Starting a fire in space, on purpose

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Engineers plan to intentionally start fires in every Cygnus capsule heading for ISS this year, beginning with the next on Tuesday, but they will wait each time until the freighter has been docked, unloaded, and has left the station.

“The specific goals of the SAFFIRE experiments are to investigate the spread of a large-scale fire in microgravity, essentially trying to answer the questions of how large does a fire get and how rapidly does it spread, or how long does it take to get to the point of being really hazardous to the crew.”

NASA intends to run SAFFIRE experiments on three consecutive Cygnus spacecraft launching through the end of this year. The SAFFIRE 1 and 3 tests will use single samples 15.7 inches wide by 37 inches tall to watch the development and spread of a large-scale low-gravity fire. Scientists want to know if there is a limiting flame size and to quantify the size and growth rate of flames over large surfaces. “SAFFIRE is a box with a wind tunnel in it, a flow duct, that contains the sample that will be burned,” said Ruff. With two cameras poised to capture the fire, a hot wire along the upstream edge of the fiberglass-cotton fabric sample will trigger the burn that should last at least 15 or 20 minutes.

This is very clever, using the capsule as a fire test facility when it is on its way back to Earth to burn up in the atmosphere.

One comment

  • Interesting paper on fire and fire suppression in space: “Fire Safety in the Low-Gravity Spacecraft Environment”. The paper was published in 1999, so the information on suppression systems is a bit dated. The very efficient Halon extinguishers on the Shuttle have been replaced by CO2 systems on ISS, because the Halon was ‘ozone depleting’. If my spacecraft is on fire, ozone depletion is the very last thing on my mind: I want that fire OUT. The Russian sections of ISS use water-based foam, which seems like a case where the cure is almost worse than the disease.

    Of note is the fire on MIR in 1997 couldn’t be extinguished until the initiating oxygen generator ran out of oxygen.

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