1. Three Soviet cosmonauts died in 1971 when a faulty valve caused their Soyuz 11 capsule to depressurise at an altitude of 168 kilometres, shortly before re-entry into the Earth's atmosphere. 1971年，苏联联盟11号飞船在重返地球大气层前的一刻，一个故障阀门在168公里的高空令飞船突然减压，造成机上3名宇航员全部遇难。
