Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) - 09.13.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

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Science Objectives for Everyone
The Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) experiment examines how the low gravity conditions of space affect the nitrogen fixation process during growth of a well-known legume – microclover. Automated laboratory modules maintain germination and growth conditions while atmospheric nitrogen is measured throughout the mission. The CubeLab is installed aboard the International Space Station (ISS), operates for a period of time and is then returned to Earth-based labs for more detailed analysis. This project was conceived by the Higher Orbits Andromeda division winning team, the Saguaro Snakes (Gilbert, AZ).
Science Results for Everyone
Information Pending

The following content was provided by Gentry Barnett, and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
Michelle Lucas, Higher Orbits, Leesburg, VA, United States

Information Pending

Space Tango, Inc., Lexington, KY, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
National Laboratory (NL)

Research Benefits
Scientific Discovery

ISS Expedition Duration
September 2017 - October 2018

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • Nitrogen fixation is a crucial element of any ecosystem, a natural fertilizer that is necessary for most types of plant growth. Legumes such as microclover are very efficient at converting atmospheric nitrogen into soil nitrogen concurrently with photosynthesis. This process - nitrogen fixation through biological processes (BNF) - is the leading means of production of atmospheric N2 fixation, studied as a means of advancing horticulture through the maintenance of soil fertility due to its efficiency and sustainability.
  • Prokaryotic bacteria (in this case, Rhizobium) develop a symbiotic relationship with the microclover in order to convert atmospheric nitrogen into organic compounds in nodules on the root system of the plant.
  • With the Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) experiment, gaining a better understanding of the BNF process in a microgravity environment could be valuable in advancing technology which aims to progress the field of commercial BNF soil nutrition.

The Biological Nitrogen Fixation in Microgravity via Rhizobium-Legume Symbiosis (Biological Nitrogen Fixation) experiment evaluates the symbiotic legume/bacteria system and how it is affected by microgravity. The experiment includes a plant growth chamber containing a wetted, loamy soil mix, several sprouted microclover seeds, and all required sensors and circuitry. The sealed plant growth chamber regularly measures gaseous nitrogen, which quantifies the rate at which nitrogen fixation occurs. Nitrate levels in the soil are measured pre- and post-flight. Additionally, images of the plant growth are captured throughout the mission.

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Space Applications
The investigation benefits space programs by demonstrating the use of modular automated hardware in space-based agronomic research. The experiment provides information on the space viability of a legume with notable nutrient cycling capabilities, some of which could support habitat design for long-term or landed space missions. The project also demonstrates the use of space as a laboratory by private and public research partnerships.

Earth Applications
The study benefits Earth-based applications by providing information about the growth properties of an important legume under the unusual conditions of microgravity. The experiment analyzes the growth and nitrogen cycling abilities of a plant widely used in soil conservation. Deeper understanding of this plant improves its uses for Earth.

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Operational Requirements and Protocols
This experiment is implemented in a Plant Growth Life Science CubeLab and mounted to Payload Card-4 and Payload Card-7 for ambient ascent. The crew installs the payload card into the TangoLab facility where autonomous operations occur. At the end of operations, the crew removes and stows the hardware for return to Earth. The hardware is returned on the next returning vehicle in ambient conditions, and turned over to the Space Tango/Principal Investigator team during early return either in Houston, or at the California airport.

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Decadal Survey Recommendations

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Results/More Information

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Related Websites
Higher Orbits
Space Tango

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