NASA needs good weather to launch Ares I-X because engineers need to see the rocket flight all the way through first stage separation, which will mark the end of the test.

NASA需要好天气来发射战神I-X，因为工程师们要在第一级火箭分离前观测火箭飞行全过程，第一级火箭分离标志着试飞的结束。

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The 1-x will climb about 40km (25 miles) into the sky during the powered phase of its flight, continuously measuring vehicle aerodynamics, controls and performance of the rocket's first stage.

战神一号X型将上升到约40公里(约25英里)的高空，在其动力飞行阶段，将不间断地对其运载空气动力学指标、火箭的第一阶段的控制和表现进行测量。

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Military aviation experts said the fighter? Known as the J-20? Appeared to be conducting high-speed taxi tests, which are usually the final stage before a test flight.

空军专家说这架战机，也就是J20似乎在做高速滑行实验，这通常是试飞前的最后一个步骤。

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This would involve a two-stage interceptor that is scheduled to be flight tested three times between now and the end of 2011.

VOA: standard.2009.07.15

It's specifically designed to shoot down missiles during their final stage of flight, and is expected to arrive on Guam within the next few weeks.

NPR: North Korea Threats Spark Buzz On Guam, Not Panic

And, similar to Dyson, Lugg is proposing to achieve these radical efficiencies by coordinating multiple engine systems (analogous to the acceleration, inducement and entrainment of the Air Multiplier) to create optimal conditions for each stage of flight and to use the excess energy the system produces to create a plasma field to reduce drag and eliminate sonic boom.

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It will use a balloon to carry its rocket on the first stage of its flight.

BBC: NEWS | Science/Nature | Space future: Race for the X-Prize