Lada: The ISS Plant Substrate Microgravity Testbed

Abstract

Lada, named for the ancient Russian Goddess of Spring, is a plant growth system developed jointly by the Space Dynamics Laboratory and the Institute of Biomedical Problems for long- term deployment on the International Space Station. Lada uses design features and technology similar to the Svet greenhouse on the Mir orbital outpost, and will be launched to ISS in June 02. It is scheduled to support its first crop (a leafy vegetable - Mizuna (Brassica rapa var. nipposinica)) in October 02. Lada consists of four major components (a control module, two vegetation modules and a water tank) and is designed to be deployed on a cabin wall. This deployment scheme was chosen to provide the crew therapeutic viewing and easy access to the plants. The two independently controlled vegetation modules allow comparisons between two vegetation or substrate treatments. The vegetation modules consist of three sub-modules, a light bank, the leaf chamber, and a root module. The root module is 9 cm deep, and can be instrumented to allow a wide range of substrate water and oxygen diffusion experiments to be conducted during the plant growth experiments. Sensors available in Lada are similar to those provided by the Svet-GEMS system. Specific attention has been paid to the root zone sensor suite, which includes substrate moisture probes, mini- tensiometers, and substrate oxygen sensors. Experiments conducted in Lada will be associated with the Russian National Science program and will follow three themes: substrate management physics, plant production and quality, and crew - plant interaction studies. A unique feature of the Lada concept is that when the system is not being used for supported science experiments, it will be available to crew members to supplement their diet and to enhance flight enjoyment. Plans are in place to train all of the Russian crew members to use Lada. International cooperative experiments exploiting these unique features are now being developed.

Full text

PAPER NUMBER 2002-01-187
LADA: THE ISS PLANT SUBSTRATE MICROGRAVITY TESTBED
Gail E Bingham, T. Shane Topham and John M. Mulholland
Space Dynamics Laboratory, Logan, Utah 84341
I.G. Podolsky
Institute of BioMedical Problems, Moscow, Russia
Copyright © 2001 Society of Automotive Engineers, Inc
ABSTRACT
Lada, named for the ancient Russian Goddess
of Spring, is a plant growth system developed
jointly by the Space Dynamics Laboratory and
the Institute of Biomedical Problems for long-
term deployment on the International Space
Station. Lada uses design features and
technology similar to the Svet greenhouse on
the Mir orbital outpost, and will be launched to
ISS in June 02. It is scheduled to support its
first crop (a leafy vegetable – Mizuna [Brassica
rapa var. nipposinica]) in October 02. Lada
consists of four major components (a control
module, two vegetation modules and a water
tank) and is designed to be deployed on a cabin
wall. This deployment scheme was chosen to
provide the crew therapeutic viewing and easy
access to the plants. The two independently
controlled vegetation modules allow
comparisons between two vegetation or
substrate treatments. The vegetation modules
consist of three sub-modules, a light bank, the
leaf chamber, and a root module. The root
module is 9 cm deep, and can be instrumented
to allow a wide range of substrate water and
oxygen diffusion experiments to be conducted
during the plant growth experiments. Sensors
available in Lada are similar to those provided
by the Svet-GEMS system. Specific attention
has been paid to the root zone sensor suite,
which includes substrate moisture probes, mini-
tensiometers, and substrate oxygen sensors.
Experiments conducted in Lada will be
associated with the Russian National Science
program and will follow three themes: substrate
management physics, plant production and
quality, and crew – plant interaction studies. A
unique feature of the Lada concept is that when
the system is not being used for supported
science experiments, it will be available to crew
members to supplement their diet and to
enhance flight enjoyment. Plans are in place to
train all of the Russian crew members to use
Lada. International cooperative experiments
exploiting these unique features are now being
developed.
