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NASA is researching how to grow plants in space efficiently and how to use plants to sustain humans. NASA needs to provide safe, nutritious and palatable food to astronauts, particularly for long-duration space missions. Plants can also help to provide a breathable atmosphere (by taking in carbon dioxide and releasing oxygen) and to produce pure water (via transpiration). And we know that plants can have psychological benefits, especially for astronauts in extreme environments.
The ‘Veggie’ vegetable production system is a platform for researching the growth of horticultural plant species under LED lighting. It was designed to be small and lightweight, to be energy efficient, and to require minimal intervention from the crew. The goal of the researchers behind the Veggie project is to provide fresh ‘pick and eat’ crops for the ISS astronauts.
Plants in Veggie usually grow in plant ‘pillows’, small grow bags filled with a growing medium and controlled release fertilisers. Until 2020, all seeds were fixed into the plant pillows on Earth before being sent to the ISS.
They start into growth when they are loaded into Veggie by an astronaut, and watered. VEG-03 J will trial the use of soluble seed films that can be ‘planted’ by the astronauts. NASA is also experimenting with an alternative to the pillows called PONDS (see below), which have a greater capacity and would allow the growth of larger plants.
The first Veggie unit was launched to the International Space Station (ISS) on 18 April 2014 on flight CRS-3. In August 2015, Scott Kelly, Kjell Lindgren and Kimiya Yui ate some of the ‘Outredgeous’ red romaine lettuce that had been growing in space for 33 days. Later that year, Veggie was reloaded with Zinnias, which bloomed in time for Valentine’s Day 2016.
A second unit was launched on 18 April 2017 on flight OA-7. The two units were used together for the first time in February 2018, with experiments VEG03 E&F running concurrently.
A variety of salad crops have now been grown in Veggie and eaten by the crew. Veggie is being used to trial different growing media and fertilisers, different lighting combinations, and different cropping methods, to see what works best in orbit. Researchers also use the Veggie system for more general plant-based research.
List of Veggie Crop Experiments for Human Consumption
- VEG-01 B: ‘Outredgeous’ red romaine lettuce – July 8, 2015 – August 10, 2015.
- VEG-03 A: ‘Outredgeous’ red romaine lettuce using cut-and-come-again repetitive harvest technique – October 25, 2016 – December 28, 2016.
- VEG-03 B: ‘Tokyo Bekana’ Chinese cabbage – January 20, 2017 – February 17, 2017.
- VEG-03 C: ‘Tokyo Bekana’ Chinese cabbage using cut-and-come-again repetitive harvest technique – April 3, 2017 – May 31, 2017.
- VEG-03 D: Mizuna Mustard, ‘Outredgeous’ red romaine lettuce, and ‘Waldmann’s Green’ lettuce using cut-and-come-again repetitive harvest technique – September 26, 2017 – November 23, 2017 (harvested and eaten on Thanksgiving).
- VEG-03 E: Mizuna Mustard, ‘Outredgeous’ red romaine lettuce, and ‘Waldmann’s Green’ lettuce using cut-and-come-again repetitive harvest technique grown concurrent with Veg03 F – February 6, 2018 – April 6, 2018.
- VEG-03 F: Mizuna Mustard, ‘Outredgeous’ red romaine lettuce, and ‘Waldmann’s Green’ lettuce using cut-and-come-again repetitive harvest technique grown concurrent with Veg03 E – February 9, 2018 – April 9, 2018.
- VEG-03 G: ‘Red Russian’ kale and ‘Dragoon’ lettuce – October 25, 2018 – November 28, 2018.
- VEG-03 H: ‘Wasabi’ Mustard and ‘Extra Dwarf’ Pak Choi – March 9, 2019 – April 6, 2019.
- VEG-04 A: Mizuna Mustard using Red-Rich and Blue-Rich light recipes – June 4, 2019 – July 9, 2019.
- VEG-04 B: Mizuna Mustard grown using Red-Rich and Blue-Rich light recipes and cut-and-come-again repetitive harvest technique – experiment initiated on October 1st.
List of Veggie Crop Experiments Not for Human Consumption
- VEG-01 A: ‘Outredgeous’ red romaine lettuce – May 8, 2014 – June 10, 2014 (proof-of-concept experiment).
- APEX-03-1: Arabidopsis – January 15, 2015 – January 26, 2015.
- APEX-03-2: Arabidopsis – January 15, 2015 – February 3, 2015.
- VEG-01 C: Zinnia – November 16, 2016 – February 14, 2016.
