Future of farming? How astronauts are growing food in space

Following his successful mission to the International Space Station (ISS), making him only the second Indian in space, Group Captain Shubhanshu Shukla is back on Earth and has returned to India. On Monday evening, the Indian astronaut met with Prime Minister Narendra Modi at the latter’s residence, 7 Lok Kalyan Marg, discussing the success of the Axiom-4 mission, as well as India’s ambitious Gaganyaan mission.

During the interaction, Shukla spoke about his many experiments aboard the ISS, including growing crops in space. For those who aren’t aware, Shukla turned farmer in space — growing ‘moong’ and ‘methi’ seeds in petri dishes aboard the ISS. Speaking on the same to Modi, Shukla said that food remains a major challenge aboard space stations due to limited space and expensive cargo. He further noted the potential of his experiments to address food security challenges — not only for astronauts but also for vulnerable populations on Earth.

This got us wondering — how do plants grow in space? And why is it important for space travel?

Shukla turns space farmer

As part of his now successful Axiom-4 mission, Shukla conducted various experiments in space, including growing plants on board the ISS. In fact, this was the most crucial of his seven experiments.

As part of the mission, he planted moong and methi seeds in petri dishes and  kept them in a storage freezer. This activity was part of a study into the influence of microgravity on germination and early plant development. These seeds will be cultivated over multiple generations after their return to earth, with researchers looking into changes in their genetics, microbial ecosystems and nutritional profiles.

Recalling this experiment, he told PM Modi in Monday’s discussion, “Food is a big challenge on space station. Many experiments are ongoing to grow food in space. We did micro-gravity research — it could solve food security problems on earth too.”

Growing food in space

But Shukla isn’t the first astronaut to try his hand at farming on board the ISS. Astronauts have been growing plants in space on a fairly small scale. In fact, in 2014, Nasa, America’s space agency, launched the Vegetable Production System, known as Veggie, on board the ISS. Simply put, it is a space garden, which is the size of an average carry-on bag. It typically holds six plants.

The purpose of Veggie 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.

To date, Veggie has successfully grown a variety of plants, including three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale and zinnia flowers. So far, some of the plants have been harvested and eaten by the crew members, while remaining samples have returned to earth to be analyeed. One concern was harmful microbes growing on the produce. So far, no harmful contamination has been detected, and the food has been safe (and enjoyable) for the crew to eat.

But how are these plants grown?

There are two ways: one is through hydroponics — the method of growing plants without soil, using nutrient-rich water solutions — and the second being through aeroponics, which eliminates the need for soil or any other medium. Plants can also be grown in space in soil-like media.

In Nasa’s Veggie garden, the plants are grown 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.

Earlier, this year, even Isro made strides in space farming with the CROPS box, which is like a mini-greenhouse. It is an experimental module designed to develop Isro’s capabilities for growing and sustaining plants in space. It has a soil-like medium, water, sunlight-mimicking lights, and Earth-like air.

Challenges in growing food in space

However, growing plants in space is no child’s play and goes beyond just having a green thumb.

Firstly, astronauts have to contend with microgravity . In a zero-gravity environment, plants struggle to orient themselves properly, as their natural response to gravity doesn’t function the same way. Essentially, the plant doesn’t have the same instinct for the roots to grow downwards and the stems to grow upwards, which can affect development and nutrient absorption.

There’s also the issue of having less space and no natural light. On earth, plants have access to loads of natural sunlight. However, this doesn’t apply to space. For this reason, artificial light has to be provided, but that too is difficult owing to the importance attached to using energy efficiently. Energy can’t be wasted on light bulbs.

In addition, different types of lighting create different levels of heat, and extra heat is something spacecraft must eliminate. Additionally, astronauts don’t have extra room to lug spare light bulbs through space, so they need a lighting source with staying power, like light emitting diodes (LEDs). The confined quarters of the ISS is another challenge that astronauts have to deal with.

Besides these challenges, there’s also the problem of radiation and contamination. There’s a chance that the plants grown in space be contaminated with organisms from space, making them inedible for humans. Changes in their genetic codes could be harmful in other ways. As How Stuff Works notes, we could land up with a space version of kudzu — an invasive species of plant brought to the US from Japan in the late 1800s.

Importance of space farming

But what purpose does growing plants in space serve?

The main benefit of growing plants in space is to enable long-term space exploration — we are eyeing longer space missions and even colonising Mars . For this, it is critical that astronauts have a regenerative source of food. After all, imagine going on vacation for a year and having to pack all the meals you planned on eating — your bags would only be stuffed with groceries.

Plants could also assist the life support system in other ways too. They can be used to purify water and recycle carbon dioxide into oxygen. If grown on a large-enough scale, plants could hugely impact how spacecraft and colonies are designed.

As Siddharth Pandey, an affiliate research scientist with US-based Blue Marble Space Institute of Science, told The Indian Express, “Since plants release oxygen during photosynthesis, growing them in space can help keep the air aboard spacecraft breathable. Plants can recycle carbon dioxide and organic waste, creating a closed-loop life support system.”

Space farming can also benefit humans on Earth. Scientists hope to transfer the knowledge they gain from growing plants in the inhospitable climate of space to hostile climates on earth. This will help as land becomes scarcer and less fertile.

It seems that while we are far, far away from a salad bar in space, we are making giant leaps in space farming.

With inputs from agencies