Veggie PONDS (Veggie PONDS Validation) - 07.19.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Organisms grow differently in space, from single-celled bacteria to plants and humans. Future long-duration space missions will require crew members to grow their own food. Therefore, understanding how plants respond to microgravity and demonstrating the reliable vegetable production on orbit are important steps toward that goal. Veggie PONDS uses a newly developed passive nutrient delivery system and the Veggie plant growth facility aboard the International Space Station (ISS) to cultivate lettuce and mizuna greens which are to be harvested on-orbit, and consumed, with samples returned to Earth for analysis.
Science Results for Everyone
Information Pending

The following content was provided by Ye Zhang, Ph.D., Howard G. Levine, Ph.D., and is maintained in a database by the ISS Program Science Office.
Experiment Details

OpNom: Veggie Ponds

Principal Investigator(s)
Ye Zhang, Ph.D., NASA Kennedy Space Center, Cape Canaveral, FL, United States
Howard G. Levine, Ph.D., NASA Kennedy Space Center, Cape Canaveral, FL, United States

Co-Investigator(s)/Collaborator(s)
Gioia D. Massa, Ph.D., NASA Kennedy Space Center, Cape Canaveral, FL, United States

Developer(s)
NASA Kennedy Space Center, Cape Canaveral, FL, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
NASA Research Office - Space Life and Physical Sciences (NASA Research-SLPS)

Research Benefits
Space Exploration, Earth Benefits, Scientific Discovery

ISS Expedition Duration
February 2018 - August 2018

Expeditions Assigned
55/56

Previous Missions
Veg-1A, Veg-01B, Veg-01C Veg-03A, Veg-03B, Veg-03C, Veg-03D, Veg-03E, Veg-03F

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Experiment Description

Research Overview

  • Veggie PONDS is a direct follow-on to the Veg-01 and Veg-03 hardware and plant growth validation tests. The primary goal of the Veggie PONDS hardware validation test is to demonstrate plant growth in a newly developed plant growing system, PONDS (Passive Orbital Nutrient Delivery System).
  • One of the challenges of growing plants on orbit is to deliver water and nutrients efficiently in the microgravity environment. Although plant pillows performed well in the Veg-01 and Veg-03A-D missions, new plant growth hardware is needed for growing a variety new crops, from larger leafy vegetables, to fruit crops, such as tomato, which is planned to be grown in the Veg-05 mission. PONDS units have features that are designed, not only to mitigate microgravity effects on water distribution, but also to increase oxygen exchange and provide sufficient room for root zone growth.
  • Two leafy green crop varieties, ‘Outredgeous’ red romaine lettuce and mizuna mustard are cultivated. Both varieties have been successfully grown using plant pillows in the Veggie plant growth facility on the ISS. .
  • The completion of the first runs of Veg-01 and Veg-03 helped investigators compare root zones with two substrate particle sizes to determine water and root distribution to provide recommendations for future Veg series investigations. Veg-03 A-C tested different crop harvest scenarios with cut-and-come again repetitive harvesting and showed that astronauts could produce twice as much produce with the same amount of starting materials. Additionally, Veg-03 B and C tested a new crop, ‘Tokyo bekana’ Chinese cabbage. Ongoing Veg-03 D-F missions are currently testing mixed growth of three different leafy greens and different harvest schedules in the Veggie plant growth facility. In Veggie PONDS, the performance of the PONDS system is tested to validate whether improved water and nutrient delivery can produce more uniform plant growth. This is important for future new crops which may have more stringent water delivery demands.
  • Shoot tissue samples collected from these missions provide information on the microbial load of the plants. Both plant pillows and PONDS units are single use items, thus reducing the chances of microbial contamination of the Veggie facility and produce. A major aspect of these Veggie missions was to collect baseline microbial data from plants and plant growth hardware in the Veggie facility on ISS. Ground testing has demonstrated very low microbial levels on lettuce plants and relatively high microbial levels on mizuna plants grown in the ground Veggie facility. No specific human pathogen have been found in any ground of flight samples. Discussions with space microbiologists, flight surgeons, and space food technologists indicate that the crew should be able to consume the fresh produce produced in space with precautionary sanitizing using produce sanitizing wipes since microbial levels in the returned samples were sufficiently low. These baseline data collected from the Veg-01, Veg-03, and Veggie PONDS flight experiments are a valuable resource for future Veg series investigations.
  • Photographs taken during these missions help in the assessment of plant growth rates, as well as evaluation of plant health. The temperature and relative humidity recorded real-time by data loggers within the Veggie facility provide important environmental data. Crew questionnaires provide insight into the appropriateness and thoroughness of the crew procedures for the Veggie facility and plant growth operations.
  • The information gained in these missions provides data on future procedural optimization, hardware upgrades, and horticultural options, as Veggie becomes an integral part of ISS expeditions in the future.

Description

The overall goal of Veggie PONDS is to further demonstrate proof-of concept for a new plant growth hardware in addition to the Veggie plant growth chamber and the planting pillows. The concept of PONDS was first developed and patented at NASA Kennedy Space Center (KSC). This research builds upon hardware development via the NASA KSC science team, TechShot, and commercial partner Tupperware, for the initial prototype PONDS units with subsequent hardware development for next-generation units.
 
