|
The International Space Station Environmental Control and Life Support System (ECLSS) is a life support system that provides or controls atmospheric pressure, fire detection and suppression, oxygen levels, waste management and water supply. The highest priority for the ECLSS is the ISS atmosphere, but the system also collects, processes, and stores waste and water produced and used by the crew—a process that recycles fluid from the sink, shower, toilet, and condensation from the air. The Elektron system aboard ''Zvezda'' and a similar system in ''Destiny'' generate oxygen aboard the station. The crew has a backup option in the form of bottled oxygen and Solid Fuel Oxygen Generation (SFOG) canisters. Carbon dioxide is removed from the air by the ''Vozdukh'' system in ''Zvezda''. Other by-products of human metabolism, such as methane from the intestines and ammonia from sweat, are removed by activated charcoal filters.〔 == Water recovery systems == The ISS has two water recovery systems. ''Zvezda'' contains a water recovery system that processes waste water from showers, sinks, and other crew systems and water vapor from the atmosphere that could be used for drinking in an emergency but is normally fed to the Elektron system to produce oxygen. The American segment has a Water Recovery System installed during STS-126 that can process water vapour collected from the atmosphere, waste water from showers, sinks, and other crew systems, and also urine into water that is intended for drinking. The Water Recovery System was installed initially in ''Destiny'' on a temporary basis in November 2008〔 and moved into ''Tranquility'' (Node 3) in February 2010. The Water Recovery System consists of a Urine Processor Assembly and a Water Processor Assembly, housed in two of the three ECLSS racks. The Urine Processor Assembly uses a low pressure vacuum distillation process that uses a centrifuge to compensate for the lack of gravity and thus aid in separating liquids and gasses. The Urine Processor Assembly is designed to handle a load of 9 kg/day, corresponding to the needs of a 6-person crew.〔 Although the design called for recovery of 85% of the water content, subsequent experience with calcium sulfate precipitation〔 (in the free-fall conditions present on the ISS, calcium levels in urine are elevated due to bone density loss) has led to a revised operational level of recovering 70% of the water content. Water from the Urine Processor Assembly and from waste water sources are combined to feed the Water Processor Assembly that filters out gasses and solid materials before passing through filter beds and then a high-temperature catalytic reactor assembly. The water is then tested by onboard sensors and unacceptable water is cycled back through the water processor assembly.〔〔 The Volatile Removal Assembly flew on STS-89 in January 1998 to demonstrate the Water Processor Assembly's catalytic reactor in microgravity. A Vapour Compression Distillation Flight Experiment flew, but was destroyed, in STS-107.〔 The distillation assembly of the Urine Processor Assembly failed on November 21, 2008, one day after the initial installation.〔 One of the three centrifuge speed sensors was reporting anomalous speeds, and high centrifuge motor current was observed. This was corrected by re-mounting the distillation assembly without several rubber vibration isolators. The distillation assembly failed again on December 28, 2008 due to high motor current and was replaced on March 20, 2009. Ultimately, during post-failure testing, one centrifuge speed sensor was found to be out of alignment and a compressor bearing had failed.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ISS ECLSS」の詳細全文を読む スポンサード リンク
|