People could land on Mars in the next 20 to 30 years provided scientists can find water on the red planet, the head of NASA's surface exploration mission said on September 16. Such a mission would take 11 to 12 months to get to Mars and it would be impossible to carry enough water for the astronauts. Meanwhile, water is needed to make rocket fuel for the return journey, to cool the spacecraft and to generate energy. “If we cannot find water，it really makes it difficult to send humans. Water is the key,” said Thompson, a famous engineer.

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9月16日，美国国家宇航局火星地表探测任务小组的负责人表示，如果科学家们能够在火星上找到水源的话，人类就可能在未来20到30年后登上火星。将人类送上火星需要11至12个月的时间，宇航员不可能携带足够量的水，而且，火箭返航时也需要水来制作燃料、冷却航天器、生产能源。著名工程师汤普森说：“如果我们找不到水的话，把人类送上火星是非常困难的。水是关键因素。”