INTRODUCTION
A new greenhouse of the Svet style is being
prepared for deployment in the Russian section
of the International Space Station (ISS). Svet
was used for seven experiments on Mir between
1990 and 2000. In these seven formal
experiments, 12 crops were grown from seed to
harvest, resulting in the most successful
Microgravity (µg) plant experiment sequence
ever completed. These international
experiments laid the groundwork for many of the
new plant growth activities that are being
planned for the ISS, and provided several
keynote discoveries and demonstrations in the
last decade. These include: the development of
a reliable substrate moisture control system
(Ivanova and Dandolov, 1992; Bingham et al,
1996; Bingham et al., 1999; Jones and Or,
1999), the identification ethylene as the limiting
factor in earlier seed to seed failures (Salisbury,
1997; Campbell et al, 2001) and the
identification of the likely ethylene source
(Bingham et al, 2000). This experiment
sequence also included the first replicated seed
to seed experiment (Brassica rapa L. Musgrave
et al., 2000), and the first two-generation
microgravity seed production experiment
(Sytchev et al., 1999; Bingham et al, 2000). The
Svet-GEMS system also hosted the first salad
crop experiments conducted in µg (Ivanova et al,
1992; Levinskikh et al, 2001), culminating in a
cosmonaut taste test of salad greens aimed at
future efforts to supplement the flight diet.

Lada was developed under a joint cooperative
agreement between the Institute of Bio-Medical
Problems (RAS, Moscow, Russia) and Space
Dynamics Laboratory / Utah State University.
Lada has completed qualification and
biotechnology testing and is expected to launch
to the ISS in mid 2002. Lada was developed to
allow the Russian National Program on
Microgravity Plant Technology to continue into
the ISS era. Cooperation with other
International partners is being sought for
experiments utilizing Lada.
DESIGN CONSIDERATIONS
The Lada design follows the basic principles of
the Svet-GEMS system, in that it is a wall
mounted system optimized to provide long term,
ready access for cosmonaut interaction. Like
Svet, it provides light and root zone control, but
relies on the cabin environmental control
systems for humidity, gas composition, and
temperature control. That is, cabin air is pulled
into the leaf chamber, flows over the plants and
vents through the light bank to provide both gas
exchange and light bank ventilation. Wall
mounting in the crew cabin with sliding door
access to the plants, allows ready access to
plants by cosmonauts, providing a kind “walk in
the garden” psychological boost for the crew.
Unlike Svet, Lada uses two separate leaf
chambers to allow treatment comparisons. The
total plant growing area is one half that of Svet,
but is divided into separate Vegetation Modules
so that the treatments do not interact. The Svet
root module was divided into two zones,
allowing substrate conditions to be varied, but
the plant vegetation area shared the same leaf
chamber and lighting system. A more vigorously
growing treatment in one root area could expand
and shade the comparison crop. With Lada, the
root module, leaf chamber and light bank for the
two systems are completely separate. Lada
utilizes the same type of lighting and substrate
moisture control technology and approaches
that were present in Svet, but with lower volume
and power requirements. Commercial, off the
shelf components are used extensively in Lada.
While Lada provides extensive leaf chamber
light and temperature measurements, the most
significant diagnostic effort is centered on the
root zone. Lada root modules have the same
plant growth area as the BMPS, but the depth is
9 cm to allow full root development for long
experiments. Sensors for moisture, matric
potential and substrate oxygen concentration
can be mounted at various levels to measure
profiles in the root zone.
LADA COMPONENTS
Lada was designed to provide the same good
plant growth conditions and measurement
capability that were provided by the Svet –
GEMS system, except photosynthesis and
transpiration. This section provides additional
description of the individual modules.
Figure 1: The Lada Greenhouse was developed by
SDL and IBMP for the Zvezda module of the ISS.
CONTROL AND DISPLAY MODULE
This module contains the power converters, the
data acquisition and control system and the
display and data storage unit. The system
provides manual and automatic control of all
Lada functions, including substrate moisture,
light period, photography, measurement period
and data and command communications. It also
provides power and data interfaces for future
modules such as animal or aquatic habitats.
The Lada Control Module is shown in the upper
center of Figure 1. The upper portion of the
control module is a display and interface unit,
which provides long term program and data
storage and data display functions. It also has
connectors to support external hardware such
as a 3.5 FDD, PS/2 mouse, and parallel printer.
The upper section also has an RS232 serial
connection that is wired in parallel to the lower
section. This connection allows control module
operations to be conducted from a separate
laptop computer, should the display terminal fail.
