Explained | Growing vegetables in space is a big deal, and the lost tomatoes are proof

Space is amazing with numerous things still undiscovered. Recently, the National Aeronautics and Space Administration (NASA) shared footage of two tomatoes that were lost in space last year after they were harvested on the International Space Station (ISS). "Despite being nearly a year after the initial disappearance of the tomatoes, the fruit was found in a plastic bag dehydrated and slightly squished," NASA officials wrote in an update on Dec 14.

The officials added that other than some discolouration, the tomatoes had no visible microbial or fungal growth. As astronauts are constantly exploring space, an important aspect is how well are they fed.

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For years, astronauts have received regular shipments of a wide variety of freeze-dried and prepackaged meals to cover their dietary needs. However, when astronauts venture further into space for months or even years, the vitamins in prepackaged form break down over time, which will affect their health, according to NASA. And in such cases, the provision of fresh fruits and vegetables becomes crucial.

What is Veggie?

According to NASA's website, the Vegetable Production System, also known as Veggie, is a space garden residing on the ISS. "Veggie’s purpose is to help NASA study plant growth in microgravity while adding fresh food to the astronauts’ diet and enhancing happiness and well-being on the orbiting laboratory," the space agency said.

The garden made by the project is about the size of a carry-on piece of luggage and typically holds six plants. Each plant grows in a “pillow” filled with a clay-based growth media and fertiliser.

"The pillows are important to help distribute water, nutrients and air in a healthy balance around the roots. Otherwise, the roots would either drown in water or be engulfed by air because of the way fluids in space tend to form bubbles," as per NASA.

Now due to the absence of gravity in space, plants depend on other environmental factors such as light, to orient and guide growth. Inside the space station, LEDs placed above the plants produce a spectrum of light suited for the plants’ growth. "Since plants reflect a lot of green light and use more red and blue wavelengths, the Veggie chamber typically glows magenta pink," the website said.

How successful has Veggie been?

NASA said that to date, the Veggie project has grown a variety of plants, including three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale, and zinnia flowers. Some of these plants were harvested and eaten by the crew members, with the remaining samples returned to Earth to be analysed.

NASA highlighted that one particular concern was harmful microbes growing on the produce. However, no harmful contamination has been detected so far.

The space agency envisions planting more produce in the future, such as tomatoes and peppers. "Foods like berries, certain beans, and other antioxidant-rich foods would have the added benefit of providing some space radiation protection for crew members who eat them," it said.

Just like Veggie, there is another growth chamber on the ISS for plant research. The chamber, called the Advanced Plant Habitat (APH), uses LED lights and a porous clay substrate with controlled-release fertiliser to deliver water, nutrients, and oxygen to the plant roots.

But unlike Veggie, it is enclosed and automated with cameras and more than 180 sensors that are in constant interactive contact with a team on the ground at the Kennedy Space Center.

When a harvest is ready for research, the crew aboard the ISS collects samples from the plants and sends them back to Earth to be studied so scientists can better understand how space affected their growth and development.

Cultivating peppers in space

NASA further said that its Plant Habitat-04 (PH-04) experiment cultivated Hatch Chile peppers aboard the ISS. As per the experiment, the astronauts would eat some of the peppers and send the rest back to Earth for analysis.

This plant experiment will be one of the most complex to date on the station because of the long germination and growing times, according to the space agency.

The Hatch Chile pepper is considered a mild heat pepper, with a rating of 2,000-4,000 Scoville Heat Units. The rating can vary based on growing methods and environmental conditions.

Now why should peppers be cultivated in space? NASA has said that peppers contain several key nutrients and are an excellent source of vitamin C. The plants are also robust with a good chance of growing successfully in microgravity.

"They are easy to handle in microgravity and are a pick-and-eat crop that does not require cooking or complex processing. The fruit also has low microbial levels, so they are safe for astronauts to consume," NASA added.

Chinagrowing vegetables aboard Tiangong space station

China is also preparing itself for deep-space exploration by growing vegetables aboard theTiangong space station.Shenzhou 16 astronauts, mission commander Jing Haipeng and rookiesZhu Yangzhu and Gui Haichao cultivatedveggies using two sets of specialised equipment. Four batches of lettuce have already been produced, while under thesecond operation,cherry tomatoes and green onions are being grown.