International space stations 国际空间站.ppt

international,space station,introduction,the international space station (iss) is a habitable artificial satellite in low earth orbit. it follows the salyut, almaz, skylab and mir stations as the ninth space station to be inhabited. the iss is a modular structure whose first component was launched in 1998.,like many artificial satellites, the station can be seen with the naked eye from earth without any special equipment. the iss consists of pressurised modules, external trusses, solar arrays and other components. iss components have been launched by american space shuttles as well as russian proton and soyuz rockets.,iss insignia,station structure,the iss is a third generation modular space station. other examples of modular station projects include the soviet/russian mir, russian opsek, and chinese space station.,modular stations can allow the mission to be changed over time and new modules can be added or removed from the existing structure, allowing greater flexibility.,missions,the iss serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology and other fields. the station is suited for the testing of spacecraft systems and equipment required for missions to the moon and mars. in the 2010 united states national space policy, the iss was given additional roles of serving commercial, diplomatic and educational tasks.,scientific research,the iss provides a platform to conduct scientific research that cannot be performed in any other way. while small unmanned spacecraft can provide platforms for zero gravity and exposure to space, space stations offer a long term environment where studies can be performed potentially for decades, combined with ready access by human researchers over periods that exceed the capabilities of manned spacecraft.,life support system,the critical systems are the atmosphere control system, the water supply system, the food supply facilities, the sanitation and hygiene equipment, and fire detection and suppression equipment. the russian orbital segments life support systems are contained in the service module zvezda. some of these systems are supplemented by equipment in the usos (united states orbital segment). the mlm (multipurpose laboratory module) nauka laboratory has a complete set of life support systems.,food,most of the food on board is vacuum sealed in plastic bags. the preserved food is generally not held in high regard by the crew, and when combined with the reduced sense of taste in a microgravity environment, a great deal of effort is made to make the food more palatable.,drinks and soups are sipped from plastic bags with straws, while solid food is eaten with a knife and fork, which are attached to a tray with magnets to prevent them from floating away. any food that does float away, including crumbs, must be collected to prevent it from clogging up the stations air filters and other equipment.,end of mission,russia and its partners have decided to plunge the international space station (iss) into the ocean at the end of its life cycle after 2020, its space agency said on wednesday. after it completes its existence, rkk energia is considering methods to remove from the station some modules of the russian orbital segment and use them as a basis for a new station, known as the orbital piloted assembly and experiment complex (opsek).,by going into a sea grave, the iss will repeat the fate of its predecessor space station mir, which russia sank in the pacific ocean in 2001 after 1