Space salads and salty waters

Jul 09, 2023

Bruce Betts•May 31, 2023

We’re pleased to announce the second round of winners of our STEP (Science and Technology Empowered by the Public) grant program. For over 40 years, Planetary Society members and donors have crowdfunded science and technology projects that advance space science and exploration. The STEP grant program continues this tradition by funding innovative projects that are chosen through an open, international, competitive process. The first round of STEP grant winners, chosen in 2022, are already doing fascinating work thanks to The Planetary Society's support.

This year's winners are a project that will compare different methods of growing edible plants in simulated deep-space exploration conditions, and a project that will study salty lakes on Earth that share characteristics with the past and present oceans of other planets and moons.

The future of human exploration of deep space will depend on the sustainable production of fresh crops en route. The 2023 round of STEP grants has awarded $50,000 USD to a team led by Dr. Andrew Palmer of the Florida Institute of Technology to study deep-space agriculture to address this exploration challenge.

Dr. Palmer's team will grow three types of edible plants using two methods: growing the plants in water with added nutrients (a.k.a. hydroponics), and growing them in simulated lunar and Martian dirt (a.k.a. regolith). The project aims to better understand each growing method, and compare their suitability for long-term space travel.

Hydroponics have been used for growing plants in space before, including aboard the International Space Station. But this method faces challenges, especially in the context of long-term use; it requires fertilizers, has a high potential for contamination by fungi and bacteria, and can require a large amount of space.

Regolith is the dirt on the upper surface of a planetary body. It's similar to the soil we have on Earth, but devoid of any microbial life. Using regolith to grow food has its own challenges, such as the high concentration of salts in Martian regolith and the lack of nitrogen on both Mars and the Moon.

Using regolith from a planetary surface could complement hydroponics, but there is a lack of research comparing these methods simultaneously under the same conditions. This STEP grant-funded project will address this knowledge gap.

For this project, called "Evaluation of food production systems for lunar and Martian agriculture," Dr. Palmer's team will grow radish microgreens, lettuce, and tomatoes using hydroponics in one condition, and in regolith in another. The aim of the experiment is to characterize and compare the two methods. The project will use lunar and Martian regolith simulants in their experiments since we don't have regolith from those bodies, other than the limited, precious amounts of lunar regolith returned by past lunar missions.

The team, which includes experts in plant physiology and biochemistry as well as space agriculture and systems efficiency analysis, will test their hypothesis that faster growing crops like microgreens will be better suited for hydroponic systems even in the long term, while slower-growing crops like tomatoes may favor a regolith-based production system.

This project is led by Prof. Andrew Palmer of the Florida Institute of Technology, with co-investigator Prof. Rafael Loureiro from Winston-Salem University, as well as collaborators Prof. J. Travis Hunsucker, Florida Institute of Technology; Dr. Laura E. Fackrell, NASA Postdoctoral Fellow, Jet Propulsion Laboratory; Thiara Bento, Florida Institute of Technology; and Jéssica Carneiro Oliveira, Universidade Federal do Estado do Rio de Janeiro, Brazil.

Although nowhere on Earth is identical to another planet or moon's environment, there are places where conditions are analogous — similar enough in certain respects to be worth studying. Scientists study planetary analogues to learn more about what is possible in the conditions we think exist on other worlds. The second winner of a 2023 STEP grant is a team led by Dr. Jacob Buffo of Dartmouth College, who were awarded $49,284 USD for their project to study small, extremely salty lakes in British Columbia, Canada, that may be analogous to ancient Mars as well as some of the Solar System's ocean moons, places of key interest in the search for life.

Liquid water is one of the very few things required by all life on Earth, and so worlds such as Mars, Europa, and Enceladus that have evidence of past or present liquid water are important in the search for life beyond our planet. The water on these worlds is often salty, which allows it to remain liquid at colder temperatures. Studying salty water environments on Earth can give us insights into what these alien environments may be like, including whether they could be habitable.

Not every saltwater body on Earth is analogous to salty alien waters, though. The salt in Earth's oceans is mostly table salt (NaCl), which is not as prevalent in the salts found on Mars and in the subsurface oceans of Europa and Enceladus. Dr. Buffo's project would study lakes containing sodium carbonate (Na2CO3), sodium sulfate (Na2SO4), and magnesium sulfate (MgSO4), which more closely mirror the compositions of these alien oceans.

This project, called "Multiscale Characterization of Brine-Rich Planetary Analog Environments," will study several hypersaline lakes in British Columbia, Canada, using a wide variety of data collected at different scales and distances: from spacecraft to drones to in-person sampling. This will allow the team to not only learn about these analogues to exotic planetary locations, but also learn about efficient ways to use remote-sensing data (data taken from a distance) to choose locations that are the most interesting to be studied in greater detail up close. This is similar to what is typically done in planetary exploration, going from orbital data to landers and rovers on the surface.

In year one, they will carry out field investigations to create multiscale (physical, spectral, thermal, electromagnetic, and biogeochemical) profiles of the ice-brine-sediment systems of five distinct lake systems in British Columbia's Cariboo Plateau. In year two, they’ll use what they have learned to predict what they will find at two additional unexplored lakes, carrying out a simulated planetary mission to evaluate their methodology and their science. The team will create a database from their data that will be accessible to other scientists and the public.

The team is very diverse, including specializations in remote sensing, geochemistry, astrobiology, planetary analog systems, biogeochemistry, geobiology, planetary science, and geophysics. Principal Investigator Dr. Jacob Buffo of Dartmouth College is joined by a number of co-investigators at a variety of institutions, each bringing their own expertise and often instrumentation to the project: Dr. Alexandra Pontefract at Georgetown University; Prof. Magdalena Osburn and graduate student Floyd Nichols at Northwestern University; Dr. Mitchell Barklage of the Illinois State Geological Survey and Northwestern University; graduate student Emma Brown at Arizona State University; and graduate student Emmy B. Hughes at the Georgia Institute of Technology.

We are grateful to the Halıcıoğlu Family Foundation for its generous support of the development and implementation of the STEP grants program. We also thank all of our members who have been crowdfunding our science and technology projects since long before the term crowdfunding was invented. Thank you to the members of our Board of Directors who participated in the review process of proposals. And thank you to everyone who proposed. There were far more worthy proposals than what we were able to fund during this round.

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