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Focus Fire in Space Evacuation of the ISS In an extreme emergency cases, e.g. in the event of a fire on-board with mortal danger for the crew of the ISS and when a quick extinguishing is not possible, the station must be evacuated. Structural escape routes that would lead outside would naturally be unthinkable outside our atmosphere. Only self rescue via two Sojus capsules of the Russian space agency Roskosmos docked onto the station remain. These capsules currently represent the only way for the astronauts to return to earth and they has been dimensioned for three persons each. Therefore, the maximum crew size of the ISS is currently limited to six persons. The final stage of a Sojus capsule landing is also a fiery issue: shortly before ground contact, the heat shield is blown away from the brake rockets (here on the 11th June 2015 in the steppe of Kazakhstan). fuelled extremely by the strong suction of air and cause even more damage before it is extinguished. Moreover, the vacuum does not help against hot surfaces as there is no convection. Research is also currently being carried out on other possibilities to extinguish flames in zero gravity, e.g. using sound 12 – however, there is no cooling effect with this method so that there is a risk of re-ignition on hot surfaces. Smoke alarm: Life saver In order to detect a fire quickly, the American section of the ISS is equipped with photoelectric smoke detectors and in the Russian part, with ionisation smoke detectors Literatur e and sour ces in the ventilation system. The reason for this is that there is no top or bottom and due to the missing natural convection, the smoke would spread towards the ventilation. Despite this, the astronauts noses and eyes are the most important detection method. Robert Friedman made a report that during the space shuttle missions, the greater part of the incidents that could have resulted in a fire were detected by the noses and eyes of the crew 8. In case of fire: Emergency plan In event of a fire on the ISS, a three stage emergency plan initiates an immediate deactivation of the ventilation and the power supply of the module affected and finally, the 1 https://en.wikipedia.org/wiki/Mir#Accidents 2 Gary A. Ruff: Microgravity Research in Spacecraft Fire Safety, 2001, www.nist.gov/el/fire_research/upload/R0200471.pdf 3 Michelle M. Collins: Fire Protection in manned Missions: Current and planned, www.nist.gov/el/fire_research/upload/R0200469.pdf 4 Howard D. Ross: „Feuer im freien Fall“ in: Spektrum der Wissenschaft 7/1998, S. 35 5 www.nasa.gov/mission_pages/station/research/experiments/480. html und www.news.discovery.com/space/history-of-space/firefighting in-space-nasa-120210.htm 6 Branelle Rodriguez / Gina Young: Development of the International Space Station Fine Water Mist Portable Fire Extinguisher (http://ntrs. nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130011664.pdf), 2013 Source: NASA/Bill Ingalls extinguishing of the fire using carbon dioxide or water mist fire extinguishers. The fire should be extinguished after one minute at the latest. The first fire fighting measure on the ISS is to avoid the flow of air by switching off all ventilation systems. Tests with a burning candle have shown that these go out by themselves if there is no air flow 8. Prevention is the best protection The safest is however, not to allow a fire to start in the first place which is why all materials should be fire-resistant or flameretardant and before being transported to space, must have been subject to a test. But there are exceptions to this rule if special safety measures are observed. The NASA also places their concentration in avoiding ignitable sources. At the beginning of the space race, fire protection was not on the agenda. The NASA only addressed this topic after three astronaut burned to death in their Apollo capsule on the 27th January 1967 during a test, and developed a test method (Limiting Oxygen Index Test – LOI) for determining the flammability . Substantiate extrapolated methods by research Fire prevention, fire detection and fire suppression technologies as well as standards are normally adopted and extrapolated from procedures of the aviation industry. They are fortunately not based on incidents in space. This is why the topic fire in space has a high priority. For 2016, scientists have announced that they will be carrying out different experibe 7 http://www.minesnewsroom.com/news/mines-fire-extinguishersdestined space-station-dec-3 8 Robert Friedman: Fire Safety in the Low-Gravity Spacecraft Environment, 1999, www.asi.org/adb/04/03/14/spacecraft-fire-safety.pdf 9 F. Takahashi, G.T. Linteris, V. R. Katta: Physical and Chemical Aspects of Fire Suppression in Extraterrestrial Environments, 2001, www.fire.nist.gov/bfrlpubs/fire01/PDF/f01020.pdf 10 Angel Abbud-Madrid, James D. Watson, Jess G. Whittington, and J. Thomas McKinnon, Jean-Pierre Delplanque: Study of an ultra-fine Water Mist Suppression System for Spacecraft Fires, 2006 11 http://motherboard.vice.com/read/how-to-put-out-a-fire-in-space 12 http://physicsworld.com/cws/article/news/2015/apr/02/dousingflames with-low-frequency-sound-waves 13 http://www.nasa.gov/feature/nasa-ignites-fire-experiment-aboardspace cargo-ship 16 FeuerTRUTZ International 2.2016


FeuerTRUTZ-International-2-2016
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