The display terminal also has a DC 16V-in
connection for operation when 28 VDC power is
not available, a USB port, an infrared port, and a
PCMCIA slot.

The display terminal is a modified Casio
Cassiopeia FIVA model MPC-101M62E display
terminal and is used in conjunction with the Lada
Software System (LSS) to provide a user-
friendly interface to Lada. The user has access
to the control module and can visualize data
through the display terminal. Data on the
display terminal hard disk can be backed up on
an IBM 340MB microdrive. The microdrive is
inserted into the PCMCIA slot of the display
terminal . A separate microdrive contains a
compacted version of the display terminal
operating system as well as an LSS installation
program. If data on the display terminal internal
hard drive is lost or if the hard drive is not
functioning properly the display terminal can be
run from programs on the microdrive, or can be
used to re-establish the software on the terminal
hard disk.
The lower section of the CM houses a CR10X
microcontroller and data logger, the DC/DC
power converters, and various other circuit
boards. All voltage measurements from the
growth module and instructions from the display
terminal for the growth module are processed in
the lower section.
The switches and LEDs on the front of the CM
control and display the status of the Lada power
conversion and distribution system, including the
availability of 28V power from the ISS. Between
the upper and lower sections of the CM are four
connectors: a USB port, 9-pin RS232 serial port
(display terminal to CR10X), 4-pin power
connector (2 pins for 16V power supply to the
display terminal, 2 pins for the CR10X back-up
battery), and a 2-pin O
2
sensor connector.
A power supply board, the CR10X, and two
AM25T input multiplexer boards are connected
to the 4 64-pin connectors of the main control
board. Two communication connectors are
located on the bottom of the CM. These
connect to the growth modules via standard
SCSI cables.
The CR10X in conjunction with LSS provides
automatic control of greenhouse actuators and
saving of plant growth data. The CR10X can be
set to record data to memory every 20 minutes
or every hour. The CM houses a cabin air
temperature sensor, cabin absolute pressure
sensor, cabin relative humidity sensor, cabin air
oxygen concentration sensor, and a cabin air
carbon dioxide concentration sensor. The cabin
air temperature sensor incorporates a copper
constantan thermocouple. The control module
includes a cabin oxygen partial pressure sensor
which is designed for easy replacement (every
two years).
GROWTH MODULE
The LADA Growth Modules (GM) are the two
outside components in Figure 1. The Growth
Module supports the plants, and consists of
three sub-modules, the Root Module (RM), the
Leaf Chamber (LC) and the Light Module (LM).
Each GM provides a 14 x 18 cm (252 cm
2
) plant
growth area.
Root Module
The root module consists of three sections, a
sensor connection tray (bottom), a water
distribution assembly (right), and the substrate
and sensor container. The root module is made
of black Delrin and is designed to provide ideal
substrate conditions for plant growth. The
control panel of the RM sensor sensor
connection tray (see Figure 2) provides control
switches for the primary (PUMP 1) and backup
(PUMP 2) water pumps. Each 3-position locking
switch is housed with a green led. In AUTO
(left) position the LED lights up indicating the
CR10X has control of the respective pump. In
“OFF” and “ON” position the pump is manually
turned off or on, respectively.
Figure 2: The Root Module has the three sections, the
substrate container, the sensor interface tray on the
bottom (with pump controls), and the water
distribution section (which contains the pumps).
On the lower right side of the RM is a 9-pin
communication connector for connection with
the pumps, and a switch for selecting for which
pump the CR10X will monitor. A 40-pin
connector is located on the lower left side of the
RM to provide communications and power from
the CM, via the Light Module.

The substrate- and sensor-containing portion of
the RM (see Figure 3) is made of black Delrin
and has 20 threaded sensor holes in the bottom
for various sensors placement per experiment
specifications. Plugs are placed in the
remaining unused holes. In the initial
operations, the RM is filled with a porous
(Turface1-2 mm) substrate. Osmocote time
release fertilizer is used with the substrate. On
the inside of the RM running lengthwise are 4
porous SS water tubes connected to the water
distribution assembly using PUMP 1. The
pumps are small commercial peristaltic units,
powered by a switched DC circuit. The Lada
RM uses the coated fabric wick material which
was used in the Svet RM, The wick is folded
around the porous tubes to support the seeds.
