Vika oxygen generator
Vika or TGK is an oxygen generating system for spaceflight.[1] It is a SFOG, or solid-fuel oxygen generator, a kind of chemical oxygen generator.[1] It is has been used on the retired Mir space station and the International Space Station.[1] It was originally developed by Roscosmos to supplement the Elektron oxygen system on Mir.[1] A Vika module, also known as a "candle", contains about one liter of lithium perchlorate and can provide oxygen for one person for 24 hours.[1]
It was used on Mir when more than three people were on board.[2] Vika needs a supply of canisters to work, which must be flown into space.[2] An example of this is Progress M-34, which carried 60 canisters to Mir in 1997 along with other cargo.[2] If Vika and Elektron stopped working the station would have to rely on a limited supply of bottled oxygen.[2]
After being adopted for use on the ISS, it had the NASA name SFOG, but they also sometimes use the Russian acronym TGK.[1]
Vika on Mir
On 23 February 1997, during the exchange of an air filter, a failed chemical oxygen generator spewed a torch-like jet of a molten metal and sparks across one of the Mir space station modules, burning for 14 minutes and blocking the escape route to one of the Soyuz spacecraft. The accident was caused by a leak of the lithium perchlorate from one of the canisters.[citation needed]
Vika on ISS
A backup to the temperamental Elektron system used on both the ISS and Mir is the Vika solid-fuel oxygen generator (SFOG), which contains a replaceable cartridge, a thin walled steel tube with a three-part block of oxygen-releasing mixture based on lithium perchlorate. Two parts are tablets of the chemical mixture and the third one is the igniter tablet with a flash igniter. The igniter is struck by a firing pin when the device is activated. One cartridge releases 600 litres (160 US gal) of oxygen and burns for 5–20 minutes at 450–500 °C (842–932 °F)[3] The oxygen is cooled and filtered from dust and odours, and released into the space station atmosphere.[citation needed]