Space lettuce: NASA's plans to grow nutritious plants on Mars

NASA is examining ways to ensure explorers have nourishing produce, including fresh plants, on future space missions to the Moon and Mars. While sealed food packets get the job done, they can lose flavor and vitamins over time.

Cultivating leafy greens and vegetables on the space station could address this problem and give crews a happier mental state.

Efforts to grow plants such as lettuce, peppers, radishes, and tomatoes in microgravity have been underway, revealing new insights into how spaceflight influences plant genetics, water use, and flavor.

Plants are key to space exploration

This work is being guided by Gioia Massa from NASA. Her background involves studying plant behavior in space to help boost the variety and taste of fresh crops. 

As NASA paves the path toward deeper space travel, her team has focused on how microgravity and factors like humidity and light control affect plant shape, nutrient quality, and yield.

By examining bacteria that live alongside the plants, they also track whether these microorganisms remain safe and beneficial for human health.

Growing crops in microgravity

One key study, Plant Habitat-07, looks at how lettuce tolerates different moisture conditions in microgravity.

Although water is crucial for plant cells, too much can restrict oxygen at the roots, and too little can cause wilting. 

This investigation uses four moisture scenarios in a specialized growth chamber to see how plants adjust nutrient production.

Researchers check yield, overall plant health, and whether bacterial populations on the leaves pose any risk. Early data point to the importance of balancing water to maintain robust leaves that still taste good.

Making space-grown veggies tastier

NASA’s Veg-04A and Veg-04B explorations spotlighted how light quality and fertilizer affect lettuce and leafy greens on station.

Studies found that switching red and blue LEDs, or adjusting nutrient formulas, changes how the leaves look, taste, and grow. 

These investigations guided more recent plantings of other crops, such as tomatoes. Crew members gave feedback on freshness and flavor, which could inform future seed selection for diverse salads during long-duration spaceflights.

A study on Arabidopsis thaliana (thale cress) showed that low gravity changes gene expression and how plants regulate key chemical markers. Researchers tracked DNA methylation—a process that can switch genes on or off.

Their discoveries open new avenues for customizing plant genes to handle the difficulties of space, like unusual water movement or limited floor space.

Hormones and movement

Scientists have explored how plant hormones guide growth in microgravity. One series of tests examined auxins, natural signals that steer root and shoot direction. 

Some plant species had lower auxin levels when floating in microgravity, which curbed their normal pattern of upward stem development.

Others had higher levels, suggesting that the exact outcome varies by species. This subtle shift in plant chemistry helps NASA design growth chambers that best support each crop’s needs.

Engineering plants to handle space

Roots and shoots in microgravity can develop weaker supportive tissues or, in some cases, produce thicker walls for unknown reasons.

An investigation used a suite of lab tools to identify changes in molecules that build plant cell walls, especially those providing mechanical strength. 

Although some species quickly adapt and form healthy walls, others remain frail. NASA’s next step is to refine which varieties flourish with minimal gravity or to tweak conditions so roots are less prone to bending or thinning.

Sterols and space-based flowering

Researchers on the Resist Tubule mission uncovered that arabidopsis plants grown in microgravity sometimes see reduced sterol levels. 

Sterols help keep cell membranes stable and support a range of growth responses, including when and how a plant transitions to flowering.

The drop in sterols in microgravity can slow certain steps in development. By noting which genes control those sterols, scientists may spot ways to keep plants on schedule.

Preparing for space missions with plants

Having tasty salad greens aboard the station is only the first step. NASA’s focus is on sustaining crews through missions lasting many months.

The progress so far is encouraging: fresh produce is feasible in orbit, and each new finding helps refine the process. 

As more crops are tested for flavor, nutrition, and shelf life, humans gain the ability to grow food far from our planet.

With input from experts like Gioia Massa, the future of in-space agriculture looks promising for both nourishment and crew satisfaction.

The study is published in the Journal of Plant Interactions.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–