Similar to the 1981 prehistoric fantasy cult film, NASA is on its own “Quest for Fire” to better understand how flames work in space.
The agency lit about 1,500 flames in six investigations aboard the International Space Station as part of the long-running Advanced Combustion via Microgravity Experiments, or ACME, project. The aim of the project, which began in 2017, utilized the microgravity environment to better understand the physics, structure and behavior of flames.
“This knowledge can help designers and engineers here on Earth to develop furnaces, power plants, boilers and other combustion systems that are more efficient, less polluting and safer,” said Dennis Stocker, ACME Project Scientist at the Glenn Research Center. NASA, in a recent agency statement.
Related: Here are 7 things the International Space Station taught us in 2021
NASA astronauts’ time is precious, so as much as possible, the ACME team sought to run the experiments remotely from NASA’s Glenn ISS Cargo Operations Center in Cleveland.
The experiments, housed within a module within the station’s Integrated Combustion Rack, lasted 4.5 years of in-orbit operations. Although ACME is no longer there — it was removed in February to make way for a new set of fire safety experiments called Solid Fuel Ignition and Extinction, or SoFIE — Stocker said the contribution of the ACME set of experiments was more than originally planned.
“More than 1,500 flames were lit, more than three times the number originally planned,” Stocker said. “Several ‘firsts’ have also been achieved, perhaps most notably in the spherical, cold flame areas.”
The ACME hardware is expected to return to Earth sometime in 2022, NASA noted, and will be repurposed for a new set of experiments going into space in the coming years.
In the words of NASA, the completed experiments are:
- Burning Rate Emulator (BRE) – materials demonstrated can burn for minutes in the absence of airflow in crew vehicle atmospheres being considered for future missions.
- Coflow Laminar Diffusion Flame (CLD Flame) – produced reference data on sooty and highly diluted extremes to improve computational models.
- Cold Flame Investigation with Gases (CFI-G) – resulted in unpremixed cold flames of gaseous fuels without enhancements such as heated reagents, pulsed plasmas or ozone addition, which were required in ground tests.
- Electric Field Effects on Laminar Diffusion Flames (E-FIELD Flames) – demonstrated the potential use of electric fields to reduce emissions from unpremixed flames.
- Flame Design – demonstrated, for the first time, nearly stable unpremixed spherical flames and radiation heat loss leading to the extinction of larger flames.
- Structure and Response of Spherical Diffusion Flames (s-Flame) – provided data on flame growth and extinction to improve computational models.