An ISS Oxygen Candle Turns Out to be a Dud

NASA Space Station On-Orbit Status 26 May 2005

“Update on Solid-Fuel Oxygen Generator (SFOG) “candles”: As of tonight, since 5/20 a total of 9 candles have been decomposed on board (total attempts: 10 [i.e., 1 dud]).”

NASA Space Station On-Orbit Status 24 May 2005

“The crew burned one SFOG (solid-fuel oxygen generator) “candle” today to increase ppO2 (oxygen partial pressure). An attempt to burn a second candle, however, was unsuccessful. [Russian ECLS specialists have estimated that approximately 20% of the onboard SFOGs will not ignite, which is taken into account in the onboard O2 supplies estimates.”