At present, the launch of satellite, space shuttle and airship is based on the power which is produced by rocket.It is expensive and not safe.Moreover, it cannot produce thrust powerful enough.

• 目前人造卫星、宇宙飞船，航天飞机等均靠火箭为推力，送人造天体经过地球大气层而进入太空中去，这样费用贵，不安全，又难能产生大推力，送大天体上太空。