Student Emily Aguesse helps clear a hole to plant a small giant sequoia tree from NASA's Artemis I Mission's tree seeds, which travelled around the moon twice, in Lake Forest, Calif., in October, 2024.Damian Dovarganes/The Associated Press
Aaron Boley is the co-author of Who Owns Outer Space: International Law, Astrophysics, and the Sustainable Development of Space. He is a professor of astrophysics at the University of British Columbia.
There are trees that have been to the moon.
In 1971, smokejumper-turned-astronaut Stuart Roosa piloted the Apollo 14 command module on its lunar voyage, carrying hundreds of seeds from five different tree species. The question was, in part, whether the seeds could survive travel into deep space and germinate once returned to Earth. More than 400 sprouted.
“Moon trees” can be found throughout the United States, with a limited number in Switzerland, Brazil and Japan. Unfortunately, the locations of many of these giant space travellers have been lost with time.
Crewed space exploration has long experimented with seeds and animals. Kosmos 110 in 1966 launched the dogs Veterok and Ugolyok into orbit about Earth, remaining there for 22 days before returning alive. The dogs were not alone. The spacecraft carried seeds that germinated while in orbit, growing lettuce and cabbage.
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Since then, special habitats have helped scientists study plants in space, where the lack of a clear “up” and “down” complicates their growth. Environmental cues, such as light, can help plants orient themselves, yet not all plants thrive.
Beans, oats and pine seedlings were grown during Space Shuttle flights, while kale, cabbage, lettuce, mustard and zinnias have filled “gardens” on the International Space Station. Recently, China’s Chang’e-4 mission sprouted seeds in a controlled environment on the lunar surface, although the plants died soon after owing to large temperature swings in the habitat.
Knowing which plants grow well in space could help sustain astronauts on long missions. Plants are also useful in understanding spaceflight’s toll on life. Similar to how astronauts experience adverse health effects from prolonged periods of “weightlessness,” such as bone-density loss, plants can see a reduction of lignin, an important component in their cellular structure.
In November, 2022, the Artemis I mission launched the Orion capsule into deep space, where it orbited the moon and returned to Earth. Onboard was a Canadian astrobiology experiment, exposing yeast to the harsh radiation conditions of deep space. Other experiments investigated DNA repair in fungi, gene expression in algae, and whether space seeds grow plants with altered nutritional values. And tucked away in these experiments was another generation of moon tree seeds.
The Canadian Space Agency is a partner in the NASA-led Artemis program. In 2026, Jeremy Hansen is slated to fly on Artemis II and become the first Canadian (and the first non-American) to orbit the moon. He should also take some seeds.
Artemis II mission specialist Jeremy Hansen stands in front of the crew transport vehicle during a countdown demonstration test in Cape Canaveral, Fla., on Dec. 20.Phelan M. Ebenhack/The Associated Press
Space exploration is a humbling endeavour, whether through crewed spaceflight, robots or astronomical observations. It is a reminder that we live on a speck of rock in a vast cosmos full of objects and processes that are awe-inspiring, terrifying, familiar and alien.
Four-and-a-half billion years ago the moon was born when a rapidly spinning and hellish Earth was struck by a Mars-sized object in a glancing collision. Since then, the Earth and moon have evolved together. Gravity between the two causes tides, forming critical ecological zones on Earth. The moon’s gravitational influence helps to stabilize our climate by minimizing variations in the Earth’s axial tilt over long timescales.
Exploring and studying the moon is of scientific interest on its own, but doing so can give unique insight into the solar system and the events that eventually gave rise to life on Earth.
There is a danger in lunar exploration, though, if it becomes driven by competition for resources and suspicion between actors. Indeed, protecting “celestial lines of commerce” is already being used by some to justify militarizing cislunar space: the volume of space between Earth and the moon, and related orbits.
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Fortunately, there are international efforts to build trust among space actors. Here, Canada can play an important role, striving to foster co-operation and taking steps to avoid colonial and destructive practices that would not just harm humanity’s exploration of the solar system, but could come with serious consequences on Earth.
Taking seeds to the moon will not solve such issues by itself. Nor is it likely to lead to a major scientific breakthrough. But it is a powerful symbol.
When someone plants a tree, it is an intergenerational act. Rooted to the Earth yet reaching to the sky, moon trees can remind us of commitments to each other, as well as to the Earth and moon. A diverse selection of trees, spread throughout Canada and fostered by its many peoples, would form part of a living history and a growing hope that as Canada and humanity ventures beyond Earth, we do so in peace.
I hope Jeremy has some extra room in his pockets.