欧洲航天局(ESA)授权开展的一项研究得出结论:基于云霄塔(Skylon)可重复使用空天飞机的欧洲航天发射活动具备经济可行性。云霄塔空天飞机与目前欧洲正在使用的运载火箭完全不同,它能像飞机一样从常规跑道上水平起降,其核心技术在于新型推进系统,它能在低空低速下像喷气式发动机一样工作,但到高空高速(马赫数5)后又能转换为纯 A study commissioned by the European Space Agency (ESA) concluded that European space launch activities based on the Skylon reusable space shuttle were economically viable. The Skylight space shuttle is completely different from the launch vehicle currently being used in Europe. It can fly and take off horizontally from a conventional runway like a plane. Its core technology lies in the new propulsion system, which works like a jet engine at low altitude and low speed. But to high-altitude high-speed (Mach 5) can be converted to pure