- CERES: Lentil, Mustard, and Radish – January 3, 2017 – January 12, 2017 (European SpaceAgency’s education program experiment that grew the same seeds as hundreds of school children on Earth)
- APEX-04: Arabidopsis – February 25, 2017 – March 16, 2017.
- APEX-05: Arabidopsis – December 20, 2017 – January 9, 2018.
- APEX-06: Brachypodium – April 12, 2018 – April 20, 2018.
- VEG-PONDS-01: ‘Outredgeous’ red romaine lettuce – April 25, 2018 – May 14, 2018 (tech demo of a new type of container the Passive Orbital Nutrient Deliver System).
- Space Algae: Algae.
- Microalgae: Algae.
- VEG-PONDS-02: ‘Outredgeous’ red romaine lettuce – April 25, 2019 – May 17, 2019 (second tech demo for PONDS).
Read blog posts about Veggie.
In the original Veggie series of experiments, plants are grown in seed bags called ‘pillows’ that astronauts water using a syringe. They’ve worked really well for quick salad crops. Still, larger leafy vegetables and fruiting vegetables such as tomatoes needed new hardware.
At the NASA Kennedy Space Center, scientists began exploring new solutions that would support larger plants and reduce the frequency with which astronauts had to water. They came up with a semi-hydroponic design called the Passive Orbital Nutrient Delivery System (PONDS).
Tupperware Brands and Techshot Inc. developed the PONDS units. They have a higher water capacity and more space for root growth and are designed to alleviate the problems with water distribution in microgravity. They’re also entirely passive, providing air and water to roots without using extra power.
In PONDS, plants are grown in a clay medium called arcillite. It uses a mixture of two different particle sizes, and part of the experiment will be to determine the most efficient particle size mix. With a water reservoir that holds 400 ml, PONDS means astronauts only have to water small plants once a week. For larger plants, the water will last a couple of days.
Each Veggie unit (there are currently two in operation) can hold up to six PONDS at a time. The standard Veggie pillows are still in use, providing crops that the ISS crew can harvest and eat. A series of VEG-PONDS experiments are testing and improving on the new hardware, with the plants returned to Earth for analysis. The main aim of VEG-PONDS is to investigate whether improved water and nutrient delivery can produce more uniform plant growth. This will be important for crops with more stringent water demands.
The first seven PONDS modules launched to the ISS on CRS-14 in April 2018. They were used to grow red romaine lettuce (‘Outredgeous’) from
25 April to 14 May 2018. This lettuce has been grown several times in Veggie pillows, so data can be compared.
Four of the PONDS were black “opaque” modules, while two were “shrouded” modules with a clear window and a removable cover to allow astronauts to observe root growth. The final module was transparent and did not contain a plant. It was used to observe how water moved around the reservoir in space.
The results from VEG-PONDS-01 led to some improvements in the design, which were tested in a second experiment. VEG-PONDS-02 launched to the ISS on BG-11, in April 2019. This investigation grew the same Outredgeous lettuce, from 25 April to 17 May 2019.
VEG-PONDS-02 tested three new PONDS design, with four of each kind. With 12 PONDS in total, it filled both Veggie systems. This time, six of the modules were clear to allow astronauts to observe the water flow.
A third VEG-PONDS experiment is now scheduled to launch on CRS-20 on or after 6 March 2020. The experiment will use both Veggie systems and the Outregdeous lettuce and is expected to last 21 days. This time, the crew will be able to eat some of their harvest.
The various design modifications being tested in VEG-PONDS-3 include using different types of wicks to hold the plant seeds in place and using blocks of oasis foam to draw excess water away from sprouting seeds.
“PONDS has kind of become the story of Goldilocks. The first time we tested in microgravity, too much water was delivered to the seeds. The second time, too little water. And the third time we hope is going to be just right. We’re in the fine-tuning phase now, and we’re excited to see this all come to fruition.”Dave Reed, Florida operations director for Techshot
Both Veggie and Veggie PONDS contribute to basic research on plant cultivation and will benefit agriculture and horticulture on Earth. The technology could be adapted for use in areas where there is little room for growing plants, and for people who would otherwise be unable to enjoy a garden.
Massa, Gioia D., et al. “VEG-01: Veggie hardware validation testing on the International Space Station.” Open Agriculture 2.1 (2017): 33-41.
Massa, Gioia D., et al. “Growth chambers on the International Space Station for large plants.” VIII International Symposium on Light in Horticulture 1134. 2016.