Similar to the 1981 cult prehistoric fantasy film, NASA is on its own “Quest for Fire” to better understand how flames work in space.
The agency has lit about 1,500 flames in six surveys aboard the International Space Station, as part of the long Advanced combustion via microgravity experiments, or ACME, project. The focus of the project, which began in 2017, used the microgravity environment to better understand the physics, structure and behavior of flames.
“This knowledge can help designers and engineers here on Earth develop more efficient, less polluting and safer furnaces, power plants, boilers and other combustion systems,” said ACME project scientist Dennis Stocker. at NASA’s Glenn Research Center, in a recent agency statement.
Related: Here are 7 things the International Space Station taught us in 2021
NASA astronaut time is valuable, so where possible the ACME team sought to conduct the experiments remotely from NASA’s Glenn ISS Payload Operations Center in Cleveland.
The experiments, housed inside a module inside the station’s Combustion Integrated Rack, spanned 4.5 years of on-orbit operations. Although ACME isn’t around anymore — it was axed in February to make way for a new set of fire safety experiences called Solid Fuel Ignition and Extinction, or SoFIE — Stocker said the set’s contribution ACME experiments was more than originally expected.
“Over 1,500 flames were lit, more than three times the number originally planned,” Stocker said. “Several ‘firsts’ were also achieved, perhaps most notably in the areas of cold and spherical flames.”
ACME’s hardware is expected to return to Earth sometime in 2022, NASA noted, and will be reused for a new series of experiments going to space in the coming years.
In the words of NASA, the completed experiments are:
- Burn rate emulator (BRE) – materials demonstrated can burn for minutes in the absence of airflow in the atmospheres of crew vehicles being considered for future missions.
- Coflow laminar diffusion flame (CLD Flame) – provided benchmark data at sooty and highly dilute extremes to improve computer models.
- Investigation of cold flames with gases (CFI-G) – resulted in cold, unmixed flames of gaseous fuels without enhancements, such as heated reagents, pulsed plasmas, or the addition of ozone, which were required in ground testing.
- Electric field effects on laminar diffusion flames (E-FIELD Flames) – demonstrated the potential use of electric fields to reduce emissions from non-premixed flames.
- flame design – demonstrated, for the first time, quasi-stationary non-premixed spherical flames, and radiative heat loss leading to extinction for larger flames.
- Structure and response of spherically diffused flames (s-Flame) – provided data on flame growth and extinction for the improvement of computer models.