【正文】
ng for chemicals, fires and other disasters. The International Space Station is now in orbit and permanently crewed. With many different partners contributing to its design and construction, this highflying laboratory has bee a symbol of cooperation in space exploration, with former petitors now working together. And while the space shuttle will likely continue to carry out important space missions, particularly supporting the International Space Station, the Columbia disaster in 2020 signaled the need to step up the development of its replacement. Future space launch systems will be designed to reduce costs and improve dependability, safety, and reliability. In the meantime most . military and scientific satellites will be launched into orbit by a family of expendable launch vehicles designed for a variety of missions. Other nations have their own launch systems, and there is strong petition in the mercial launch market to develop the next generation of launch systems.