Growing and Eating Lettuce in Space

Journeying outside of low-earth orbit and setting up long-term or permanent colonies on other planets or moons is fraught with challenges. One obvious challenge is food production. Regular deliveries from Earth are costly and risky, and freshness isn’t always an option. So, perhaps food can be grown on site? NASA is currently exploring this question by carrying out a series of experiments using an aptly named piece of hardware called Veggie, which was delivered and installed on the International Space Station in the spring of 2014. Experiments began shortly thereafter, and last month NASA astronauts finally got to taste the leaves of their labor for the first time.

Veggie is a plant growth chamber that was developed by Orbital Technologies Corporation. It provides environmental conditions – such as light, temperature, and airflow – that are suitable for plant growth. Accompanying the delivery of Veggie were three sets of planting pillows – specially designed pouches that contain growing media, fertilizer, and seeds. The pillows are placed on rooting mats inside Veggie and watered using a wicking system . Light is delivered by red, blue, and green LEDs. The red and blue wavelengths are necessary for plant growth, and the green wavelength helps the plants look more appealing to the astronauts.

Veggie: an expandable plant growth facility designed for the International Space Station - photo credit: NASA/Bryan Onate

Veggie: an expandable plant growth facility designed for growing plants on the International Space Station – photo credit: NASA/Bryan Onate

Two sets of pillows were seeded with a variety of red romaine lettuce called ‘Outredgeous.’ This particular plant was chosen because it is easy to grow, tastes good, and has high nutritional value. The first lettuce harvest was sent back to earth last October for a food safety analysis. Once it was deemed free of harmful bacteria and safe to eat, the astronauts were cleared to start the second round of red romaine, which they did in early July 2015. The third set of planting pillows contain zinnia seeds, and according to statements made by astronaut Scott Kelly on Twitter, it doesn’t sound like those have been grown yet.

After caring for the second round of lettuce plants for 33 days, it was finally time to taste them. The astronauts first cleaned each leaf with citric acid based sanitizing wipes and then sampled the leaves plain. Next they tried them with a little olive oil and balsamic vinegar. They shared their experience in real time via Twitter, which is documented in this New York Times article. They saved a few leaves for their Russian friends who were out on a spacewalk, and then packaged the rest up to be frozen and sent back to Earth for analysis.

Outredgeous Territorial Seed Company

Lactuca sativa ‘Outredgeous’ – the variety of red romaine lettuce grown and eaten by NASA astronauts on the International Space Station (photo credit: Territorial Seed Company)

This isn’t the first time plants have been grown and eaten in space. Russian cosmonauts grew and consumed mizuna (Japanese mustard) back in 2002 using a plant growth chamber developed in collaboration with a lab at Utah State University. They have also used the growth chamber to grow peas, radishes, and other plants. Read more about these experiments here.

Growing plants in space, apart from providing fresh food, offers psychological benefits. In an otherwise sterile and metallic environment, having something green (or red, in the case of the lettuce) to look at and care for has the potential to lift the moods of crew members aboard the space station. NASA scientist, Dr. Gioia Massa, who is overseeing the project sums it up nicely, “The farther and longer humans go away from Earth, the greater the need to grow plants for food, atmosphere recycling, and psychological benefits. I think that plant systems will become important components of any long-duration exploration scenario.”

Want to learn more? Read about the project here, here, and here. Also watch this video about growing plants in space.

 

Just for fun, there is a great children’s fiction book involving plants in space called June 29, 1999 by David Wiesner which is definitely worth a look.

More “Plants in Space” Posts on Awkward Botany:

Growing Plants on the Moon

Growing Plants in Outer Space

Growing Plants in Outer Space

Last December I wrote about a mission to the moon that will involve growing plants to determine how they will perform in a lunar environment. That mission is still at least a year away. In the meantime, research involving plant growth in space continues onboard the International Space Station (ISS). Numerous experiments have been carried out so far with the general aim of observing the effects of microgravity and other extraterrestrial environmental factors on plant growth. The larger aim, of course, is to develop methods for growing food in space in order to feed future space travelers as they colonize other celestial bodies, such as the Moon and Mars. Providing oxygen and contributing to psychological well-being are additional benefits of growing plants in space.

International Space Station (photo credit: wikimedia commons)

International Space Station (photo credit: wikimedia commons)

Several weeks ago a spacecraft returned to Earth from ISS carrying samples and data from a variety of studies, including a plant study being carried out by the University of Wisconsin-Madison’s Department of Botany. The study consisted of three groups of Arabidopsis thaliana – a wild type group, a group with a gene involved in gravity sensing always turned on, and a group with that same gene always turned off. The plants were grown from seed on petri dishes, and the seedlings (totaling 1000 plants) were returned to Earth after a few weeks of growth. The petri dishes were placed in deep freeze upon returning to Madison. Eventually, RNA will be extracted from each of the plants and analyzed.

Arabidopsis thaliana is a plant in the mustard family (Brassicaceae) that is commonly used in biological studies because it is fast growing with a short life cycle – it germinates, flowers, and produces seed in about 6 weeks  – and it has a relatively small genome that has been completely mapped. This makes it ideal for studies like this one that aim to observe genes involved in responding to particular environmental factors – in this case microgravity.

Arabidopsis thaliana (photo credit: www.eol.org)

Arabidopsis thaliana (photo credit: www.eol.org)

Plants grown in the weightlessness of space get long, spindly, and weak. Plants grown on Earth in a protected environment without mechanical stresses like wind or rain are more susceptible to pests and diseases compared to those that are subject to such disturbances. It turns out that there is a gene that codes for a protein that senses gravity, and this same protein senses other mechanical stresses as well. This means that studies that help advance the science of growing plants in space could also help improve crop plants here on Earth.

The RNA extracted from the Arabidobsis plants recently returned from space will not only aid in the research being done at UW-Madison, but will also become part of a much larger body of research through NASA’s GeneLab. Access to space is limited, so GeneLab makes available the data recovered from studies like this one to anyone interested in doing studies of their own. The GeneLab will also make it possible to compare the Arabidopsis groups in this study to several other Arabidopsis ecotypes, which will aid in determining plants best suited for microgravity environments.

Read more about this study at NASA, Science Daily, and Plants in Microgravity (a blog produced by Simon Gilroy’s Lab, Department of Botany, UW-Madison). Also, “plants in space” has a Wikipedia page