[FLARE]
Fundamental Research on International Standard of Fire Safety in Space -base for safety of future manned mission-

RESEARCH OVERVIEW

• Combustion phenomena, including flame spreading over solid materials, is significantly affected by the surrounding flow field. In normal gravity, it is not possible for flames to spread over solid materials under low-speed external flow conditions, since even small flames induce a buoyancy-induced flow no smaller than about 30 cm/sec. In the microgravity environment on the other hand, it is possible for flames to spread over solid materials in an artificially produced flow of less than 30 cm/sec, due to lack of buoyancy-induced flow. Therefore, the effect of gravity’s impact on the flammability of materials through the changing of the surrounding flow field shall be examined by the Fundamental Research on International Standard of Fire Safety in Space – Base for Safety of Future Manned Missions (FLARE) investigation.
• Flame spreading behaviors over various solid materials, under low-speed external gas flow conditions (less than 30 cm/s) parallel to the sample surface, are observed inside the flow tunnel. Oxygen concentrations that can extinguish the spreading flame are measured with varying external flow velocity and directions. As a result, minimum limiting oxygen concentration (MLOC), in which flame spread is sustained in microgravity environment, is revealed for the tested samples.
• MLOC data in microgravity for various solid materials with multiple sample configurations (flat, rod, and insulated wire) are obtained systematically for the first time. Comparison between MLOC data and the results of flammability tests at normal gravity quantitatively reveals the gravity impact on the materials’ flammability. Also, verification of the predicted MLOC, which is based on the developed new methodology, demonstrates the basis of the planned new international standard on evaluation of materials flammability in microgravity environment.

DESCRIPTION

Fundamental Research on International Standard of Fire Safety in Space – Base for Safety of Future Manned Missions (FLARE) is an investigation by the Japan Aerospace Exploration Agency (JAXA) that evaluates the impact of the microgravity environment of space on the combustion of solid materials for the improvement of fire safety in space. In the Multi-purpose Small Payload Rack (MSPR) in the Kibo module, FLARE evaluates the flame spread behaviors over various solid fuels with flat, rod, and insulated wire configurations.

Low-speed opposed, and concurrent gas flow conditions, are observed inside the flow tunnel of the experimental apparatus, to find the minimum limiting oxygen concentration (MLOC), in which flame spread is sustained in the microgravity environment. This MLOC data is compared with the predicted results to verify a new methodology developed through the ground research. The new methodology is to become the basis for a planned new international standard on the evaluation of materials flammability in the microgravity environment.

SPACE APPLICATIONS

Low-speed external flow conditions, only achieved in microgravity, enhance the flammability of materials. Current materials flammability screening tests for manned space missions do not consider the effect of gravity. The investigation demonstrates a new way to predict flammability in microgravity that could fill this gap and significantly improve fire safety aboard spacecraft on future exploration missions.

EARTH APPLICATIONS

New methods for evaluating the flammability of materials in high flow velocity conditions have potential applications for evaluating and reducing fire hazards on Earth.

OPERATIONAL REQUIREMENTS AND PROTOCOLS

The Solid Combustion Experiment Module (SCM) is assembled on-orbit by a crew member, and is installed in Multi Purpose Small Payload Rack (MSPR) Work Volume (WV). The Gas Bottle is installed in the MSPR Small Experiment Area (SEA). After the setup, the investigation is operated from ground crews at the Space Station Integration and Promotion Center (SSIPC) at the Tsukuba Space Center.

The investigation procedure is as follows:

1. Preparation (activation and initial setting (MSPR, SCM))
2. During investigation (sample/O2 concentration/air pressure/air flow setting, ignition, observation of combustion phenomena)
3. Post experiment (downlink of recorded video/pictures, vent of combustion gas and air supply)
4. Closeout (deactivation of facilities).