Through numerous tests the Veggie PONDS science team has redesigned the pillow concept and selected growth media and fertilizers, plant species, materials, and protocols for using the PONDS concept in Veggie to grow healthy plants that can provide crew with food and recreation. The PONDS concept is designed to be low mass, modular, require no additional energy and very low maintenance, and to interface with the Veggie hardware. PONDS units can accommodate a wide variety of plant types and different types of growing media.
 
The primary goal of the Veggie PONDS testing is to demonstrate plant growth in the Veggie hardware using Mizuna and lettuce as test crops. Plants are grown in mixtures of two different sizes of arcillite, a calcined clay media. The media size is one of the factors to affect water and root distribution and this experiment will provide recommendations for future Veggie PONDS investigations.
 
Shoot tissue samples also provide information on any growth anomalies when compared with ground controls. Photographs are used to assess plant growth rates and plant health. A data logger records the environment within the Veggie hardware. Crew questionnaires provide insight into the appropriateness and thoroughness of the crew procedures for Veggie hardware and plant growth operations. PONDS units are single use and thus reduce the chances of microbial contamination of the Veggie hardware and produce.
 
A major aspect of the proof of concept flight, Veggie PONDS, is to collect baseline microbial data from plants and PONDS grown on ISS. Ground testing and Veg-01 and Veg-03 results have demonstrated very low microbial levels on lettuce plants grown in Veggie-relevant conditions. Discussions with space microbiologists, flight surgeons, and space food technologists at the NASA Johnson Space Center in Houston, TX indicate that if microbial levels are sufficiently low, the crew could consume the fresh produce without sanitizing. For crops that naturally have higher levels of microorganisms (e.g. radishes, which grow in contact with water and nutrients), a space-rated produce sanitation method must be developed and tested.
 
The baseline data collected from Veg-01, Veg-03, and Veggie PONDS flights serves as a resource for future Veggie investigations such as the upcoming Veg-04 and Veg-05 scientific investigations. This information provides data on procedural optimization, hardware upgrades, or horticultural options.

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Applications

Space Applications
Future manned exploration missions into deep space require fresh food supplies to supplement crew diets, which means growing crops in space. Previous investigations focused on improving productivity in controlled environments, but the limited quarters of the space shuttle and International Space Station made it difficult to conduct large-scale crop production tests. The Veggie PONDS investigation expands on previous validation tests of the new Veggie hardware, which can potentially allow crew members to grow a variety new crops from new leafy greens to dwarf fruit crops in space. Tests also aim to determine and monitor microbiome population changes that are present in space-grown crops, providing baseline data for future food production efforts.

Earth Applications
Results from the Veggie PONDS investigation contribute to basic research on plant cultivation, benefiting agricultural and biomass production efforts on Earth. The technology used in the Veggie crop production system could be adapted for use in areas from roof top gardens in densely populated areas where there is little room for growing plants, to horticultural therapy for individuals who would otherwise be unable to enjoy a garden

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Operations

Operational Requirements and Protocols

Veggie PONDS uses the on-orbit VEGGIE facility and requires water from the Potable Water Dispenser (PWD) and use of the Maintenance Work Area (MWA). The Veggie facility is activated with the desired photoperiod, light levels, and fan speed programmed via the control panel. The Veggie Bellows Subassembly is removed from Veggie, and placed on a MWA. PONDS is then placed in the Veggie Bellows Subassembly. The subassembly is reinstalled to the flex arms attached to the Veggie Lightcap. The watering syringe assembly is used to pull PWD water from the water bag and inject it into the PONDS unit.
 
A 10 mL water sample is taken from a PONDS unit and stored in the Minus Eighty Degree Laboratory Freezer for ISS (MELFI) at -95°C. A crew member takes initial photos of the Veggie PONDS experiment setup. The plants are checked regularly, and additional potable water from water bags is added as scheduled using the watering syringe assembly.
 
Three days following initiation, wicks are separated to allow the plants to emerge. Plants are thinned to one plant per pillow after seven days. Scheduled photos of plant growth are taken and downlinked to the ground. The “cut-and-come again” harvest technique is utilized. This is a series of four harvests. More harvests may be scheduled based on the plant growth condition. Some of the harvests are for consumption, and some saved for science.
 
At the final harvest, the leafy green crops are cut at the interface of the PONDS unit and split with half the harvest for consumption and half frozen for science. Science samples are wrapped in foil sheets, placed in a re-sealable bag and stored for sample return in MELFI at -95°C. Video of harvest operations is desirable. Plant samples, and microbial swab samples (-95°C) should be placed in MELFI less than one hour after collection. A second 10 mL water sample is taken from a PONDS unit, and stored in MELFI at -95°C. Excess water is removed from the PONDS unit using the watering syringe assembly to the water bag, and PONDS units are then stored in the sample bag in MELFI at -95°C. PONDS units are returned with other samples for data analysis and hardware refurbishment. Disinfectant ProSan wipes are used to clean and sanitize the interior of the Veggie facility and then discarded.
 
Crew members working with Veggie PONDS respond to questions in the procedure on operations and suggest improvements. Question responses and photographs are sent to the Veggie team via downlink. Science samples, including the data logger, are returned on the first available flight after harvest. Microbial samples, water samples, and plant samples, are returned at -95°C in GLACIER/POLAR. Crew members actively participating in Veggie PONDS operations answer additional questions during the post-increment debrief.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites
The Fairchild Challenge Partners with NASA for Growing Beyond Earth
"Tupperware Takes to Space to Help Improve Astronaut Diets"

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Imagery