美国航空航空天局(NASA)的研究人员正在制定先进的宇宙飞船设计方案,试图使将来的太空旅行能像现在的空中旅行一样普遍,而实现这一梦想的关键是解决动力问题。目前宇宙飞船使用的化学火箭都要燃烧大量燃料,其能量可用于驱动200万辆家用轿车。同时,宇宙飞船还得携带大量装备和数名宇航员,另外,还得带上足够宇航员用两个星期的食品、空气和水。如果要到火星的话,还得带足够的燃料用于往返,这样,发射所需的费用相当惊人,飞行速度也受 Researchers at NASA are developing state-of-the-art spacecraft designs that attempt to make future space travel as commonplace as current air travel, and the key to making that dream come true is to solve the power problem. At present, chemical rockets used by spacecraft burn a lot of fuel, and their energy can be used to drive 2 million passenger cars. At the same time, the spacecraft would have to carry a large amount of gear and several astronauts, plus enough space for astronauts for two weeks, air and water. If you want to Mars, you also have to bring enough fuel for the round trip, so that the cost of launching astonishing, flying speed is also affected