The RM are configured to support up to 16
sensors, including four O
2
concentration
sensors, six soil moisture probes (which also
function as temperature sensors), two wick
moisture probes, and four micro tensiometers.
The levels of all of the sensor types can be
adjusted when the root module is packaged,
depending on experiment requirements. The
flexible wick moisture probes are placed
lengthwise inside the wicks. The wick moisture
probes and soil moisture probes are a thermal
pulse type similar to those used in Svet. The
mirco tensiometers are primed when the
substrate is wet in flight, using the backup pump.
Figure 3: The top view of the inside of the Root
Module, showing one of the sensor arrangements and
the water wicking system.
The water distribution section on the right side of
the RM contains two DC peristaltic Pumps.
Three quick connectors are located on the
bottom of the box, providing water into and out
of the system. One line connects Pump 1 to the
water tank, providing the water storage for the
system. The pump 1 output is connected to
water distribution lines that feed to the four
porous tubes in the substrate container. Each
pump is visible from the front side of the RM
designated by the labels “PUMP 1” and “PUMP
2” and is equipped with a magnet that is
monitored by hall-effect sensors mounted on the
lower side of the pumps. Because the CR10X
has only two pulse ports and the CM is built to
handle two growth units, only one hall-effect
sensor can be active at one time. A manual
switch is provided to allow either pump to be
monitored. Pump 2 is used to prime the
differential pressure transducers. It can also be
configured as a backup to Pump 1, should it fail
during a growth experiment.
An air channel assembly consisting of an air
channel and air channel cover is mounted on the
top of the RM to contain the substrate, isolate
the plant support wicks, and to provide an air
inlet at the base of the leaf chamber. Two
brackets on the air channel are used with
latches on the leaf chamber to connect the two
components. The air channel is designed with
four air channels and two foliage growth
channels. There is a channel on each side of
the two foliage growth openings. The two
foliage growth openings on the channel cover
match those of the air channel. In the cover is a
series of holes along each channel of the air
channel. The diameter of the holes increases as
air flows toward the farther end assuring even
airflow to the LC.
Wick
O
2
Sensors
Tensiometers
Moisture Probe
Wick
O
2
Sensors
Tensiometers
Moisture Probe
Leaf Chamber
The Leaf Chamber (LC), see Figure 4) protects
the plant vegetation and provides the physical
connection between the RM and the LM. It is
basically a hollow box tube, 25 cm in length,
which can be easily exchanged to support
shorter or taller plants. The LC reflects light
back into the canopy and supports the canopy
variable measurement system. Reflective film on
the inside of the LC maximizes light use,
reflecting it back to the plants. In the front side of
the leaf chamber is a large Lexan window, also
covered with a reflective tape, which can be
opened to allow observation of plant foliage and
collect samples. A latch on the window prevents
inadvertent opening during transport.
Light Module
The light module sits at the top of the growth
module above the LC. The front panel of the LM
Figure 5
) contains the fan and light operation

switches. The design of the two locking
switches inhibits inadvertent switching. Green
LEDs mounted with the switches indicate the
CR10X is controlling the respective device when
the switch is in the “AUTO” position. In the
“OFF” and “ON” position the device is manually
turned off or on, respectively.
Figure 4: Lada Leaf Chamber containing two rows of
Mizuna, the canopy temperature and light distribution
measurement (sensor) tree.
Two 5cm fans are mounted on top of the LM.
These fans pull air through the air channel
assembly on the top of the RM, and up through
the LC to provide controlled vertical flow
ventilation to the plants. Fan activation is
controlled by the CR10X when the “LIGHTS”
switch is in the “AUTO” position. A third small
fan is mounted on top of the sensor tree
connector inside the module to aspirate the
canopy air temperature sensors. The sensor
tree provides PAR and canopy temperature at 3
levels, while a separate thermocouple measures
the input air temperature at the bottom of the
canopy. The temperature of the air exiting at the
top of the canopy is measured using the
thermocouple reference PRT probe on the
bottom of the LM. Two, crew replaceable U-
shape florescent lights are located in the LM
(Figure 6) to illuminate the LC volume, They
provide a PAR of over 230 µmol m
-2
s
-1
at the
top of the RM to support initial plant growth, and
are controlled by the CR10X when the “FANS”
switch is in the “AUTO” position.
