But while higher is better from a fuel conservation perspective, there is an upper limit on how high it is safe to orbit humans for long periods.

越高耗费的燃料越少，而载人飞船能够长时间安全飞行的轨道高度就有上限。

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China will conduct research into the technologies for low-cost launch vehicles, new upper stage and the reusable space transportation system between the earth and low-earth orbit.

开展低成本运载火箭、新型上面级、天地往返可重复使用运输系统等技术研究。

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The satellite was released from the launcher upper stage and entered the projected orbit.

卫星同发射装置分离进入指定轨道。

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"After a good flight of the solid boosters and core cryogenic stage, there was a problem with the upper stage and the desired orbit was not attained, " Arianespace Chairman and CEO Jean-Marie Luton announced after the mission.

CNN: Ariane rocket puts satellites in defective orbit

The rocket was intended to lift the satellite into an orbit 35, 696 kilometers above the earth, but during its final burn, the upper stage engine shut down four minutes early, and the satellite was released into too low of an orbit.

FORBES: Another Russian Rocket Misses The Target

"Arianespace Flight 142 placed its dual satellite payload in a lower than desired orbit following a problem with the launcher's upper stage, " the statement said.

CNN: Ariane rocket puts satellites in defective orbit