NASA launched an empty spacecraft away from the ISS and set materials inside on fire; scientists used the experiment to study how flames spread in space

NASA once sent an uncrewed Cygnus cargo spacecraft away from the International Space Station and then ignited combustible materials inside it. The unusual experiment was designed to help researchers study how fire behaves and spreads in microgravity.

The experiment was part of NASA’s Spacecraft Fire Safety Demonstration Project, known as Saffire. The program used uncrewed Cygnus spacecraft after their missions to the ISS, allowing researchers to conduct combustion experiments without putting astronauts aboard the station in the test environment.

NASA Ignited Materials After Cygnus Left the ISS

The first investigation, Saffire-I, took place in June 2016 aboard an uncrewed Cygnus spacecraft.


After Cygnus was released from the International Space Station and moved away from it, the fire experiment was activated.

NASA did not set the entire spacecraft on fire. Instead, equipment inside Cygnus ignited specific combustible test materials so researchers could observe the resulting flames.

During Saffire-I, researchers burned a cotton-fiberglass material blend. NASA reported that the flame burned across the sample for about eight minutes.

Why NASA Studied Fire in Space

Saffire was designed to investigate combustion and fire behavior in spacecraft environments.

Conducting the experiments on an uncrewed Cygnus after it had departed the ISS allowed NASA to study fire without conducting the experiment inside the occupied space station.

The investigations examined how fires grow and spread in microgravity and how combustible materials behave during combustion in a spacecraft environment.

Scientists Studied How Flames Spread

The Saffire experiments collected data on flame growth and spread in microgravity.

NASA reported that experiments involving thin fabrics showed that flames can reach a steady spread rate and a limiting length in microgravity. Researchers also found that reducing pressure slows flame spread.

Across the Saffire investigations, NASA used different combustible materials and experimental conditions to collect information about combustion and flame behavior in space.

NASA Conducted Six Saffire Investigations

Saffire was a series of investigations rather than a single experiment.

The program included six investigations, designated Saffire-I through Saffire-VI, examining fire behavior in spacecraft environments.

Later experiments included Saffire-V, which investigated larger fires inside an uncrewed Cygnus after its primary mission to the International Space Station.

Saffire-VI was the final investigation in the Saffire series.

What Did NASA Set on Fire in Cygnus Spacecraft

NASA ignited selected combustible materials inside an uncrewed Cygnus spacecraft after it had departed the ISS. The spacecraft itself was not the material being tested.

The purpose of the Saffire experiments was to collect data on combustion, flame growth and flame spread under microgravity conditions.