So far this reality has limited spaceflight to multistage expendable rockets or the space shuttle, which is assisted by strap-on fuel tanks and solid-fuel boosters that are jettisoned during ascent.
So far this reality has limited spaceflight to multistage expendable rockets or the space shuttle, which is assisted by strap-on fuel tanks and solid-fuel boosters that are jettisoned during ascent.
目前为止，这个事实使太空飞行限于多阶段扩张式火箭或是太空梭；后者在上升过程中抛出附加的燃料箱和固体燃料助力器。