ROOM
49
Astronautics
First attempts
By the time the spaceflight era really got under
way there was already a clear understanding of
the potential role of plants in space exploration.
But unlike Tsiolkovsky, modern scientists had
doubts that plants would be able to successfully
grow and reproduce in a zero gravity because their
dependence on gravity was considered too great.
Early experiments also suggested it was unlikely
that plants would thrive in space. From 1971 to 1990
plants in space were cultivated in small greenhouses,
fitted with low-power lights and, for the most part,
without regulatory control systems. Because of the
imperfect horticultural equipment used many of
these experiments failed.
The best result of that period was the successful
growth of arabidopsis (a member of the mustard
family) seeds on the Saylut-7 orbital station in a
Phiton-3 apparatus in 1982. But many later attempts
to repeat this experiment failed.
The Svet greenhouse, a joint project by Russia
and Bulgaria, was the first automated greenhouse
in orbit. It had a larger planting area than previous
devices, a higher vegetation chamber, a much
brighter light system and automatic controls - and it
was also able to process and send to Earth collected
data on the plants’ environment and the conditions
of the greenhouse modules.
In 1990, the first experiment in cultivating pak
choi cabbage and radishes was conducted in
the Svet greenhouse on board the International
Space Station (ISS). The productivity and speed of
ontogenetic plant development (from the earliest
stage to maturity) in this experiment was lower than
in the Earth control group, which again confirmed
the position of those scientists who believed that
weightlessness had a negative impact on plants.
Later, specialists at the Institute of Medical and
Biological Problems (IMBP) at the Russian Academy
of Sciences and the Space Dynamics Laboratory
at Utah State University equipped the Svet
greenhouse with the Gas Exchange Measurement
System (GEMS), which measured hydrocontent
dynamics in the vegetation chamber and plant gas
exchange, as well as controlling the conditions of
plant cultivations.
After in-flight experiments were completed,
control experiments were run on Earth in special
climate-controlled chambers with simulated
dynamics of the main parameters of plant
cultivation, as recorded during the spaceflight. To
provide normal growth and development of plants in
weightlessness, both the correct methodology and
the right equipment to regulate the water and air
settings of the root environment were needed.
The thermo-impulse method of monitoring the
root moisture levels in weightlessness was suggested
and subsequently used, and data obtained on root
moisture levels during these space experiments
provided the necessary information to allow
astronauts to control moisture for the first time in
human spaceflight history.
If at first you don’t succeed…
In 1995 a joint team of Russian and American
researchers attempted to grow super-dwarf wheat in
space for one ontogenesis cycle – ‘from seed to seed’
– in the Svet greenhouse on the Russian Mir space
station. This first attempt was not fully successful;
lamp sets failed and the plants did not form a head,
remaining at the vegetative stage of development. In
Pea flowers in the
‘Lada’ greenhouse.
Michael Foale and
Alexander Kaleri beside
the pea plants growing in
the Lada-4 greenhouse
experiment.
FEEL-GOOD FACTOR
The 1997 Brassica rapa L. experiment was noteworthy not only because of
interesting biological results but also because of the intricate work performed
by astronaut Michael Foale on the manual cross pollination of the tiny Brassica
flowers, all achieved despite the dramatic events of 25 June 1997 when Mir was
depressurised after a collision with a Progress transport ship during a docking
test, which almost cost the crewmembers their lives.
In an interview about his in-flight experiment Michael Foale spoke of the wider
benefits he experienced of the presence of green plants.
“The greenhouse experiment provided me with peace of mind,” he said. “It’s a
special sort of task – to be a gardener, to live together with your plants, to fully
grasp their situation and have a sort of connection with them; it impresses on
you visually and allows you to do the sort of work that’s very different from the
extremely technological environment of spaceflight that lacks so many things.
“It’s a connection with Earth that you take with you and that gives you comfort.
I took great pleasure in checking up on the greenhouse every morning. It was
supposed to take twenty minutes a day, but I spent a lot of time in the greenhouse
and valued that time very much. And I think that during lengthy flights or at any
space station, experiments where something is grown [such as plants] can find a
wide range of uses not only in scientific research but also for psychological support.”
Observations like these - on the psycho-emotional condition of space crews - have
been expressed by almost all astronauts that have participated in plant experiments.
NASA
