International Space Station Celebrates 15 Years in Orbit

Thursday, Nov. 20, marks 15 years since the first piece of the International Space Station was launched into orbit. The space station's completion saw great triumphs as well as tragedy, the end of one era in human space exploration and the beginning of another. The ISS stands as a critical platform for advancing humanity's presence beyond Earth's orbit, and is, according to senior NASA scientist Harley Thronson, "the essential demonstration site and steppingstone for a sustained future in space with humans."