The light module contains a relative humidity
sensor, an infrared leaf surface temperature
sensor, a ballast temperature monitor, and the
reference temperature sensor for the
thermocouples used to measure the canopy
environment. A USB camera is mounted at the
bottom side of the LM and is controlled by the
FIVA in the CM. This camera takes pictures of
the foliage as specified by the user in the Lada
Software System (LSS).
Sensor Tree
Air
Temperature
Light
Sensor Tree
Air
Temperature
Light
Figure 5: The front view of the Lada Light
Module, showing the fan and light control
switches.
IR Thermometer
Lamp
Camera
IR Thermometer
Lamp
Camera
Figure 6: The Light Module, showing the lamps,
sensors and interface connections and camera.
WATER TANK
The Water Tank (WT, see Figure 7) is a Lexan
cylinder with two aluminum ends and two Teflon
water bags. The internal bag connector bolts to
the water tank end plate, and has a water feed
tube that passes through to a protected quick
connection. The bag is oversized that when
filled with water it fills the cylinder and cannot
burst. The WT is filled by a connecting tube to
the ISS water supply or to an EDV storage
volume using a single use sterilized adapter.
Once filled, the WT is connected to PUMP 1 for

normal operation or to PUMP 2 to prime the
tensiometers.
Figure 7: LADA Water Tank holds 5 liters of water and
can be refilled from the ISS EDV system.
LADA CONTROL SYSTEM
Actuators on various hardware components and the
Lada Software System (LSS) control the Lada
greenhouse. Lada uses two computers to provide
display, control, data acquisition, storage, and data
communications. The interfaces between the
computers and components are shown in Figure 8.
The basic system storage for all software is the hard
disk of the CM display unit. The CR-10X data
collection and control software is downloaded to the
CR-10X from the FIVA. Once installed on the CR-
10X, they are battery backed in case of power failure.
The CR-10X has limited channel input and control
output capability, and
Figure 8: LADA control, data acquisition, and
communications hardware schematic. The instrument
controller (CR-10X) provides that actual data
collection and control functions for Lada.
so two multiplexers and a Control Actuator card
are used with the CR-10X to form the data
collection and control functions. The Serial and
USB 2 connectors are internal to the CM and
provide interface links to the CR-10X and the
cameras in the PCs.
LADA SOFTWARE SYSTEM
LSS provides a user-friendly interface to the
Lada hardware. It guides the user through
proper adjustment of the control set points and
manipulation of greenhouse actuators. The
software is used to set the environmental
parameters that will be used by the CR10X in
the CM to control the growth chamber(s) and
monitor and save plant growth data. LSS allows
the user to change all control parameters of the
Lada greenhouse when Lada actuators are in
AUTO mode and indicates which actuators are
to be manually manipulated during various
procedures. LSS allows for manual, software-
manual, and automatic operation of the Lada
greenhouse. LSS transfers parameters to the
CR10X data measurement and control system,
and downloads data from the CR10X to be
displayed and saved to disk.
Figure 9: LSS Main Screen allows the user to select
the major program modules.
LSS provides a user-friendly interface for the
CR-10X controller. Plant growth archival files
are saved to hard disk for transmission to
ground controllers. LSS is also used for guiding
the user through various procedures by
providing visual and textual descriptions of steps
to be performed within the procedures. When
the display system boots up, the LSS main
screen (See Figure 9) appears, providing
primary functional options.
The Set Up module
leads the crewmember
through the installation procedure. Hard copy
documentation is only required to apply power to
the system. Once power is applied and the
display unit is booted, the Set Up module
provides to assembly and test instructions for
the system.

