Page 175 - International Space Station Benefits for Humanity, 3rd edition.

from ground-control experiments. When the space- and oxygen. When properly wetted, as water is used
produced seeds were planted on the ground, plants by the roots, surface tension pulls additional liquid along
that grew were no different from the control sample. without filling the pore spaces, and therefore without
The completed work has great applied value because, preventing oxygen from diffusing through the open
in the process of creating and operating the space spaces to the roots. Studies in the Lada greenhouse
greenhouse, cutting-edge equipment and software have addressed the importance of root zone media
were developed, thereby making it possible to grow in these extreme artificial conditions. Scientists have
plants automatically. The psycho-physiological aspect studied a variety of root zone substrates—growth
of the interaction between humans and plants in a media, material particle sizes and packing structure—
habitable pressurized volume was studied, and data and learned which combinations work best.
were obtained on the safety of cultivating plant Knowledge of root zone substrates has allowed
biomass on a space station for human consumption. scientists to improve their predictions of how artificial
These data are of great interest for design work soils will behave when they are irrigated—in space and
to create productive greenhouses that are part of on Earth—and to design specific plant growth media
promising life support systems of any living complexes and artificial soils for greenhouses and other large-
that are cut off from the Earth’s biosphere. scale plant production facilities on Earth. Models that
Scientists have also studied the interaction of plants describe the behavior of water and oxygen learned
with the soil. The processes by which plant roots from these space experiments have been published
receive water, gases and nutrients are different in space in scientific journals, thereby allowing commercial
than they are on Earth. On Earth, gravity and surface users to access the information without divulging their
tension combine to move water through soil, thus propriety growth media mixtures. Sensor technology
allowing air to move through the pore spaces in the soil developed to monitor the Lada root zone is being
to the plant’s roots. In space, soil is replaced with an applied to monitor soil properties in a state-of-the-art
artificial growth medium that is made up of small grains measurement facility at an experimental forest.
or other porous material. In microgravity, liquid moves Colleagues from many Russian and non-Russian
through capillary action, where the liquid is attracted organizations participated in carrying out work
to the adjacent surface of a solid material. The surface according to the Rasteniya program in the Lada
tension of the liquid pulls additional liquid along as
each new surface is wetted. If the plant is overwatered
and all of the surface area and open spaces within
the growth medium are filled with liquid, then gas (air)
cannot move, and the plant’s roots are deprived of air

Cosmonaut Maxim Suraev, Expedition 22 flight
Cosmonaut Sergey Volkov (onboard engineer engineer, holds Mizun lettuce plants from the
Expeditions 28/29) studies super dwarf wheat BIO-5 Rasteniya-2 (Plants-2) experiment in
as part of the Rasenyia-2 investigation. the Service Module during Expedition 20.
Image credit: NASA Image credit: NASA

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