Spaceship fires are an unpredictable and dangerous situation that can have serious consequences. Apollo 1, which was expected to be the first manned Apollo mission, never got off the ground due to a fire that killed the crew. There have been other fires on spaceships; for example, on the Russian space station Mir in 1997.

To understand how fire behaves on spacecraft, NASA launched Project Saffire, an experiment in spacecraft fire safety, in 2016. Saffire was an eight-year, six-mission program to study the behavior of fire in space. Following completion of the ISS delivery missions, an unmanned Cygnus cargo ship was used in each mission. Various experiments were conducted inside the ship, where a flammable mixture containing cotton and fiberglass was ignited. The researchers also tested the combustion of various materials, such as flame-resistant Nomex fabric and acrylic spacecraft windows. The experiments also varied atmospheric pressure, composition and oxygen levels to gather as much information as possible about the behavior of the fire on the spacecraft.

The final phase of the Saffire-VI program, which took place on January 9, 2024, was special. In this experiment, oxygen levels were increased and pressure was reduced to create conditions as close to reality as possible in a spacecraft.

The main goal of Saffire research is to understand how a fire affects the crew and the ship. When burning in a closed space, various toxic substances such as hydrogen fluoride, hydrogen chloride and hydrogen cyanide are formed. A special Combustion Product Monitor instrument based on laser spectroscopy was used to analyze their contents.

The results of the Saffire program experiments will help develop models of fire behavior on board spacecraft and take appropriate precautions. This will make space missions safer and help crews return home safely.

Thanks to the Saffire program, researchers have gained a deeper understanding of the likelihood and consequences of fires on spacecraft and will be able to prevent fires on future space missions.