The Check Out Module is used to check system
function after Set Up has been completed. It
tests and displays all of the system voltages,
control functions, and makes initial
measurements on all of the sensors. A tabular
report is prepared at the end of the program,
along with a picture from each of the cameras.
The Wet Up Module
is used to wet the root
module. The user can select the amount of
water to be injected, and this module will inject
small doses until that amount has been
delivered. The substrate moisture sensors are
read at regular intervals (20 minutes or every
hour) to document the wet up processes. At the
end of the wet up process, the data collected
from the sensors and pump counts are stored to
a data file that can be down linked for processes
validation.
The Grow Module
provides the readout and
control interface for the plant growth period. It
contains the main functionality of the program.
Unlike the previous modules, which are
essentially single string automatic processes
that flow from step to step, the Grow button
connects to another multi-threaded control and
display interface screen. The functions provided
by this screen are detailed in the next section.
The Help Module
provides access to the
onboard documentation system. This is a
searchable text and picture document in HTML
format, which provides the crew with system
details, troubleshooting and operational
instructions, as required.
The Languages Button
toggles the display text
for each button and message between Russian
and English. This button provides a default
option at the beginning of the program, and all
following options are displayed in the selected
language. The Language option can also be
toggled anywhere in the system by a display unit
function key.
THE GROW SCREEN INTERFACE
Pushing the “Grow” key on the initial welcome
screen brings the user to the LSS main function
user interface. This screen provides the user
with all of the control options and variable
displays required to set up and monitor plant
growth in Lada. The “Grow” screen is shown in
Figure 10.
Figure 10: The “Grow” user interface screen in LSS.
The Grow interface provides several icons to
activate pull down option windows, manages
connection to the CR-10X instrument interface,
and provides three graphical displays. The
displays (white windows in Figure 10) operate as
strip charts for the selected variables. An Icon
Bar extends across the top, providing access to
required system functions. These are (from left
to right): The Graph icon (upper left) sets up the
chart windows. The camera icon allows the
crew person to take a manual picture and to
view previously taken pictures. The Disk icon
provides data transfer from the display hard disk
to the microdrive or the Floppy. The Root icon
controls the commands for manual substrate
moisture sampling and displays the values from
last automatic measurement. A Screwdriver
icon provides a pull down window with buttons
for all control functions. The History Icon shows
the event file, for review of automatic and
manual control events, while the Error Icon
provides a text history of any software errors.
The Language and Help buttons are the same
as those on the Welcome screen, while the Exit
icon returns the user to the Welcome screen.
The windows to the right of the bottom chart
provide digital chart values for the cursor
position, and tells LSS how many and which
chambers are attached, and the CR-10X time.
This time window is useful to know if the charts
are up to date.
EXAMPLE DATA
During the recently completed qualification test
series, a crop of Mizuna was grown from seed to
harvest at 20 cm tall. Lada was placed in the
automatic control mode, with the set point
adjusted between 85 and 90% for the growth
period. Figure 11 shows example data for a

portion of the test, showing a probe near the
bottom, middle and top of the root module, along
with one of the wick sensors. The top sensor
showed more variability in its reading than the
sensors that were lower in the substrate. As the
canopy closed, the amount of water used by the
crop increased dramatically, approaching 300 ml
of water per day. As the rooting became more
effective, the top substrate probe and the wick
sensor moved closer to the same substrate
moisture level.
CONCLUSIONS
Lada has completed its qualification testing and
is nearly ready to ship to Russia for launch to
the ISS. Under the Russian plan, it will remain
on ISS, to support both crew “gardening” and
scientific exploration. New root modules and
supplies will be sent up as required, to meet
program needs. One option being studied to
minimize uplift requirement, is to use a longer
life fertilizer in the root zone. This is currently
under test in both Russia and the U.S. This
would allow multiple crops to be grown in a
single module, a technique that was first utilized
in Svet. The experiments Greenhouse 4 and 5
(wheat) and Greenhouse 6 (salad) were grown
in the same root module.
Figure 11: Substrate moisture control data from the
Lada Biotechnology test.
A unique feature of the use plan will be allowing
the crew to use Lada to grow vegetables for diet
and recreational use when it is not being used
for scientific experiments. All Russian
crewmembers will be trained to operate Lada.
