In this 13-part series of articles, The Combustion Institute recognizes the 2023 Distinguished Papers selected from among the scientific papers presented during the 39th International Symposium on Combustion. Congratulations to Yusuke Konno, Yutao Li, Jean-Marie Citerne, Guillaume Legros, Augustin Guibaud, Nozomu Hashimoto, and Osamu Fujita for winning the DPA in the Fire Research colloquium.

When asked about the motivation for their paper, “Experimental study on downward/opposed flame spread and extinction over electric wires in partial gravity environments,” Yusuke Konno, representing his group, pointed to the advancement of human space exploration due to the U.S.-led Artemis program. This program expands the astronauts’ sphere of activity from Earth’s orbit to the surface of the moon and Mars. As fire has been identified as a major hazard in space exploration, there is an increasing need to manage new risks in partial gravity environments. This research was conducted by Japanese and French teams to contribute to fire risk management related to space travel in partial gravity.

In this research, the scientists aimed to experimentally clarify that the flammable range of materials is greater at intermediate gravity levels than reported on the ground. The result suggests that materials that are assumed to be non-flammable on the ground may be flammable in a low gravity environment. This should be considered when evaluating the flammability of materials used in manned space missions. Of note, results also differ from past microgravity observations.

In the long term, the team anticipates that the experimental data obtained from this study will offer valuable insights to address not only fire safety issues but also crucial processes such as heat utilization and waste management in low-gravity environments. The waste disposal method being used currently for manned space stations would not be viable on the moon or Mars. Dr. Konno stated that the team believes that combustion might serve as an efficient solution for waste management in these extraterrestrial environments. After testing, they believe that their findings will be indicative of a benefit of using combustion in a low gravity environment.

Konno, Li, Citerne, Legros, Guibaud, Hashimoto and Fujita discern that the primary beneficiaries of their findings are the space agencies responsible for managing human space missions. This research has generated valuable experimental data regarding the combustion characteristics of materials in low-gravity environments. These findings are essential for space agencies as they consider material selection for use in such missions. The fundamental knowledge gained through this study aids in ensuring the safety and effectiveness of future space missions.

Travel was nearly impossible in 2020 when this research was being done due to the COVID-19 pandemic. Under a formal agreement between the French Space Agency (CNES) and the Japanese one (JAXA), the flight experiment was carried out in France by a French research team, building on joint inputs from both teams. Then, experimental data was transferred to Japan, and data analysis was performed primarily by a research team at Hokkaido University. Despite some of the team’s inability to join the experiment in person, they consistently had virtual communication which played a pivotal role in facilitating their research. Although tests were conducted in December 2020 (and the data published in a paper in December 2021), they are part of an international project that has been sustained for almost a decade.

Over 1,500 papers were submitted to the 39th International Symposium on Combustion. All papers were categorized into one of 13 colloquia, and then distributed to Colloquium Coordinators and Co-Chairs. Each paper received at least three reviews from qualified individuals through the peer-review process. Less than 50 percent of the papers submitted were accepted for presentation.

Following the symposium, one paper presented in each colloquium is awarded the distinction of Distinguished Paper. Visit here to view the presentation. The 13 Distinguished Papers undergo committee review for consideration for the Silver Combustion Medal. A paper selected for this honor exemplifies quality, achievement, and significance to advance a field of combustion science, and will be awarded during the 40th International Symposium in Milan, Italy.