VOA慢速英语:安全问题推迟了美国重新开始载人航天飞行的努力

capsule - n. a small part of the spacecraft where people live and work

item - n. a separate part or thing

shield - n. something that defends or protects something

canister - n. a metal case that contain gas, chemical or fuel

challenge - n. a difficult task or problem

schedule - n. a plan of the times when something will be done

precedence - n. a condition of being more important than something else

exceed - v. to be greater or more than something

faulty - adj. having a mistake

valve - n. a mechanical device that controls the flow of liquid, gas, etc. by opening and closing