

Future long-duration missions to the International Space Station (ISS) and beyond will require a sustainable supply of food to support human crews. The spaceflight cabin environment often contains very high concentrations of CO2, and it is therefore crucial to understand plant responses to elevated CO2 (eCO2) environments. Much focus has been given to plant photosynthetic and performance parameters in response to eCO2, but studies on the effects of eCO2 on nitrogen uptake are poorly understood. Our previous work at The University of Sheffield, UK using novel stable isotope approaches has shown enhanced ammonium uptake and preference compared to nitrate at eCO2 in varieties of spring barley, hypothesized to be an indirect consequence of changes in photosynthesis and photorespiration. However, several varieties did not display altered preference under eCO2 and the universality of this response remains to be understood. In this NASA NPP project, several candidate crop species such as lettuce, radish and tomato will be screened using stable isotopes to assess whether N preference changes in favor of ammonium in response to eCO2 and whether this remains true at super-elevated CO2 (seCO2), which is often experienced on the ISS. Photosynthetic and related measurements will help to disentangle the relationship between these responses and photosynthesis. This work will enable the development of optimized nutrient regimes for candidate crops in space and in future Lunar and Martian habitats and will pave the way for selection of crop varieties adapted to an eCO2 and/or seCO2 environment. Moreover, this research will further our understanding of plant responses to the eCO2 environment brought about by climate change, allowing the development of future-proof crops that will help to maintain food security. This NPP Fellowship is funded by NASA Space Biology.

Luke Leslie Fountain↗
NASA NTRSDate not supplied

Pick-and-Eat Space Crop Production Flight Testing on the International Space Station

Growing fresh, nutritious, palatable produce for crew consumption during spaceflight may provide health-promoting, bioavailable nutrients and enhance the astronaut dietary experience as we move toward longer-duration missions. However, requirements to support consistent growth of a variety of high-quality crops under spaceflight environmental conditions remain unclear. This study explores the potential to grow crops for consumption on the International Space Station (ISS) using Veggie, NASA’s vegetable production chamber system. VEG-04A and VEG-04B were two flight tests with ground components conducted with the leafy green crop mizuna mustard. In each location, mizuna was grown in two Veggie units simultaneously, with the chambers set to different red-to-blue-to-green light formulations. Preflight verification testing with various lighting treatments was conducted to down-select two treatments that contributed to the best desirable growth and sensory qualities in mizuna mustard. For the flight tests, one Veggie was programmed as “red-rich” with an average of 270 μmol m-2 s-1 of 630 nm red light, 30 μmol m-2 s-1 of 455 nm blue light, and 30 μmol m-2 s-1 of 530 nm green light. The second Veggie was “blue-rich” with an average of 150 µmol m-2 s-1 of 630 nm red light, 150 µmol m-2 s-1 of 455 nm blue light, and 30 µmol m-2 s-1 of 530 nm green light. Light quality is known to impact plant growth, nutrition, microbiology, and sensory characteristics on Earth, and the Veggie flight tests examined how these impacts might differ in microgravity. VEG-04A, a 35-day growth test with a single harvest, was initiated in June and harvested in July 2019. VEG-04B, a 56-day test with three harvests from the same plants, assessed sustained productivity. Preflight testing for VEG-04B was conducted after the VEG-04A flight test to improve the operations, approaches, and watering requirements, which resulted in better crop establishment in the VEG-04B flight test. VEG-04B was initiated in October 2019 with harvests at four, six, and eight weeks after initiation. At all of the harvests, the astronauts froze half of the edible plant tissue to return to Earth and weighed the remaining half using the Mass Measurement Device (MMD). Weighed samples were then cleaned with produce-sanitizing wipes, and consenting crew members participated in sensory evaluations of the fresh produce. The remaining sanitized produce was available for crew consumption as desired. Frozen flight samples were returned to Earth for chemical and microbial analyses to assess nutritional quality and food safety. Flight-grown mizuna was generally more acceptable to the crew and had higher nutrient levels, although mizuna grown in the ground control performed better in terms of higher yield and lower microbial load. This presentation will focus on results from the nutritional and sensory analyses, including how nutrients identified as key for supplementing the crew diet varied across lighting treatments, harvest approaches, and spaceflight versus ground conditions. It is our hope that these tests on the ISS will help mitigate the risk of an inadequate food supply for long-duration missions by adding fresh vegetables to the crew diet. This study was supported by NASA’s Human Research and Space Biology Programs through the HERO NNJ13ZSA002N-ILSRA grant solicitation.

Jess Bunchek↗
NASA NTRSDate not supplied

Space Crop Production Gaps and Challenges

As astronauts venture farther from Earth, and stay for longer periods, the space food system will increase in importance. Crop production can supplement a pre-packaged space diet to provide nutrition and dietary variety for space crews. In future missions, bioregenerative approaches may be used to generate a larger percentage of the diet, as well as help to reduce life support system burdens and resupply from Earth. Plants may also provide behavioral health benefits to crew members living in the isolated, confined environment of a space habitat. A number of unique challenges exist for growth of plants in microgravity and on other reduced gravity surfaces like the moon and Mars. Testing plant growth inside the Veggie and Advanced Plant Habitat (APH) chambers on the International Space Station is allowing us to understand the impacts of gravity and spaceflight on crop growth, nutritional content, acceptability, and the importance of plants to astronauts living and working away from Earth. We are also gaining a better understanding of food safety concerns and the behavior of space plant microbiomes and plant pathogens, but major gaps in knowledge remain. As we move from research towards operational space crop production to enable exploration, there are numerous gaps in technology, knowledge, and practice related to space crop growth that must be addressed. Research and development in key focus areas such as effective water and nutrient delivery at variable gravity levels, autonomous plant health monitoring, growth system cleaning and disinfection, and selection of ideal space crops are needed to fill these gaps. Breeding or engineering custom space crops may impact areas including plant growth and development, plant physiology, produce nutrition, organoleptic acceptability, and post-harvest characteristics, and these may further enable space crop production scenarios. Space crop challenges are multifaceted and require diverse interdisciplinary teams working together to develop effective solutions. Solving these requires an array of skill sets from across the biological and physical sciences, engineering, and human social sciences. Solutions to help ensure food security off-Earth may also translate to more sustainable terrestrial crop production approaches, and regular dialog between industry, academia, and government organizations working in related fields benefit all. Additional help can come from engagement with student researchers at various levels through courses, participatory science projects, and open science activities which can provide useful data. Global coordination and integration between space agencies and partners will be essential.

Gioia Donna Massa↗
NASA NTRSDate not supplied

Space Crop Considerations for Human Exploration

NASA has been actively working to both determine how many crops will be needed for early exploration missions as well as updating the “Crop Readiness Level” (CRL) for a library of crops that can be selected for supporting a long-term mission. The Crop Readiness Level (CRL) is modelled after NASA’s Technology Readiness Level (TRL) approach for developing and advancing new technologies for space, first suggested by Barry Finger and published by Wheeler and Strayer [2]. The CRL model has nine levels from “crop identification” to “consumed in space.” The number and variety of crops needed is impacted by both primary factors (nutrition, menu fatigue, behavioral health system resiliency) as well as secondary factors such as ECLSS considerations, crop robustness, and hardware considerations.

Gioia D Massa↗