02:00 AM

ISS Experiment to Study Flames and Fire Suppression in Space

A combustion experiment jointly designed by scientists and engineers at NASA's Glenn Research Center and the Universities Space Research Association (USRA) is currently in operation onboard the International Space Station (ISS). Dr. Paul Ferkul, a noted scientist with the National Center for Space Exploration Research (NCSER) in Cleveland and Principal Investigator for the experiment, explains that the Burning and Suppression of Solids (BASS) experiment will bridge the gap between normal gravity material flammability screening tests, short time ground-based microgravity tests and actual zero-gravity spacecraft conditions. "The basic applied hypothesis is that we believe that in certain conditions a material in zero-gravity will actually be more flammable than it is in normal gravity."

In space, the lack of gravity provides the opportunity to study a larger range of flame characteristics than could be studied on Earth. The absence of gravity's effects on convection aboard the Space Station or other space vehicle makes flames behave in a different manner. Similarly, suppressing fires in microgravity is different than on Earth, since in microgravity it may not be clear where the base point of a flame is, and the stabilization zone may not be apparent. While microgravity conditions can be achieved on Earth using drop towers, these facilities only provide microgravity for a few seconds. Of particular interest to scientists is the long-duration burn of combustible materials that can only be achieved in space.

The BASS experiment will burn 41 fuel samples (the majority of the samples will be ignited and burned multiple times). BASS will also assess the effectiveness of an inert, gaseous extinguishing agent (similar to that used on ISS) in putting out flames over different materials, in different geometries and at different flows. Astronaut Don Pettit is conducting the BASS experiment within the Microgravity Science Glovebox. The glovebox, designed as an enclosed work area, is sealed to contain fluids, gasses and equipment. Flame and fuel experiments are safely conducted by accessing ports using sturdy sealed gloves and viewing the processes through a large window. The Operations Team will work with Don to position and ignite the fuel samples, control the relative flow speeds, allow time for burning and extinguish the flames. Images and video will be captured and downloaded.

To date, five BASS samples have been successfully burned and extinguished, one of which was reburned three more times to vary air flow and suppression technique. Ferkul describes one test, stating, "After two minutes of burning, the flow was turned off and the flame extinguished rapidly" - supporting the protocol that the best initial response to a fire in microgravity is to turn off any forced air flow. In another test, Ferkul explains, "after about a minute of burning, nitrogen was turned on, and the flame responded, but did not go out. In fact, the flame appeared to get brighter." This new observation in which the nitrogen jet was able to entrain air all by itself will be studied further and has important implications for gaseous fire suppression systems like the one currently employed on the ISS.

"The importance and direct application of the BASS experiment - spacecraft fire safety and astronaut well being - cannot be over emphasized. Wider implications of the experiment, through computer simulations, also apply to many different Earth-bound combustion systems," explains Dr. Don Kniffen, USRA's Vice President for Science.

The National Center for Space Exploration Research (NCSER), a research team led by USRA and Case Western Reserve University, provides on-site microgravity expertise to NASA Glenn Research Center. The NCSER team specializes in reduced gravity fluid mechanics, reduced gravity combustion processes, human physiological systems, theoretical modeling, and advanced technology development.

Universities Space Research Association (USRA) is an independent, nonprofit research corporation where the combined efforts of in-house talent and university-based expertise merge to advance space science and technology. USRA works across disciplines including biomedicine, astrophysics, and engineering and integrates those competencies into applications ranging from fundamental research to facility management and operations. USRA engages the creativity and authoritative expertise of the research community to develop and deliver sophisticated, forward-looking solutions to Federal agencies and other customers - on schedule and within budget.