Figure 12: A 20 cm tall Mizuna crop, ready to eat.
For the first time, crew crop growing will not be a
“bootleg” operation. In this respect, Lada will add
a new aspect to plant µg research, the study of
Crew – Plant interactions, including the
psychological aspects. While we, in conjunction
with the Russians have conducted several
ground studies of the advantages of crew-plant
psychological benefits, we know of no formal
studies that have been conducted in space.
REFERENCES
Bingham, G.E., S.B. Jones, I. Podolski, B.
Yendler. 1996, Porous Substrate Water
Relations Observed during the Greenhouse II
Flight Experiment (MIR Space Station - 1995).
SAE Technical Paper Series No. 961547, 26
th
International Conference on Environmental
Systems, Monterey, CA, July 8-11
Bingham G. E., Podolski I. G., Lebinskikh M.A.,
Ivanova T., Kostov P., Sapunova S., Dandolov
I., Bubenheim D. B., Jahns G. 1999.
Microgravity Effects on Water Supply and
Substrate Properties in Porous Matrix Root
Support Systems. Acta Astronautica, vol. 47, pp.
839-848.
Bingham, G.E., M.a. Levinskikh, V.N. Sytchev
and I.G. Podolsky. 2000. Effects of gravity on
plant growth. Jour. Grav. Physiol. V 7(2) 5-8.

Campbell W. F., Salisbury F.B., Bugbee B.,
Klassen S., Naegle E., Strickland D. T.,
Bingham G. E., Levinskikh M., Iljina G. M.,
Veselova T. D., Sytchev V. N., Podolsky I.,
McManus W. R., Bubenheim D. L., Stieber J.,
Jahns G. 2001. Comparative floral development
of Mir-grown and ethylene-treated earth-grown
SuperDwarf wheat. J. Plant Physiol, vol 158,
pp. 1051-1060.
Jones, S.B., and D. Or. 1999. Microgravity
effects on water flow and distribution in
unsaturated porous media: analyses of flight
experiments. Water Resour. Res. 35(4):929-
942.
Ivanova, T. N., and I. W. Dandolov. 1992.
Dynamics of the controlled environment
conditions in Svet greenhouse in flight. Comptes
rendus del’Academiebulgare Science 45 (3): 33-
35.
Ivanova, T. N., Y. A. Berkovich, A. L. Mashinsky,
and G. I. Meleshko. 1992. The first space
vegetables to be grown in the Svet greenhouse
by means of controlled environmental
conditions. Microgravity Q. 2 (2): 109.
Levinskikh, M. A., V. N. Sytchev, T. A.
Derendyaeva, O. B. Signalova, F. B. Salisbury,
W. F. Campbell,G. E. Bingham, D. L.
Bubenheim and G. Jahns. 2000. Analysis of The
Spaceflight Effects on Growth And Development
of Super Dwarf Wheat Grown in the Svet
Greenhouse. J. Pl. Physiol., J. Plant Physiol.
156:522--529
Levinskikh,M.A., V.N.Sychev, I.G.Podolsky, and
G.E.Bingham. 2001.The Pioneering space
experiments aimed at obtaining plant biomass
as an alimentary supplement to space crew’s
food ration. Gravitational and Space Biology
Bulletin, 15(1), #128, p 53
Musgrave M. E., A. Kuang, Ying Xiao, S. C.
Stout, G. E.Bingham, L.G. Briarty, M. A.
Levinskikh, V. N. Sychev, Igor G. Podolski.
2000. Gravity independence of seed-to-seed
cycling in Brassica rapa. Planta, vol. 210, pp.
400-406.
Salisbury, F.B. 1997. Growing Super-Dwarf
Wheat in Space Station Mir. Life Support and
Biosphere Science. V 4, pp 155-166.
Sytchev, V.N., M. A. Levinskikh, I.G. Podolsky,
G.E. Bingham.
.
1999. Final Plant Experiments on
Mir Provide Second Generation Wheat and
Seeds. Gravitational and Space Biology Bulletin,
13(1), #97, p 48.